ARAC Recommendations, 14 CFR 25.1322

requirements that are not fully met by the current guidance. (For example, manufacturers and installers of liquid crystal display based systems are considered ``users'' whose needs may not currently be met.) d. Review other advisory circulars (such as AC's/ACJ's for various systems) and other industry documents to understand their relevance to AC 25-11. Additionally, recent industry activities have produced materials (for example, Aviation Recommended Practices) that may be useful in developing the harmonized AC. e. Recommend a format of the advisory circulars that can accommodate future changes. The current AC/ACJ format is not conducive to additions as new systems are developed, new functions are identified, and new technologies are employed. The revised harmonized AC/ACJ should be formatted to accommodate future changes. For each task, ARAC is to review airworthiness, safety, cost, and other relevant factors, including recent certification and fleet experience. ARAC will submit a report to the FAA (format and content to be determined by the FAA) that recommends revisions to the regulation, including cost estimates, and outlines the information and background for the advisory circulars. If a notice of proposed rulemaking or notices of proposed advisory circulars are published for public comment as a result of the recommendations, ARAC may be further asked to review all comments received and provide the FAA with a recommendation for disposition of public comments for each project. [[Page 19797]] Schedule: The report and draft advisory circular is to be completed no later than 24 months after the FAA publishes the tasks in the Federal Register. ARAC Acceptance of Tasks ARAC accepted and assigned the task to the Avionics Systems Harmonization Working Group. The working group serves as staff to ARAC and assists in the analysis of the assigned task. ARAC must review and approve each working group's recommendations. If ARAC accepts the working group's recommendations, it will forward them to the FAA. Recommendations that are received from ARAC will be submitted to the agency's Rulemaking Management Council to address the availability of resources and prioritization. Working Group Activity The Avionics System Harmonization Working Group must comply with the procedures adopted by ARAC. As part of the procedures, the working group must: 1. Recommend a work plan for completing each task, including the rationale supporting such a plan for consideration at the October 15- 16, 2002, meeting of the ARAC on transport airplane and engine issues. 2. Give a detailed conceptual presentation of the proposed recommendations before proceeding with the work stated in item 3. 3. Draft the appropriate documents and required analyses and/or any other related materials or documents. 4. Provide a status report at each ARAC meeting on transport airplane and engine issues. Participation in the Working Group The Avionics Systems Harmonization Working Group is composed of technical experts having an interest in the assigned tasks. A working group member need not be a representative or a member of the full committee. An individual who has expertise in the subject matter and wishes to become a member of the working group should write to the person listed under the caption FOR FURTHER INFORMATION CONTACT expressing that desire, describing his or her interest in the task, and stating the expertise he or she would bring to the working group. All requests to participate must be received no later than (1 month after publication of the tasking statement). The requests will be reviewed by the assistant chair, the assistant executive director, and the working group co-chairs. Individuals will be advised whether their request can be accommodated. Individuals chosen for membership on the working group must represent their aviation community segment and actively participate in the working group (e.g., attend all meetings, provide written comments when requested to do so, etc.). They must devote the resources necessary to support the working group in meeting any assigned deadlines. Members are expected to keep their management chain and those they may represent advised of working group activities and decisions to ensure the proposed technical solutions do not conflict with their sponsoring organization's position when the subject being negotiated is presented to ARAC for approval. Once the working group has begun deliberations, members will not be added or substituted without the approval of the assistant chair, the assistant executive director, and the working group co-chairs. The Secretary of Transportation determined that the formation and use of the ARAC is necessary and in the public interest in connection with the performance of duties imposed on the FAA by law. Meetings of the ARAC will be open to the public. Meetings of the Avionics Systems Harmonization Working Group will not be open to the public, except to the extent that individuals with an interest and expertise are selected to participate. The FAA will make no public announcement of working group meetings. Issued in Washington, DC, on April 11, 2002. Anthony F. Fazio, Executive Director, Aviation Rulemaking Advisory Committee. [FR Doc. 02-9947 Filed 4-22-02; 8:45 am] BILLING CODE 4910-13-M Recommendation Letter Pratt & Whitney 400 Main Street East Hartford, Connecticut 06108 May 14, 2004 Federal Aviation Administration 800 Independence Avenue SW Washington, D.C. 20591 Attention: Mr. Nicholas Sabatini, Associate Administrator for Regulation and Certification Subject: ARAC Recommendations, 14 CFR 25.1322 Reference: ARAC Tasking, Federal Register, dated April 23, 2002 Dear Nick, The Transport Airplane and Engine Issues Group is pleased to submit the following as a recommendation to the FAA in accordance with the reference tasking. The Avionics Systems Harmonization Working Group has prepared this information. ASHWG Report – 14 CFR 25.1322 The TAEIG unanimously accepted the ASHWG report. During the discussion, the industry representatives on TAEIG felt that when considering the acceptability of these colors for graphical weather depiction, the potential safety benefits should be considered during the certification process. Sincerely yours, Craig R. Bolt Assistant Chair, TAEIG boltcr@pweh.com (Ph: 860-565-9348/Fax: 860-557-2277) Copy: Dionne Krebs – FAA-NWR Mike Kaszycki – FAA-NWR Alicia Douglas – FAA-Washington, D.C. Clark Badie - Honeywell Acknowledgement Letter SEP 2 0 2004 Mr. Craig R. Bolt Assistant Chair, Aviation Rulemaking Advisory Committee Pratt & Whitney 400 Main Street, Mail Stop 162-14 East Hartford, CT 06108 Dear Mr. Bolt: This letter acknowledges receipt of several letters that you sent for the Avi~tion Rulemaking Advisory Committee (ARAC) on Transport Airplane and Enginf (TAE) Issues. 1, Date of Description of Recommendation Working Group Letter 01/06/2003 Proposed rule and draft advisory material on bird Engine Harmonization ingestion capability (§ 33. 76) Workin~ I Group (HWG) 10/22/2003 Final report and position statements on bird strike Genera Structures requirements (§ 25.631) HWG 10/22/2003 Final report and draft advisory material on alterna- Genera Structures tive composite structure material (§ 25.603) HWG I 05/14/2004 Final report, proposed rule language, and draft Avionic~ Systems HWG advisory material on warning, caution, and advi- I I sory alerts installed in the cockpit (§ 25.1322) I ! 06/17/2004 Final repo~ and draft advisory material on fire pro- Loads •rd Dynamics tection of flight controls, engine mounts and other HWG flight structures (§ 25.865) 06/22/2004 Final report, proposed rule, and draft advisory ma- Human i:actor HWG terial on installed systems and equipment for use by the flight crew (§ 25.1302) I wish to thank the ARAC and the working groups for the resources that ind i.Jstry gave to develop these recommendations. The recommendations from the, ~vionics Systems HWG, the Human Factor HWG, and the Loads and Dynamics H\/v Gwill remain open until these working groups complete a Phase 4 review. The rE maining recommendations have been closed, as we consider submittal of the report $ as completion of the tasks. All of these recommendations will be placed on thi ,ARAC . . . website at http.//www.faa.gov/avr/arm/arac/mdex.cfm. tJ. ( We will continue to keep you apprised of our efforts on the ARAC recomm¢mdations and the rulemaking prioritization at the regular ARAC TAE issues meetings. I Sincerely, Original Signed By Margaret Gilligan Nicholas A. Sabatini Associate Administrator for Regulation and Certification cc: ARM-1/20/200/204/207; AIR-100, ANM-110 ARM-207:Jlinsenmeyer:fs:8/12/04:PCDOCS # 21644 Control Nos. 20041855-0; 20041944-0; 20042001-0 2 Recommendation ARAC WG Report FAR/JAR 25.1322 & AC/ACJ 25.1322 1. What is underlying safety issue addressed by the FAR/JAR? The rule provides color requirements for warning, caution and advisory lights associated with alerting functions. However, the current rule only addresses “lights” and does not take into consideration the implementations, technology, and associated safety issues with the latest flight deck alerting systems. FAR/JAR 25.1322 describes standards for the color of warning, caution, advisory, and other message lights that are installed as annunciation displays in the flight deck. It addresses visual alerting cues only in the form of colored lights installed in the flight deck. The regulation became effective February 1, 1977 (Amendment No. 25-38, 41 FR 44567, December 20, 1976) and has never been amended. It does not consider the use of corresponding aural tones/voice and prioritization of multiple alerts that may occur at the same time. Nor does it consider new technologies, other than colored lights, that may be more effective in aiding the flight crew in decision making. Further, FAR/JAR 25.1322 is outdated, does not address safety concerns associated with today’s display systems, and has resulted in additional work for applicants when showing compliance, and for the FAA when addressing new flight deck designs and the latest display technologies via special conditions and issue papers. 2. What are the current FAR and JAR standards? Current FAR text: If warning, caution, or advisory lights are installed in the cockpit, they must, unless otherwise approved by the Administrator, be-- (a) Red, for warning lights (lights indicating a hazard which may require immediate corrective action); (b) Amber, for caution lights (lights indicating the possible need for future corrective action); (c) Green for safe operation lights; and (d) Any other color, including white, for lights not described in paragraphs (a) through (c) of this section, provided the color differs sufficiently from the colors prescribed in paragraphs (a) through (c) of this section to avoid possible confusion. Current JAR text: If warning, caution, or advisory lights are installed in the cockpit, they must, unless otherwise approved by the Authority, be - (a) Red, for warning lights (lights indicating a hazard which may require immediate corrective action); (b) Amber, for caution lights (lights indicating the possible need for future corrective action); (c) Green, for safe operation lights; and (d) Any other colour, including white, for lights not described in sub-paragraphs (a) to (c) of this paragraph, provided the colour differs sufficiently from the colours prescribed in sub-paragraphs (a) to (c) of this paragraph to avoid possible confusion. 3. What are the differences in the standards and what do these differences result in?: There are no differences in the standards. There is a related AMJ, but no AC. 4. What, if any, are the differences in the means of compliance? Specific means of compliance to JAR 25.1322 are provided in the associated AMJ. No specific means of compliance exists for FAR 25.1322. 5. What is the proposed action? The FAR 25 and JAR 25 and their associated guidance material have been identified as lacking content and guidance commensurate with the state-of-the-art. Therefore, a new FAR/JAR 25.1322 will be written to address current or future flight deck design and the technologies associated with flight crew alerting. The existing AMJ will be reviewed and harmonized advisory material will be generated. 6. What should the harmonized standard be? A new FAR/JAR 25.1322 and associated AC/AMJ 25.1322. (See Attachment and file Draft AC25.1322 DC Meeting 1003_rev a) 7. How does this proposed standard address the underlying safety issue (identified under #1)? The new standard will address the requirements for crew alerting systems and provide content and guidance that is commensurate with the state-of-the-art flight deck alerting systems. 8. Relative to the current FAR, does the proposed standard increase, decrease, or maintain the same level of safety? The level of safety will be increased by providing new standards and guidance material that is commensurate with the state-of-the-art and crew alerting, and by providing guidance for other Part 25 regulations that require the use of alerting. 9. Relative to current industry practice, does the proposed standard increase, decrease, or maintain the same level of safety? The new standards and guidance material supports current industry practice and will increase the level of safety. 10. What other options have been considered and why were they not selected?: The group initially thought of adopting the JAR and associated AMJ. However, this was still deemed insufficient for today’s flight deck alerting systems. The level of effort to rewrite the rule was significant, and each sub-paragraph was reviewed and many options were considered. In addition, the Human Factors Harmonization Working Group provided additional options for consideration. The group has modified wording in the draft AC/ACJ to address the means of compliance to sub paragraph e) in the rule. 11. Who would be affected by the proposed change? The (Part 25) aviation industry in general including aircraft manufacturers, aircraft operators, avionics manufacturers, and regulators, if they are not already practicing the essence of these standards. There may be indirect effect to manufacturers that wish to develop products and systems that are intended to cross part 23/25/27/29 applications. 12. To ensure harmonization, what current advisory material (e.g., ACJ, AMJ, AC, policy letters) needs to be included in the rule text or preamble? AC/AMJ 25-11, and parts of the draft AC/AMJ 25-1322. 13. Is existing FAA advisory material adequate? No. There is no existing FAA advisory material. However, there is an existing AMJ 25.1322 and that document has been revised to incorporate this latest information. 14. How does the proposed standard compare to the current ICAO standard? There are no applicable ICAO standards. 15. Does the proposed standard affect other HWGs? Yes. We have coordinated with the working groups responsible for Human Factors (25.1301(e)), Propulsion and Safety (25.1309). We have also coordinated with other industry groups such as the RTCA SC-195 committee. 16. What is the cost impact of complying with the proposed standard? For those manufacturers that are already in compliance / already practicing. Harmonization of 25.1322 and the associated guidance material will significantly reduce certification costs, thereby improving the allocation of limited resources. For those manufacturers that are not in compliance/not already practicing, there may be additional costs to comply with the new rule. There is a general potential problem with the change process, if this revised rule is used for new applications of existing products and systems, or if this revised rule is applied to any modifications to existing products and systems. 17. Does the HWG want to review the draft NPRM at “Phase 4” prior to publication in the Federal Register? Yes 18. In light of the information provided in this report, does the HWG consider that the “Fast Track” process is appropriate for this rulemaking project, or is the project too complex or controversial for the Fast Track Process? Yes, it is appropriate for the “Fast Track” process. The group identified an issue regarding sub paragraph (e) in the draft rule that caused controversy. The group resolved this to our satisfaction by revising both the regulation and advisory material, based on comments received from the RTCA SC-195 committee and from within group membership. The AVHWG will also update AC/AMJ 25-11 to cover the broad scope of the use of colors in the flight deck. FAR/JAR 25.1322 Flight Crew Alerting (a) When flight crew alerts are provided they must: 1) Provide timely attention-getting cues through at least two different senses by combination of aural, visual, or tactile indications, for crew alerts requiring immediate flight crew awareness. 2) Provide the flight crew with the information needed to identify the alert and determine correct action, if any. 3) Be readily and easily detectable and intelligible by the flight crew under all foreseeable operating conditions including conditions where multiple alerts are provided. (b) Alerts must conform to the following prioritization hierarchy based upon urgency of flight crew awareness and urgency of flight crew response. 1) Warning: For conditions that require immediate flight crew awareness and immediate flight crew response. If warnings are time critical to maintain the immediate safe operation of the airplane, they must be prioritized higher than other warnings. 2) Caution: For conditions that require immediate flight crew awareness and subsequent flight crew response. 3) Advisory: For conditions that require flight crew awareness and may require subsequent flight crew response. (c) Alert presentation means must be designed to minimize nuisance effects. In particular a crew alerting system must: 1) Permit each occurrence of attention getting cues, if provided, to be acknowledged and suppressed unless they are otherwise required to be continuous. 2) Prevent the presentation of an alert that is inappropriate or unnecessary for the particular phase of operation. 3) Remove the presentation of the alert when the condition no longer exists 4) Provide a means to suppress an attention getting component of an alert caused by a failure of the alerting system, and/or the sensors, which interfere with the flight crew’s ability to safely operate the aircraft. This means must not be readily available to the flight crew such that it could be operated inadvertently, or by habitual reflexive action. In this case, there must be a clear and unmistakable annunciation to the flight crew that the alert has been suppressed. (d) Alerts must conform to the following color convention for visual alert indications: 1) Red for Warning alert indications. 2) Amber/yellow for Caution alert indications. 3) Any color except red or green for Advisory alert indications. (e) The colors red and amber/yellow are normally reserved for alerting functions. The use of these colors for functions other than crew alerting must be limited and must not adversely affect crew alerting. Final Version AC/ACJ 25.1322 – Updated April 2004 in London. Flight Crew Alerting Table of Contents 1. PURPOSE ................................................................................................................................ 6 2. SCOPE...................................................................................................................................... 6 3. RELATED REGULATIONS ................................................................................................... 7 4. RELATED DOCUMENTS ...................................................................................................... 8 4.a Federal Aviation Administration Documents. .................................................................. 8 4.b JAA Documents................................................................................................................ 9 4.c Industry Documents.......................................................................................................... 9 5. BACKGROUND...................................................................................................................... 9 6. DEFINITIONS ......................................................................................................................... 9 7. GENERAL ............................................................................................................................. 12 7.a Alerting Presentation Elements ...................................................................................... 13 7.b Functional Components for each type of Alert.............................................................. 13 7.c Alerting System Reliability and Integrity....................................................................... 15 8. Management of AlertS............................................................................................................ 15 8.a Prioritization ................................................................................................................... 15 8.b Alert Inhibits................................................................................................................... 16 8.c Clear/Recall of visual alert messages ............................................................................. 17 8.d Considerations for interface or integration with other systems (ex. Checklist, synoptics, switches, discrete lamps)............................................................................................................................ 17 8.e Color standardization...................................................................................................... 17 8.f Suppression of False Alerts ............................................................................................ 18 9. Certification TEST and evaluation considerations ................................................................. 18 10. RETROFIT applicability .................................................................................................... 19 10.a Purpose ........................................................................................................................... 19 10.b Visual Alerts................................................................................................................... 19 10.c Aural Alerts .................................................................................................................... 20 10.d Special Considerations for Head-Up Displays (HUDs).................................................. 20 Appendix A EXAMPLES FOR THE INCLUSION OF Visual System Elements IN AN ALERTING SYSTEM ........................................................................................................................................ 22 A.1 Master Visual.................................................................................................................. 22 A.2 Visual Information.......................................................................................................... 23 A.3 Time Critical Warning Visual Information .................................................................... 25 A.4 Failure Flags ................................................................................................................... 25 Appendix B EXAMPLES FOR INCLUSION OF Aural System Elements IN AN ALERTING SYSTEM ........................................................................................................................................................ 26 B.1 Master Aural Alert and Unique Tones............................................................................ 26 B.2 Voice Information .......................................................................................................... 28 PURPOSE This advisory circular (AC) provides guidance for the design and approval of flight crew Alerting Functions installed in transport category airplanes. SCOPE This advisory circular applies to the installation, integration, and certification of flight deck alerting systems, whether they are integrated or not. That is, it applies to individual aircraft systems that provide alerts that may or may not be integrated with a central alerting system, as well as systems whose primary function is alerting, such as a central alerting system. The alerting system may be approved as part of a TC/STC/ATC/ASTC. This AC provides guidance as to what is considered an alert. However, what should be alerted to the flight crew is dependent on the specific design and overall flight deck philosophy. For example, the failure of a single sensor in a multi-sensor system in some cases may not necessarily result in an alert condition that the pilot needs to be aware of. However, for a single sensor system such a failure would certainly result in alert. Thus, the applicant should discuss the overall flight deck design and alerting philosophy with the Authority when determining what should be alerted to the flight crew. Any system that provides an alert should follow the guidance in this AC. Like all AC material, this AC is not mandatory and does not constitute a regulation. It is issued to provide guidance and to outline a method of compliance with rules and in particular 25.1322. RELATED REGULATIONS The following list of regulations describe requirements for flight crew alerting for which this advisory circular provides guidance. CFR/JAR 25.207 Stall warning CFR/JAR 25.253(a)(2) High-speed characteristics CFR/JAR 25.672(a) Stability Augmentation… CFR/JAR 25.679(a) Control system gust locks CFR/JAR 25.703 Takeoff warning system CFR/JAR 25.729(e) Retracting mechanism CFR/JAR 25.783(e) Doors CFR/JAR 25.812(f)(2) Emergency lighting CFR/JAR 25.819(c) Lower deck service compartments CFR/JAR 25.841(b)(6) Pressurized cabins CFR/JAR 25.854(a) Lavatory fire protection CFR/JAR 25.857(b)(3) Cargo compartment classification CFR/JAR 25.857(c)(1) Cargo compartment classification CFR/JAR 25.857(e)(2) Cargo compartment classification CFR/JAR 25.859(e)(3) Combustion heater fire protection CFR/JAR 25.863(c) Flammable fluid fire protection CFR/JAR 25.1019(a)(5) Oil strainer or filter CFR/JAR 25.1165(g) Engine ignition systems CFR/JAR 25.1203(b)(2) CFR/JAR 25.1203(b)(3) Fire-detector system CFR/JAR 25.1203(f)(1) Fire-detector system CFR/JAR 25.1303(c)(1) Flight and navigation instruments CFR/JAR 25.1305(a)(1) CFR/JAR 25.1305(a)(5) Powerplant instruments CFR/JAR 25.1305(c)(7) Powerplant instruments CFR/JAR 25.1309(c) Equipment, systems, and installations CFR/JAR 25.1309(d)(4) Equipment, systems, and installations CFR/JAR 25.1322 Warning, caution, and advisory lights CFR/JAR 25.1326 Pitot heat indication systems CFR/JAR 25.1331(a)(3) Instruments using a power supply CFR/JAR 25.1353(c)(6)(ii) Electrical equipment and installations CFR/JAR 25.1419(c) Ice protection CFR/JAR 25.1517(3) Rough air speed, VRA CFR/JAR 25, Appendix I Section 25.6 Installation of an Automatic Takeoff Thrust Control System (ATTCS) Powerplant Instruments CFR/JAR 33.71(b)(6) Lubrication system. CFR/JAR 91.219 Altitude alerting system or device: Turbojet powered civil airplanes CFR/JAR 91.221 Traffic alert and collision avoidance system equipment and use CFR/JAR 91.223 Terrain awareness and warning system CFR/JAR 91.603 Aural speed warning device CFR/JAR 91, Appendix A Section 91.2(b)(1) Required instruments and equipment CFR/JAR, Appendix G Section 91.2(c)(3) Operations in Reduced Vertical Separation Minimum (RVSM) Airspace - Aircraft approval CFR/JAR 91, Appendix G Section 91.3(c)(6) Instruments and Equipment Approval CFR/JAR 121.221(c)(1) Fire precautions CFR/JAR 121.221(d)(1) Fire precautions 14 CFR 121.221(f)(2) Fire precautions 14 CFR 121.289 Landing gear: Aural warning device. 14 CFR 121.307(k) Engine instruments 14 CFR 121.308(a) Lavatory fire protection. 14 CFR 121.319(b) Crewmember interphone system 14 CFR 121.354 Terrain awareness and warning system 14 CFR 121.356(b) Traffic alert and collision avoidance system CFR/JAR 121.358 Low-altitude windshear system equipment requirements CFR/JAR 121.360(a) CFR/JAR 121.360(e) CFR/JAR 121.360(f) Ground proximity warning-glide slope deviation alerting system CFR/JAR 125.187 Landing gear: Aural warning device. CFR/JAR 125.205(d) Equipment requirements: Airplanes under IFR. CFR/JAR 125.221(a) Traffic alert and collision avoidance system CFR/JAR 135.150(b)(7) Public address and crewmember interphone system 14 CFR 135.153(a) Ground proximity warning system. 14 CFR 135.154 Terrain awareness and warning system 14 CFR 135.163(d) Equipment requirements: Aircraft carrying passengers under IFR. 14 CFR 135.180(a) Traffic alert and collision avoidance system 14 CFR 135, Appendix A Section A135.1 Additional Airworthiness Standards for 10 or More Passenger Airplanes RELATED DOCUMENTS Only those sets of materials that were used as reference for this AC/AMJ are listed. 1.a Federal Aviation Administration Documents. (1) Report DOT/FAA/RD-81/38, II, Aircraft Alerting Systems Standardization Study, Volume II, Aircraft Alerting Systems Design Guidelines. This document can be obtained from the National Technical Information Service, Springfield, Virginia 22166 (2) AC 25-11, Transport Category Airplane Electronic Display Systems 7/16/87 (3) Report DOT/FAA/CT-96/1 - GAMA Report No 10, “Recommended Guidelines for Part 23 Cockpit/Flight Deck Design” (September 2000), Section 4, Definitions, Primary Field of View. (4) AC 25-23 TAWS Terrain Awareness and Warning Systems (5) AC 25-1309-1A System Design and Analysis (6) TSO C-151a, Terrain Awareness and Warning Systems (7) AC 25.1523-1, Minimum Flight Crew & Workload 1.b JAA Documents. (1) AMJ 25.1322, Alerting Systems, dated 12 April, 1991 (2) AMJ 25.1309 System Design and Analysis (3) AMJ 25-11, Electronic Display Systems (4) Patterson, R.D. (1982). Guidelines for Auditory Warning Systems on Civil Aircraft. Cheltenham, England: Civil Aviation Authority paper 82017. 1.c Industry Documents. 1. Edworthy, J. and Adams, A. (1996). Warning Design: A Research Perspective. Bristol, PA: Taylor & Francis. 2. Kuchar, J.K. (1996). Methodology for alerting-system performance evaluation. Journal of Guidance, Control, and Dynamics. 19, 438-444. 3. Parasuraman, R., & Riley, V. (1997). Human and Automation: use, misuse, disuse, abuse. Human Factors, 39, 216-229. 4. Satchell, P. (1993). Cockpit monitoring and alerting systems. Aldershot, England: Ashgate. 5. SAE ARP 4033 (Pilot-System Integration), August 1995 BACKGROUND In the past airplanes have been designed with discrete lights for the alerting function. Now the alerting functions can be integrated with other systems, including electronic display systems, and aural warning or tone generation systems. This AC addresses the aspects of integration including prioritization, commonality between types of alerts, competing simultaneous aural and visual alerts, correlation of aural and visual alerts, potential inhibiting of alerts, and the increased possibility of false or nuisance alerts. FAR/JAR Part 25 Regulations and advisory material often provide references to an alert, such as a warning, to provide awareness of a certain condition that is relevant to the applied rule. Many of these rules were written without recognition of a consistent flight deck alerting philosophy, and may use the term “warning” in a generic sense. This AC/ACJ does not intend to conflict with or replace the intent of those rules, but it is meant to provide standardization of crew alerting terminology that may be used in the development of consistent regulations and advisory material, and consistency to show compliance to existing rules. DEFINITIONS Definitions are written to support the content of this AC and its associated rule. Other regulations may use terms such as “warning” in a manner that is not necessarily consistent with the definitions below. However, the intent of this section is to facilitate standardization of these terms. Advisory The level of alert for conditions that require flight crew awareness and may require subsequent flight crew response Alert A generic term used to describe a flight deck indication meant to attract the attention of and identify to the flight crew a non-normal operational or airplane system condition. Warnings, Cautions, and Advisories are considered to be alerts. Alert Inhibit Application of specific logic to prevent the presentation of the alert. Alert Message A visual alert comprised of text, usually presented on a flight deck display. Alerting Function The aircraft function that provides alerts to the flight crew for non-normal operational or airplane system conditions. This includes Warning, Caution and Advisory information. Alerting Philosophy The principles, guidance and rules for implementing alerting functions within a flight deck. These typically consider: • The reason for implementing an alert • The level of alert required for a given condition • The characteristics of each specific alert • Integration of multiple alerts Attention Getting Cues Perceptual signals (visual, auditory or tactile/haptic) designed to attract the flight crew’s attention in order to obtain the immediate awareness that an alert condition exists. Caution The level of alert for conditions that require immediate flight crew awareness and subsequent flight crew response. Collector Message An alert message that replaces two or more related alert messages that do not share a common cause or effect. Example: A Doors alert collector message is displayed when more than one entry, cargo, or service access door is open at the same time. Communication message A type of message whose initiating conditions are caused by incoming communications, primarily data link conditions. This type of message is not a crew alert. (1) Comm High: A communication message which requires immediate flight crew awareness and immediate flight crew response. (Note: At this time there are no communication messages defined that require immediate flight crew response.) (2) Comm Medium: An incoming communication message which requires immediate flight crew awareness and subsequent flight crew response. (3) Comm Low: An incoming communication message which requires flight crew awareness and future flight crew response. False Alert An incorrect or spurious alert caused by a failure of the alerting system including the sensor. Failure Flag One local means of indicating the failure of a displayed parameter. Flashing Short term flashing symbols approximately 10 seconds or flash until acknowledge. Flight Crew Response The activity accomplished due to the presentation of an alert such as an action, decision, prioritization, search for additional information. Master Aural Alert An aural indication used to attract the flight crew’s attention that is specific to an alert urgency level (e.g. Warning, Caution) Master Visual Alert A visual indication used to attract the flight crew’s attention that is specific to an alert urgency level (e.g. Warning, Caution). Normal Condition Any fault-free condition typically experienced in normal flight operations. Operations typically well within the aircraft flight envelope and with routine atmospheric and environmental condition. Nuisance Alert An alert generated by a system that is functioning as designed but which is inappropriate or unnecessary for the particular condition. Primary field of view Primary Field-of-View is based upon the optimum vertical and horizontal visual fields from the design eye reference point that can be accommodated with eye rotation only. The description below provides an example of how this may apply to head-down displays. With the normal line-of-sight established at 15 degrees below the horizontal plane, the values for the vertical (relative to normal line-of-sight forward of the aircraft) are +/-15 degrees optimum, with +40 degrees up and -20 degrees down maximum. For the horizontal visual field (relative to normal line-of-sight forward of the aircraft), the values are +/-15 degrees optimum, and +/-35 degrees maximum. . Status A specific aircraft system condition that is recognized using a visual indication, but does not require an alert and does not require flight crew response. These types of messages are sometimes used to determine airplane dispatch capability for subsequent flights. Tactile/haptic Information Indication means where the stimulus is via physical touch, force feedback or vibration (e.g. stick shaker). Time-Critical Warning A subset of warning. The highest level of warning for conditions that require immediate flight crew response, to maintain the immediate safe operation of the airplane.Examples of Time-Critical warnings are: • Predictive and Reactive Windshear Warnings • Terrain Awareness Warnings (TAWS) • TCAS Resolution Advisory • Overspeed Warnings • Low Energy Warnings Umbrella Message An alert message that is presented in lieu of two or more alert messages that share a common cause. Example: A single Engine Shutdown message in lieu of the multiple messages for electrical generator, generator drive, hydraulic pump and bleed air messages which would otherwise have been displayed. Unique Tones (Unique Sounds) An aural indication that is dedicated to specific alerts. (e.g. fire bell, overspeed) Visual Alert Information A visual indication that presents the flight crew with data on the exact nature of the alerting situation. For advisory level alerts, it also provides the awareness. Voice Information Means for informing the flight crew of the nature of a specific condition. Warning The level of alert for conditions that require immediate flight crew awareness and immediate flight crew response. GENERAL The purpose for alerting functions on airplanes is to get the attention of the flight crew, and inform the flight crew of specific airplane system conditions and certain operational events that require their awareness. The ability of the alerting function to accomplish its purpose is effected not only by the alert presentation itself, but also by the sensed condition and information processing for which the alert presentation was initiated. The alert presentation, condition sensing and information processing for the alert should all be designed to support the purpose of the alerting function. Only airplane system conditions and operational events that require flight crew awareness to support a flight crew response should cause an alert. Conditions and events that do not require flight crew awareness should not cause an alert. For all alerts which are presented to the flight crew, the action or accommodation for that alert must be either intuitive or a specific procedure must be provided to assist the flight crew in accomplishing corrective or compensatory action. Appropriate flight crew action for flight crew alerts are normally defined by airplane procedures (ex: in checklists), and are trained as part of a flight crew training curriculum or considered basic airmanship. The presentation of all alerting signals should be accomplished using a consistent alerting philosophy. 1.d Alerting Presentation Elements Alerting system presentation elements typically include: • Master Visual Alerts • Visual Alert Information • Master Aural Alerts • Voice Information • Unique Tones (Unique Sounds) • Tactile/haptic Information • Failure Flag Logic should be incorporated to ensure that the alerting system components are coordinated and provide the proper alert presentation format for each urgency level. For example, the onset of the master visual alert should occur simultaneously with the onset of the master aural alert. When practical, the voice information message should be identical to the alphanumeric message presented on the visual information display, but at a minimum the voice and alphanumeric messages should be compatible and readily understandable. Colors used for master caution and master warning should match colors for their respective caution and warning visual alerts. To maintain the effectiveness of voice alerting, the use of voice should be minimized. To maintain the effectiveness of the visual alerting, consistent use of the colors red and amber/yellow must be implemented throughout the flight deck. Failure flags and exceedances do not necessarily need to meet the requirements 25.1322(a)(1). For example, failure flags on primary flight displays have been shown to have sufficient attention getting characteristics and thus do not necessarily satisfy all of the requirements for crew alerts, such as providing attention-getting cues through at least two different senses. 1.e Functional Components for each type of Alert (1) Warning: The alerting system functional components used to accomplish the alerting and informing functions for warnings should include: • Master Visual Alert, AND • Visual Information, AND • Master Aural Alert, or Voice Information or unique tone Note: Voice information may be preceded by a master aural alert It is recognized that in a limited number of cases a master visual and master aural alert may not be required. For example, visual information presented in the pilot’s primary forward field of view may be acceptable in place of a master visual alert if it provides sufficient attention-getting characteristics. Exceptions must be evaluated on a case by case basis. The immediacy of pilot response required for some warning conditions may not be supported by use of the alerting system components described above. Examples of such warning conditions are reactive windshear warning and ground proximity warning. These are typically called “time-critical warnings.” The alerting system components used for indicating these kinds of conditions must support immediate pilot awareness of the specific condition without further reference to other indications in the flight deck. The alerting system functional components used to accomplish the alerting and informing functions for time-critical warnings should include: • Unique voice information and/or unique tone for each condition, AND • Unique visual alert information in both pilots primary forward field of view for each condition. Since, for time-critical warnings, it is expected that the unique visual alert information and the unique voice information or unique tone meets the attention-getting requirements for the condition, then the use of a master visual alert is not required. However, if the master visual alert is used, it should be used to aid in the overall attention-getting characteristics and to obtain the desired flight crew response and should not distract the flight crew from the time- critical condition. 2) Caution The alerting system functional components used to accomplish the alerting and informing functions for cautions should include: • Master Visual Alert, AND • Visual Information, AND • Master Aural Alert, or Voice Information or unique tone Note: Voice information may be preceded by a master aural alert It is recognized that in a limited number of cases a master visual and master aural alert may not be required. For example, visual information presented in the pilot’s primary forward field of view may be acceptable in place of a master visual alert if it provides sufficient attention-getting characteristics. Exceptions must be evaluated on a case by case basis. Some caution alerts are related to conditions that are precursors to potential time- critical warning conditions. In these cases, the alerting system components associated with the caution should be consistent with the components for related time-critical warning. For example, a TCAS II Traffic condition, which can be a precursor to a TCAS II Resolution Advisory condition, may not have an associated Master Caution and is acceptable because the TCAS Traffic voice information alone provides the characteristic of a caution. 3) Advisory The alerting system functional components used to accomplish the alerting and informing functions for advisories should include: • Visual Information - Advisory information may be located in an area where the flight crew is expected to periodically scan for information Note: Advisory information does not require immediate flight crew awareness and therefore does not require an attention getting (master) visual or aural feature Aural or visual information such as maintenance messages, information messages, and other status messages associated with conditions that do not require an alert may be presented to the flight crew, but the presentation of this information should not interfere with the alerting function or its use. 1.f Alerting System Reliability and Integrity The alerting system should be designed to avoid false and nuisance alerts while providing reliable alerts to the flight crew when needed. For establishing compliance of the alerting system with 25.1309, both the failure to operate when required and false operation should be considered. When applying the 25.1309 process to a particular system or function that has an associated flight crew alert, both the failure of the system/function and a failure of its associated alert should be assessed. This should include assessing the effect of a single (common mode) failure that could cause the loss or failure of a system function and the loss of any associated alerting function. When assessing crew alerting system compliance to 25.1309, particular attention should be paid to the following: - Availability of the crew alerting function as a common point to several systems: although the individual assessment of not presenting an alert for a given system when required may lead to a specific consequence, the impact of a larger or a complete failure of the crew alerting function may lead to a more severe consequence, and should be assessed. - Integrity of the alerting system driving the crew's confidence: since the individual assessment of a false or nuisance alert for a given system may lead to a specific consequence, the impact of frequent false or nuisance alerts increases the flight crew’s workload, reduces the flight crew’s confidence in the alerting system, and affects their reaction in case of a real alert. Existing implementations have shown that design of crew alerting systems as an essential system satisfy the two points above, but do not replace the need to show compliance with 25.1309. Management of AlertS 1.g Prioritization The objective of prioritization is to provide the most urgent alert to the flight crew. (1) General Guidelines A prioritization scheme should be established for all alerts presented throughout the flight deck. Prioritization within each category (Warning, Caution, Advisory) may also be necessary. For example, AC 25-23 (TAWS) identifies situations where prioritization within alert categories is necessary. The prioritization scheme, as well as the rationale for prioritization should be documented and evaluated. Documentation should include the results of analysis that shows that any alerts that are delayed or inhibited as the result of the prioritization scheme do not adversely impact safety. (2) Multiple Aural Alerts Aural alerts should be prioritized so that only one aural alert is presented at a time. If more than one aural alert is presented at a time, each should be clearly distinguishable and intelligible to the flight crew. Aural alerts must be prioritized based upon urgency of flight crew awareness and urgency of flight crew response. Normally this means Warnings are prioritized first, followed by Cautions and then Advisories. However, there may be a need to prioritize certain alerts of a lower urgency level over alerts of a higher urgency level depending on phase of flight. When aural alerts are provided, an active alert should be completed before initiating another aural alert. However, active aural alerts may be interrupted by alerts from higher urgency levels if the delay to annunciate the higher priority alert would impact the timely response of the flight crew. If the interrupted alert condition is still active, it may be repeated once the higher urgency alert is completed. (3) Multiple Visual Alerts Since two or more visual alerts can occur at the same time, it should be shown that each alert is clearly recognizable to the flight crew. Visual alert information should be prioritized between levels - Warnings have the highest priority, followed by Cautions and Advisories. When multiple alerts exist in a specific level (ie. multiple Warnings, multiple Cautions), a means for the flight crew to determine the most recent or most urgent alert should be provided. For example, the most recent or highest priority alert may be listed at the top of its own category. This also applies to time-critical alerts that share a dedicated display region. 1.h Alert Inhibits Alert inhibits are used to prevent the presentation of an alert which is inappropriate or unnecessary for the particular phase of operation. Alert inhibits are techniques that can be used to resolve prioritization of multiple alert conditions, alert information overload and display clutter. In many circumstances, alert inhibits should be used to prevent additional hazard due to unnecessary flight crew distraction or response (i.e. during takeoff). Alerts may be inhibited automatically by the alerting system, or manually by the flight crew. The presentation of alert indications should be inhibited under certain conditions where: - - - The alert could cause a hazard if the flight crew was distracted by or responded to the alert. The alert contributes to display clutter The alert provides unnecessary information or awareness of airplane conditions A number of consequential alerts may be combined into a single higher-level alert For certain operational conditions not recognized by the alerting system, a means may be provided for the flight crew to inhibit a potential alert that would be expected to occur as the result of the specific operation (e.g. preventing a landing configuration alert for a different landing flap setting). There should be a clear and unmistakable indication that an alert has been manually inhibited by the flight crew, for as long as the inhibit exists. 1.i Clear/Recall of visual alert messages Clearing visual alert messages from the current display allows the flight crew to remove a potential source of distraction. If a message can be cleared, the system should provide the ability to recall any cleared visual alert message that has been acknowledged where the condition still exists. There should be a means to identify if alerts are stored (or otherwise not in view), either through a positive indication on the display or through normal flight crew procedures. 1.j Considerations for interface or integration with other systems (ex. Checklist, synoptics, switches, discrete lamps) All annunciations and indications used to present an alert should be consistent with wording, color, position, or other attributes they may share. Other information displayed in the flight deck associated with the alert condition should facilitate the flight crew’s ability to identify the alert condition and determine any correct action. Information conveyed by the alerting system should lead the flight crew to the correct checklist procedure to facilitate the correct flight crew action. Some alerts may not have an associated checklist procedure because the correct flight crew action is covered by training or basic airmanship (e.g. autopilot disconnect, time critical warnings). 1.k Color standardization The regulation 25.1322(e) requires that “The colors red and amber/yellow are normally reserved for alerting functions. The use of these colors for functions other than crew alerting must be limited and must not adversely affect crew alerting.” For discrete lights and indicators, the use of red and amber/yellow should be limited exclusively to flight crew alerting functions. The regulation applies to the use of these colors on both alerting systems and non-alerting systems including displays and other indications. Note that a display is not necessarily a single piece of hardware but may include an appropriately partitioned and segregated section/function of a display used exclusively for non-alerting functions. The objective is to limit the use of red and amber/yellow within the flight deck so that these colors always provide an indication of immediacy of response commensurate with the associated hazard. The use of red and amber/yellow for non-alerting functions may also be appropriate in the flight deck. Authorization can be expected if any of the following guidelines are met: A. Red may be used for conditions that require immediate flight crew awareness and immediate flight crew response. B. Amber/yellow may be used for conditions that require immediate flight crew awareness and subsequent flight crew response. C. If the colors red or amber/yellow are proposed to be used in any other way, the applicant should submit rationale to the authorities for their review and approval including the benefits and the following: 1. The use of red and amber/yellow is appropriate to the task and context of use; 2. The proposed use does not affect the attention getting qualities and does not adversely affect the alerting functions across the flight deck. NOTE: Graphical depictions of a single weather phenomenon that use color to represent varying intensity or severity may be used only if the use of red and amber/yellow are consistent with paragraphs A, B, or C above. Examples of already accepted uses of red and amber/yellow related to the paragraphs above include: ƒ Engine and airframe limit indications; ƒ Failure flags; ƒ Electronic checklist elements that correlate to an alert; ƒ Indications that correlate to an associated alert; ƒ Weather radar; ƒ Proximate terrain that correlates to an onboard terrain alerting function. It is appropriate to use red or amber/yellow failure flags and system indicators for failures/exceedances associated with hazard conditions requiring immediate flight crew awareness. In these cases, the color should be selected based on the immediacy of the flight crew response. In other cases, the use of red and amber/yellow is not appropriate. However, it would not be appropriate to use red flag to indicate the loss of weather radar data, because immediate flight crew response is not required. 1.l Suppression of False Alerts Pulling circuit breakers should not be the means for the flight crew to suppress an alert. Certification TEST and evaluation considerations Because alerting systems or systems with alerting functions vary in complexity, level of integration, number of alerts, and types of alerts, these systems may raise unique certification issues. Thus it is recommended that applicants develop a plan to establish and document how issues will be identified, tracked, and resolved throughout the life cycle of the program. Applicants typically use the Certification Plan for this purpose. For addressing human factors/pilot interface issues applicants may use FAA Policy Memo ANM-99-2, Guidance for Reviewing Certification Plans to Address Human Factors for Certification of Transport Airplane Flight Decks. Additionally, the JAA INT/POL/25/14 “human factors aspects of flight deck design” provides guidance to evaluate this type of issues, particularly with new or novel systems or functions. A new harmonized AC/ACJ is also being developed. It is recommended that the applicant document means of compliance with the appropriate regulations, as well as document compliance to and/or divergence from the recommendations in this AC/ACJ. Additionally, rationale should be provided for decisions regarding new or novel features in the design of the alerting system. This will facilitate the certification evaluation in that it enables the Authorities to focus on evaluating areas where the proposed system diverges from the recommended guidance and new or novel features. Thus, areas where the applicant has demonstrated compliance with this AC would typically receive less scrutiny. The type of certification evaluation will vary depending upon the complexity, degree of integration, and specifics of the alerting system or function proposed. The evaluation should include evaluations of acceptable performance of the intended functions, including the human-machine interface, and acceptability of failure scenarios of the alerting system. The scenarios should reflect the expected operational use of the system. The validation of the performance and integrity aspects will typically be accomplished by a combination of the following methods: • Analysis • Laboratory Test • Simulation • Flight Test The certification program should include evaluations of the alerts in isolation and combination throughout appropriate phases of flight and maneuvers, as well as representative environmental and operational conditions. The alerting function as a whole needs to be evaluated in a representative flight deck environment. Representative simulators can be used to accomplish the evaluation of some human factors and workload studies. The level and fidelity of the simulator used should be commensurate with the certification credit being sought and its use should be agreed with the regulatory authority. The assessment of the alerts may be conducted in a lab, simulator or in the actual aircraft. Certain elements of the alerting system may have to be validated in the actual aircraft. The evaluation should be conducted by a representative population of pilots of various background and expertise. Some specific aspects that should be considered during the evaluation(s): • Visual, aural, and tactile/haptic aspects of the alert(s) • Effectiveness of meeting intended function from the human/machine integration, including workload, the potential for flight crew errors and confusion • Normal and emergency cancellation logic and accessibility of related controls • Proper integration with other systems, including labelling • Acceptability of operation during failure modes • Compatibility with other displays and controls • Ensure that the alerting system by itself does not issue excessive nuisance alerts nor interfere with other systems • Inhibition of alerts for specific phases of flight (e.g., takeoff and landing) and for specific airplane configurations (e.g., abnormal flaps and gear) Evaluations may also be useful to verify the chromaticity (e.g., red looks red, amber looks amber) and discriminability (i.e., colors can be distinguished reliably from each other) of the colors being used, under the expected lighting levels. These evaluations can be affected by the specific display technology being used, so final evaluation with flight quality hardware is sometimes needed RETROFIT applicability 1.m Purpose This provides recommendations for the integration of flight crew alerting associated with new aircraft systems into aircraft that currently have a FAR/JAR Part 25 type certificate (legacy aircraft). Many of these systems provide flight deck alerting functionality – This material is provided to give the applicant a means to comply with FAR/JAR 25.1322 without major modification to the existing aircraft flight deck alerting system. Systems upgrades for legacy aircraft should be compatible with the aircraft flight deck alerting philosophy. 1.n Visual Alerts (1) Master Warning System. A determination should be made per section 6.3 of this AC/ACJ if the added system warnings will require activation of an aircraft master warning system. (2) Master Caution System. A determination should be made per section 6.3 of this AC/ACJ if the added system caution will require activation of an aircraft master caution system. (3) The existing aircraft alerting system may not be able to facilitate the integration of additional aircraft systems and associated alerts due to limitations in the system inputs, incompatible technologies between the aircraft and the system being added, or economic considerations. i. The incorporation of an additional master visual function is discouraged. If it is not feasible to interface to the existing master visual function, an additional master visual function may be installed, provided that it does not delay the flight crew’s response time for recognizing and responding to the alert. ii. New alerts should be integrated into the existing aircraft crew alerting system where possible. If these alerts cannot be integrated, individual annunciators or an additional alerting display system may be added. iii. It is permissible for some failure flags not to be integrated in the central alerting system. Thus, a master visual or master aural may not be initiated. The need to iv. Conditions that generate failure flags are not necessarily generating an alert. 1.o Aural Alerts (1) A determination should be made per the guidance of this AC/ACJ, if the added system will require activation of an aural alert. (2) If possible this new aural alert should be incorporated into the existing aural alerting system, if this is not possible, a separate aural alerting system may be introduced provided that all of the following have been considered i. A means is provided to set a prioritization scheme in place between existing aural alerts and the new aural alerts such that each alert is recognized and can be acted upon in the time frame appropriate for the alerting situation. ii. Each individual alert can be understood and acted upon. This may require a demonstration of any likely combination of simultaneous alerts. iii. The material provided in this AC/ACJ should be utilized in determining the prioritization for the integration of new aural alerts with existing aural alerts 1.p Special Considerations for Head-Up Displays (HUDs) Although HUDs , when used as Primary Flight Displays (PFDs), are not intended to be classified as integrated caution and warning systems, they may display alerts such as time-critical warnings. HUDs, when used as PFDs, should provide the equivalent alerting functionality as current head down display (HDD) PFDs. Time critical warnings that require continued flight crew awareness on the PFD should be presented on the HUD (e.g., TCAS, Windshear, and Ground Proximity Warning annunciations). In addition if master alerting indications do not provide sufficient attention to the pilot while using the HUD, the HUD should provide annunciations that inform the pilot of caution and/or warning conditions. Time-critical warning information that is presented on a Head Up Display may include attributes which are different than those presented on a Head Down Display. For example the use of red on a HUD may not be technically feasible and under certain conditions may detract from the attention-getting characteristics of the associated time-critical warning. To the extent that current HUDs are single color devices, cautions and warnings should be emphasized with the appropriate use of attention-getting properties such as flashing, outline boxes, brightness, size, and/or location. Report No. DOT/FAA/RD-81/38, II stresses the importance of preserving the distinguishing characteristics of caution and warning cues. . Where multi-color HUD symbols are used for alerts, consideration should be given to ensure consistency between the HUD and the head down flight displays. Single HUD installations can take credit for the copilot monitoring of head down instruments and alerting systems, for failures of systems, modes, and functions not associated with primary flight displays. Dual HUD installations require special consideration for alerting systems, since it must be assumed that both pilots will be head up simultaneously. If master alerting indications do not provide sufficient attention to each pilot while using the HUD, then each HUD should provide annunciations that direct the pilot’s attention to head down alerting displays. The types of information that should trigger the HUD master alerting display are any cautions or warnings not already duplicated on the HUD from head down primary displays. Appendices Appendix A EXAMPLES FOR THE INCLUSION OF Visual System Elements IN AN ALERTING SYSTEM Examples are included in this AC/ACJ to help the reader through the detailed design of an alerting system. They are based on experience of existing and recommended alerting systems that comply with the rule. The extent to which these examples are applied to a specific certification program will vary, depending on the types of alerts that are presented, and the level of integration associated with an alerting system. The visual elements of an alerting system include: • Master Visual • Visual Information • Time-Critical Warning Visual Information A.1 Master Visual (1) Number & Location A warning master visual alert and caution master visual alert should be provided at each pilot’s station. Master visual alerts for warnings (Master Warning) and for cautions (Master Caution) should be located directly in front of each pilot in their primary field of view. (2) Onset/Duration/Cancellation The onset of a master visual alert should occur in a timeframe appropriate for the alerting condition and the desired response. The onset of a master visual alert should occur simultaneously with the onset of its related master aural alert or unique tone, and its related visual alert information. Any delays between the onset of the master visual alert and its related master aural alert or unique tone, and its visual alert information should not cause flight crew distraction or confusion. The onset of master visual alerts for the same condition (warnings, cautions) should occur simultaneously at each pilot’s station. The master visual alert should remain on until it is cancelled either manually by the flight crew, or automatically when the alerting situation no longer exists. Upon cancellation the alerting mechanisms should be reset to annunciate any subsequent fault condition. (3) Attention-getting visual characteristics In addition to color, steady state or flashing master visual alerts may be used, as long as the method employed provides positive attention-getting characteristics. If flashing is used, all master visual alerts should be synchronous to avoid any unnecessary distraction. (4) Brightness Master visual alerts should be bright enough to attract the attention of the flight crew in all ambient light conditions. Manual dimming should not be provided unless the minimum setting retains adequate attention-getting qualities when flying under all ambient light conditions. (5) Display/Indicator Size and Character Dimensions Any character types, sizes and fonts should be designed so that the master visual alerts are legible and understandable at the pilot’s station where they are installed and should provide suitable attention-getting characteristics. Master visual alerts that subtend at least 1 degree of visual angle have been shown to be acceptable. (6) Color Standard color conventions should be followed for the master visual alerts: • Red for warning • Amber/yellow for caution Master visual alerts for conditions other than warnings or cautions (for example, ATC Datalink alerts) must be in a color other than red or amber/yellow. (7) Test function To comply with the safety requirements of FAR/JAR 25.1309, provisions may need to be included to test/verify the operability of the master visual alerts. A.2 Visual Information (1) Number & Location The number of displays that provide warning, caution, and advisory alerts should be determined by a combination of ergonomic, operational and reliability criteria, as well as any flight deck physical space constraints. The visual information should be located so that both pilots are able to readily identify the alert condition. All warning and caution visual information linked to a master visual should be grouped together on a single dedicated display area. There may be a separate area for each pilot. Advisory alerts may also be presented on the same display area. The intent is to provide an intuitive and consistent location for the display of information. (2) Format A consistent philosophy should be provided for the format of visual information to unambiguously indicate the alert condition. The objectives of the corresponding text message format are to direct the flight crew to the correct checklist procedure, and to minimize the risk of flight crew error. The alerting philosophy should describe the format for visual information. A consistent format should be used. A format philosophy should include the following three elements: • The general heading of the alert, (e.g. HYD, FUEL) • the specific subsystem or location (e.g. L-R, 1-2), and, • the nature of the condition (e.g. FAIL, HOT, LOW) For any given message, the available space on a single page should be able to present the entire text on a single defined area to encourage short and concise messages. Additional lines may be used provided the alert message is clear and unambiguous. If alerts are presented on a limited display area, an overflow indication should be used to inform the flight crew that additional alerts may be called up for review. A memory indication should be used to indicate the number and urgency level of the alerts that have been stored. A “collector message” is a technique that can be used to resolve problems of insufficient display space, prioritization of multiple alert conditions, alert information overload and display clutter. Collector messages should be used where the procedure or action is different for the multiple fault condition than the procedure or action for the individual messages being collected. Example: Non-normal procedures for loss of a single hydraulic system on it’s own is different than non-normal procedures for loss of two hydraulic systems. The messages that are “collected” should be inhibited. An alphanumeric font should be of a sufficient thickness and size to be readable when users are seated at the normal viewing distance from the screen. NOTE: Minimum character height of 1/200 of viewing distance has been shown to be acceptable (e.g a viewing distance of 36 inches requires a 0.18 inch character height on the screen)(DOD-CM-400-18-05, p 12-1) NOTE: Arial and Sans serif fonts have been shown to be acceptable for visual alert text. The size of numbers and letters required to achieve acceptable readability may depend on the display technology used. Stroke width between 10 and 15% of character height appears to be best for word recognition on text displays and extensions of descending letters and ascending letters should be about 40% of letter height. (3) Color Standard color conventions should be followed for the visual information: • Red for warning • Amber/yellow for caution Red should be used for indicating a non-normal operational or non-normal aircraft system condition that requires immediate flight crew awareness and immediate action or immediate flight crew decision. Amber/yellow should be used for indicating a non-normal operational or non-normal aircraft system condition that requires immediate flight crew awareness and future action or future flight crew decision. In addition to red (for warning) and amber/yellow (for caution), a third color may be used to indicate advisory level alerts, to provide a unique and easily distinguishable coding method for all alerting categories. Advisories may be any color except red or green, and preferably not amber/yellow. If amber/yellow is used for both caution and advisory messages, the alerting system should provide a distinguishable coding method. NOTE: Use of red, amber, or yellow not related to caution and warning functions must be minimized to prevent diminishing the attention-getting characteristics of true warnings and cautions Consistent color conventions for alerts within the cockpit should be provided. (4) Luminance The visual alert information should be bright enough so that both pilots are able to readily identify the alert condition in all ambient light conditions. The luminance of the visual alert information display may be adjusted automatically as ambient lighting conditions inside the flight station change. A manual override control may be provided to enable the pilots to adjust display luminance. A.3 Time Critical Warning Visual Information (1) Number & Location Time-critical warning visual information should be provided directly in front of each pilot within their primary field of view. Note: The Primary Flight Display (PFD) is used as a practical and preferred display to use as the time critical warning display. Integration of time critical information into the PFD may vary depending on the exact nature of the warning. For example, a dedicated location on the PFD may be used both as an attention-getting function and a Visual Information Display by displaying alerts such as “WINDSHEAR”, “SINK RATE”, “PULL UP”, “TERRAIN AHEAD”, “CLIMB, CLIMB” etc. In addition, graphic displays of target pitch attitudes for TCAS RAs and Terrain may also be included. (2) Format Time critical warning visual information must be consistent with the corresponding time critical warning aural information. Time critical warning visual information may be presented as a text message (for example, “WINDSHEAR”). Certain time critical warning visual information, including guidance, may be presented graphically (for example, TCAS Resolution Advisory) Text messages that are used for time-critical warning visual information should be red. The time-critical warning visual information should be erased when corrective actions have been taken, or when the alerting situation no longer exists (3) Size An acceptable means of a time-critical display is to subtend at least two square degrees of visual angle, to immediately attract the attention of the flight crews and to modify their habit pattern for responding to non-time-critical alerts. A.4 Failure Flags The use of failure flags on flight deck instruments is a means of indicating failures of displayed parameters or it’s data source. In the sense that these flags indicate failures of airplane systems they have been displayed using colors that are the same as for crew alerts. Failure flags are typically associated with only single instrument displays and as such don’t necessarily satisfy all of the guidance material for flight crew alerts in general. However, in the integrated environment of the flight deck it is appropriate to display instrument failure flags in a color consistent with the alerting system, as part of the alerting function(see paragraph 8d) Conditions that set failure flags may also generate flight crew alerts and the subsequent flight deck indications should be consistent. Appendix B EXAMPLES FOR INCLUSION OF Aural System Elements IN AN ALERTING SYSTEM Examples are included in this AC/ACJ to help the reader through the detailed design of an alerting system. They are based on experience of existing and recommended alerting systems that should comply with the rule. The extent to which these examples are applied to a specific certification program will vary, depending on the types of alerts that are presented, and the level of integration associated with an alerting system. The aural elements of an alerting system include: • Unique tones, including master aural alerts • voice information Each sound should differ from other sounds in more than one dimension (e.g. frequency, sequence, intensity) so that each one is easily distinguishable from the others. B.1 Master Aural Alert and Unique Tones (1) Frequency Aural signals using frequencies between 200 and 4500 Hz have been found to be acceptable. Aural signals composed of at least two different frequencies or aural signals composed of only one frequency that contain different characteristics (e.g. spacing) have been found to be acceptable. To minimize masking, frequencies different from those that dominate background noise should be used (2) Intensity The aural alerting must be audible to the flight crew in the worst-case (ambient noise) flight conditions whether or not the flight crew is wearing headsets (taking into account their noise attenuation characteristics). The aural alerting should not be so loud and intrusive as to interfere with the flight crew taking the required action. The minimum volume achievable by any adjustment (manual or automatic) (if provided) of aural alerts should be adequate to ensure it can be heard by the flight crew if the level of flight deck noise subsequently increases. Automatic volume control is recommended to maintain an acceptable signal-to-noise ratio (3) Number of Sounds The number of different master aural alerts and unique tones should be limited, based on the ability of the flight crew to readily obtain information from each alert and tone. While different studies have resulted in different answers, in general these studies conclude that the number of unique tones should be less than 10. One unique tone for master warning and one unique tone for master caution should be provided. A master aural tone for advisories is not recommended. (4) Onset/Duration It is recommended that an onset and offset of any aural alert or unique tone be ramped to avoid startling the flight crew. • A duration for onsets and offsets of 20-30 ms in the region above threshold has been shown to be acceptable. • An onset level of 20-30 dB above the flight deck ambient threshold has been shown to be acceptable. The onset of the master aural alert or unique tone should occur in a timeframe appropriate for the alerting condition and the desired response. Any delays between the onset of the master aural alert or unique tone and its related visual alert should not cause flight crew distraction or confusion. If more than one source of the master aural alert or unique tone is provided, the master aural alert or unique tone for the same condition should occur simultaneously and synchronously at each pilot’s station. Any timing differences should not be distracting nor should they interfere with identification of the aural alert or unique tone. Signal duration of the master aural alert and unique tones should vary, depending on the alert urgency level and the type of response desired. Unique tones associated with time-critical warnings should be repeated and non-cancellable until the alerting condition no longer exists (e.g. stall warning), unless it interferes with the flight crew’s ability to respond to the alerting condition. Unique tones associated with warnings should be repeated and non-cancellable if the flight crew needs continuous awareness that the condition still exists, to support the flight crew in taking corrective action (ref. 1303.c.(1), Flight and Navigation Instruments, and 25.729.e, Retracting Mechanism) Unique tones associated with warnings should be repeated and cancellable if the flight crew does not need continuous aural indication that the condition still exists (e.g. Fire Bell, Abnormal Autopilot Disconnect). Unique tones associated with warnings should be non-repeatable if the flight crew does not need continuous aural indication that the condition still exists. Master warnings should be repeated and non-cancellable if the flight crew needs continuous awareness that the condition still exists, to support the flight crew in taking corrective action (e.g. FAR/JAR 25.729(e) 2). Master aural warnings should be repeatable until the flight crew acknowledges the warning condition or when the warning condition no longer exists. For master aural cautions and unique tones associated with a caution, the sound should be limited in duration or can be continuous until the flight crew manually cancels it, or when the caution condition no longer exists. Unique tones that are neither associated with a warning nor a caution (e.g. certain advisories, altitude alert, SELCAL), should be limited in duration. (5) Cancellation For caution level alerts, the master aural and unique tone should continue through one presentation and cancel automatically. If there is any tone associated with an advisory, it should be presented once and then cancelled automatically. A means must be provided to reactivate the aurals when canceled. When silenced, the aurals may be capable of re-arming automatically. However, if there is a clear and unmistakable annunciation in the pilot’s forward field of view that the aurals are silenced, manual re-arming is acceptable. B.2 Voice Information NOTE: The purpose for using voice information is to indicate conditions that demand immediate flight crew awareness of a specific condition without further reference to other indications in the flight deck. Effects of using voice information include: - To limit the number of unique tones - To transfer workload from the visual to the auditory channel - To enhance the identification of an abnormal condition, and effectively augment the visual indication without replacing its usefulness - To provide information to the flight crew where a voice message is preferable to other methods - Where awareness of the alert must be assured no matter where the pilot’s eyes are pointed (1) Voice Characteristics The voice characteristics should be distinctive and intelligible. Voice characteristics should include attention-getting qualities appropriate for the level of the alert. (2) Voice Inflection Voice inflection has been used in the past to indicate a sense of urgency. However, an alarming tone indicating tension or panic is not recommended, since it may be inappropriately interpreted by flight crews of differing cultures. Depending on the alerting condition, advising and commanding inflections may be used to facilitate corrective action, but the content of the message itself should be sufficient. (3) Intensity The aural alerting must be audible to the flight crew in the worst-case (ambient noise) flight conditions whether or not the flight crew is wearing headsets (taking into account their noise attenuation characteristics). The aural alerting should not be so loud and intrusive as to interfere with the flight crew taking the required action. The minimum volume achievable by any adjustment (manual or automatic) (if provided) of aural alerts should be adequate to ensure it can be heard by the flight crew if the level of flight deck noise subsequently increases. Automatic volume control is recommended to maintain an acceptable signal-to-noise ratio (4) Onset/Duration The onset of the voice information should occur in a timeframe appropriate for the alerting condition and the desired response. The onset of the voice information should occur simultaneously with the onset of its related visual alert information. Any delays between the onset of the voice information and its related visual alert should not cause flight crew distraction or confusion. If more than one source of the voice information is provided for the same condition, they should occur simultaneously and synchronously at each pilot’s station so that intelligibility is not affected. Voice information associated with time-critical warnings should be repeated and non- cancellable until the alerting condition no longer exists (e.g. terrain warning). However, voice information associated with time-critical warnings should not be repeated if they interfere with the flight crew’s ability to respond to the alerting condition (e.g. windshear warning, TCAS resolution advisory). Voice information associated with warnings should be repeated and non-cancellable if the flight crew needs continuous awareness that the condition still exists, to support the flight crew in taking corrective action. However, voice information associated with warnings should be repeated and cancellable if the flight crew does not need continuous aural indication that the condition still exists (e.g. Cabin Altitude Warning, Autopilot Disconnect). Upon cancellation the alerting mechanisms should be reset to annunciate any subsequent fault condition. For voice alerts associated with a caution, the corresponding voice information should be limited in duration (e.g. TCAS Traffic Advisory, Windshear Caution) or can be continuous until the flight crew manually cancels it or the caution condition no longer exists. (5) Voice information Content The content of the voice information should consider the flight crew’s ability to understand the English language. It may be acceptable to consider the use of languages other than aviation English (either replaced entirely or alternating with a native language). For time-critical warnings, the content and vocabulary of voice information should elicit the immediate (instinctive) corrective action. In order to elicit immediate (instinctive) corrective action, it should provide identification of the condition. In some cases, it may also be necessary to include guidance or instruction information. For warnings and cautions the content of voice information should provide an indication of the nature of the condition. The content should be consistent with any related visual information display. Voice information that use more than one word should be structured to avoid incorrect or misleading information if one or more words are missed (e.g. the word “don’t” at the beginning of a voice message should be avoided). Voice information should be designed to minimize confusion with each other. Date: June 23, 2006 Re: Transport Airplane and Engine Issues Group (TAEIG) Avionics Systems Harmonization Working Group Task 4– Warning, Caution and Advisory Lights Attn: Mr. Craig Bolt, Assistant Chair, TAEIG Dear Mr. Bolt, In accordance with the reference task, the Avionics Systems Harmonization Working Group (ASGWG) is pleased to submit the attached technical report which provides the group’s recommendations for a harmonized revision to AC/AMC 25-11 (herein referred to as “the report”). This report is provided for approval by the TAEIG. In addition to the report, the group would like to bring to your attention the following relevant points: 1) Part of the process included coordination with AIA PITT, to provide technical expertise and input to this draft report. Most of the AIA PITT input is included in this report. However, there are a few items received from AIA PITT which were not incorporated in this report. These are identified as follows: • Section 6.5, Safety Design Guidelines:“Loss of one or more required engine indications on more than one engine”–current draft states this as“remote” however PITT requested that it be listed as“extremely remote” • Section 6.5, Safety Design Guidelines:“Display of misleading required engine indications on more than one engine”–current draft states this as“extremely remote” however PITT requested that it be listed as “extremely improbable” ASHWG Response: With the improvement of display systems, introduction of fully autonomous engine controls, and other mitigating factors, both safety objectives have been accepted in recent certifications. The report’s section on safety design lists these as“Examples of generally accepted safety objectives for engine related failure conditions,” and in the case of engine indications the assumption is made (and clearly stated) that a fully autonomous engine control is provided. The ASHWG position is to provide only guidance (objectives) for certain failure conditions, and that they need to be substantiated (or changed) through the development of an airplane Functional Hazard Assessment. The basis for a higher minimum objective applied to display system indications (e.g. specific scenarios) need to be provided. A suggestion for resolution is to omit these specific safety objectives and point to AMC 901 ( c ) and a previously generated ARAC report for AC 901 ( c )– note that the AC is an ARAC recommended draft since 1998 but it is not yet released. This wording was considered but not incorporated in our draft document. • Appendix B, Powerplant Indications - AIA PITT requested the addition of the following:“No single failure may cause misleading indications on more than one engine. [ref., §25.903(b)].” ASHWG Response: ASHWG rejected this input since there are common mode failures in any display system (e.g. design errors) that can not meet this requirement– for any display indication not just engine indications. In addition no safety objective or failure classification is provided. • Appendix B, Powerplant Indications - AIA PITT requested the addition of the following:“No single failure should cause the loss of all thrust setting parameters on more than one engine [ref. §25.901(b)(2), §25.901(c), §25.1301, §25.1305 §25.1309].” ASHWG Response: ASHWG rejected this input since there are common mode failures in any display system (e.g. design errors) that can not meet this requirement– for any display indication not just engine indications. In addition no safety objective or failure classification is provided. • Appendix B, Powerplant Indications - AIA PITT requested the addition of the following: “For single failures leading to the partial loss of indications on an engine, sufficient indications should remain to allow continued safe operation of the engine [ref. §25.901(b)(2), §25.901(c), §25.903(d)(2)]” ASHWG Response: ASHWG generally accepted this but included the idea of non-recoverable loss of indications. There may be procedures that the flight crew can perform to recover the loss of a display indication (e.g. display reversion). Proposed text that was incorporated in this report: For single failures leading to the non-recoverable loss of any indications on an engine, sufficient indications should remain to allow continued safe operation of the engine [ref. §25.901(b)(2), §25.901(c), §25.903(d)(2)] • Appendix B, Powerplant Indications - AIA PITT requested the addition of the following “Indications required for continued safe operation of the engines, including engine restart, should be displayed after the loss of normal electrical power. “ ASHWG Response: This was considered unnecessary since the failure condition in section 6.5“Loss of one or more required engine indications on a single engine”would need to be met through a system safety assessment that considers many causes, including the loss of electrical power. Therefore this statement is redundant. • One of the CAST objectives assigned to the ASHWG is related to powerplant indications was coordinate with AIA PITT and discussed below (with the complete list of CAST objectives). 2) After the formal task for AC/AMC 25-11 was released, the ASHWG was further tasked with incorporating the recommendations made by the Commercial Aviation Safety Team (CAST), as a result of the report named “Enhancement 34: Implement certain display/alerting features (see next slide) on all new airplane cert and future derivative model planes.” This is driving the current delivery date of this report. Since this is an AC/AMC, the group can not provide wording which requires the inclusion of these enhancements. Our wording reflects the guidance that the ASHWG feels is appropriate for an AC/AMC. Each CAST enhancement item, along with the relevant text from the report (or other response from the ASHWG) is identified below: • Graphical depiction of vertical situation– real time graphical depiction of their vertical situation ASHWG Response: Group position is to not explicitly state (require) VSD, but to include considerations for implementation within the current context of this AC. This report is not prescribing functionality unless required by regulation. Current text included in section 8 of the draft AC/AMC:“Information such as navigation information, weather, and vertical situation display is often displayed on Multi-Function Displays (MFD) which may be displayed on one or more physical electronic displays or on areas of a larger display. When this information is not required to be displayed continuously, it can be displayed part-time.” Current text included in section 7 of the report: Depictions include schematics, synoptics, and other graphic depictions such as attitude indications, moving maps, and vertical situation displays. To avoid visual clutter, graphic elements should be included only if they add useful information content, reduce flight crew access or interpretation time, or decrease the probability of interpretation error. To the extent it is practical and necessary, the graphic orientation and the flight crews’ frame of reference should be correlated. For example, left indications should be on the left side of the graphic and higher altitudes should be shown above lower altitudes.. Graphics that includ