Altitude Reporting Equipment and Transponder System Maintenance and Inspection Practices

2/15/17 AC 43-6D Appendix A APPENDIX A. TABLES Table A-1. Abbreviated Correspondence Test Altitude Information Pulse Positions RANGE PULSE POSITION (0 or I in a pulse position indicates absence or presence of a pulse, respectively) INCREMENTS D4 A1 A2 A4 B1 B2 B4 C1 C2 C4 (FEET) -1000 0 0 0 0 0 0 0 0 1 0 -900 0 0 0 0 0 0 0 1 1 0 -700 0 0 0 0 0 0 1 1 0 0 -400 0 0 0 0 0 0 1 0 1 1 -200 0 0 0 0 0 1 1 0 0 1 0 0 0 0 1 1 0 0 0 1 0 0 0 1 1 0 0 0 0 1 0 0 1 1 0 0 0 0 0 1 14800 0 1 1 0 0 0 0 0 0 1 30800 1 1 0 0 0 0 0 0 0 1 Integrity of code lines is ensured through testing at these increments.

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2/15/17 AC 43-6D Appendix A Table A-2. Correspondence Test Altitude Information Pulse Positions RANGE PULSE POSITION (0 or 1 in a pulse position indicates absence or presence of a pulse respectively) INCREMENTS D4 A1 A2 A4 B1 B2 B4 C1 C2 C4 (FEET) -1050 to -950 0 0 0 0 0 0 0 0 1 0 -50 o +50 0 0 0 0 0 1 1 0 1 0 450 to 550 0 0 0 0 0 1 0 0 1 0 950 to 1050 0 0 0 0 1 1 0 0 1 0 1050 to 1150 0 0 0 0 1 1 0 1 1 0 1250 to 1350 0 0 0 0 1 1 1 1 0 0 1450 to 1550 0 0 0 0 1 1 1 0 1 0 1750 to 1850 0 0 0 0 1 0 1 0 0 1 1950 to 2050 0 0 0 0 1 0 1 0 1 0 2550 to 2650 0 0 0 0 1 0 0 0 1 1 2650 to 2750 0 0 0 0 1 0 0 0 0 1 2950 to 3050 0 0 0 1 1 0 0 0 1 0 3950 to 4050 0 0 0 1 1 1 1 0 1 0 5950 to 6050 0 0 0 1 0 0 1 0 1 0 6750 to 6850 0 0 1 1 0 0 0 0 0 1 7950 to 8050 0 0 1 1 0 1 1 0 1 0 9950 to 10050 0 0 1 1 1 0 1 0 1 0 11950 to 12050 0 0 1 0 1 1 1 0 1 0 13950 to 14050 0 0 1 0 0 0 1 0 1 0 14750 to 14850 0 1 1 0 0 0 0 0 0 1 15950 to 16050 0 1 1 0 0 1 1 0 1 0 17950 to 18050 0 1 1 0 1 0 1 0 1 0 19950 to 20050 0 1 1 1 1 1 1 0 1 0 21950 to 22050 0 1 1 1 0 0 1 0 1 0 24950 to 25050 0 1 0 1 1 1 0 0 1 0 29950 to 30050 0 1 0 0 0 0 1 0 1 0 30750 to 30850 1 1 0 0 0 0 0 0 0 1 34950 to 35050 1 1 0 1 1 0 0 0 1 0 39950 to 40050 1 1 1 1 0 1 1 0 1 0 44950 to 45050 1 1 1 0 0 1 0 0 1 0 49950 to 50050 1 0 1 1 0 1 0 1 0 A-2

2/15/17 AC 43-6D Appendix A Table A-3. Test Association Matrix The following table lists appropriate tests to assure system functionality after removal, replacement, or installation of altitude reporting equipment and transponder system components.

COMPONENT DESCRIPTOR TESTs Altimeter Pilot reference. 1. Field elevation verification.

2. Correspondence test.

3. Static leak test.

Altimeter Pilot reference. 1. Field elevation verification.

Matched to encoder prior to 2. Abbreviated correspondence test.

installation. 3. Static leak test.

Altimeter Other than pilot reference. 1. Field elevation verification.

2. Static leak test.

Encoding altimeter Pilot reference. 1. Field elevation verification.

2. Abbreviated correspondence test.

3. Static leak test.

Encoding altimeter Other than pilot reference. 1. Field elevation verification.

2. Correspondence test.

3. Static leak test.

Encoding altimeter Other than pilot reference. 1. Field elevation verification.

Matched to pilot reference altimeter 2. Abbreviated correspondence test.

prior to installation. 3. Static leak test.

Blind altitude encoder Connected to transponder. 1. Correspondence test.

2. Static leak test.

Blind altitude encoder Connected to transponder.

1. Abbreviated correspondence test.

Matched to pilot reference altimeter 2. Static leak test.

prior to installation.

Blind altitude encoder Not connected to transponder. 1. Abbreviated correspondence test (modified).

2. Static leak test.

Combined static probe/air Installed as single component without 1. Single indicated altitude and data computer opening static system. transponder pressure altitude correspondence verification.

Transponder High reliability style connector 1. Transponder test and inspection.

system.

Transponder Non-high reliability style connector 1. Transponder test and inspection.

system. 2. Abbreviated correspondence test.

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2/15/17 AC 43-6D Appendix B APPENDIX B. DEFINITIONS 1. Approved. Unless used with reference to another person, means approved by the Administrator.

2. Blind Encoder (Digitizer). An altitude reporting encoder that is pressure operated, having no altitude display; is not part of a pressure/altitude indicating device or system; does not contain an external means for barometric setting; and may supply altitude reporting information to the air traffic control (ATC) transponder, Global Positioning System (GPS), or other onboard system.

3. Calibrated Datum of the Altimeter. The correction applied via a specific calibration card applicable to a specific altimeter to correct for instrument error (scale error) only.

4. Correspondence. The maximum absolute difference between altimeter display and encoder output for a constant encoder output. The altimeter’s displayed pressure/altitude (referenced to 29.92) compared to encoded altitude output from the blind encoder or encoding altimeter for the entire period (from the moment that the code output changes to a value to the moment the code output changes to the next value while the pressure/altitude is changing).

5. Data. Drawings, sketches, stress analyses, reports, operating limitations, or photographs that support or describe an alteration.

6. Encoding Altimeter (Pressure Altitude). An altitude indicator that displays to the pilot the pressure/altitude sensed by the device and produces an altitude reporting output.

7. Gillham Encoder. An altitude reporting encoder that provides parallel data output employing the Gillham (Grey) code.

8. Indicated Datum of the Altimeter. The altitude displayed by the altimeter when an ideal absolute pressure is applied to the sensing member of the altimeter and not corrected for instrument error (scale error), nor corrected for static source error.

9. Matched Components. An altimeter and a blind encoder that have been tested and calibrated together and, as a combination, meet the requirements of 14 CFR part 91, § 91.411(a).

10 High Reliability Style Connectors. Connectors designed to or meeting military or similar industry standards.

11. Pilot Reference Altimeter. The altimeter normally used to maintain flight altitude.

B-1

2/15/17 AC 43-6D Appendix C APPENDIX C. TSO-C112C MARKING AND PART 43 APPENDIX F CLASS C.1 The Technical Standard Order (TSO)-C112c, Air Traffic Control Radar Beacon System/Mode Select (ATCBS/Mode S) Airborne Equipment, labeling scheme does not match the labeling called out in 14 CFR part 43 appendix F. The new TSO labeling is based on RTCA, Inc. DO-181E, Minimum Operational Performance Standards for Air Traffic Control Radar Beacon System/Mode Select (ATCRBS/Mode S) Airborne Equipment, Section 1.4.6, rather than the labeling that had been defined previously in TSO-C112.

C.2 To assist operators in complying with part 43, the following table shows the relationship between the TSO-C112c (or later version) labeling scheme and the part 43 appendix F requirement. Equipment approved under previous versions of TSO-C112 are not affected and may continue to use the label from the equipment directly. Manufacturers of TSO-C112c equipment are encouraged to include this cross-reference information in their operating guide and maintenance instructions.

Table C-1. TSO-C112C Marking and Part 43 Appendix F Class ATC Mode S Transponder Equipment Part 43, Appendix F Class Reference TSO-C112c (or later version) 14 CFR Part 43 , Appendix F class: Transponder marking: Level 1, Class 1 Class 1A Class 1B, with optional Level 1, Class 2 1090 + 1 MHz reply frequency Level 2, Class 1 Class 2A Class 2B, with optional Level 2, Class 2 1090 + 1 MHz reply frequency Level 3, Class 1 Class 3A Class 3B, with optional Level 3, Class 2 1090 + 1 MHz reply frequency Level 4, Class 1 Class 4 Class 4, except for RF peak output power and suppression, Level 4, Class 2 which should apply Class 3B Level 5, Class 1 Class 4 Class 4, except for RF peak output power and suppression, Level 5, Class 2 which should apply Class 3B Per RTCA Inc., DO-181E, Section 1.4.6—with options noted in Section 1.4.4.

The part 43 marking shown here originated in the original version of TSO-C112.

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2/15/17 AC 43-6D Appendix D APPENDIX D. SECTIONS 91.411 AND 91.413 COMPLIANCE FLOWCHART Figure D-1. Sections 91.411 and 91.413 Compliance Flowchart D-1

2/15/17 AC 43-6D Appendix E APPENDIX E. STATIC PRESSURE SYSTEM PROOF TEST A proof test may be conducted to demonstrate the integrity of the static pressure system in the following manner: E.1 Unpressurized Aircraft. Evacuate the static pressure system to a pressure differential of approximately 1inHg or to a reading on the altimeter 1,000 feet above the aircraft elevation at the time of the test. Without additional pumping for a period of 1 minute, the loss of indicated altitude must not exceed 100 feet on the altimeter.

E.2 Pressurized Aircraft. Evacuate the static pressure system until a pressure differential equivalent to the maximum cabin pressure differential for which the aircraft is type certificated is achieved. Without additional pumping for a period of 1 minute, the loss of indicated altitude must not exceed 2 percent of the equivalent altitude of the maximum cabin differential pressure or 100 feet, whichever is greater.

E-1 Advisory Circular Feedback Form If you find an error in this AC, have recommendations for improving it, or have suggestions for new items/subjects to be added, you may let us know by contacting the Flight Standards Directives Management Officer at 9-AWA-AF B -140-Directives@faa.gov .

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