Document
NASA Technical M emorandum 8020 6
NASA-T M -80206 1980002 4 876
J
An a lysis of General Aviation
Single-Pilot I FR Incident
Dat a Obtained F rom the NASA
Aviation Safety R eporting System
_o_ ___c_
Hugh P. Berge r on
OCT O BE R 1 9 8 0 LAN._LE' ¢ RE_Er,,q ( IH ,cErqTER L_ _.qA Fi-i o I'- '.A "-',A _v I p1O[_ , v iR._. , l ' l !A
RI / L A
NASA Technic a l M emor a ndum 8020 6
Analysis of General Aviation
Single-Pilot I FR Incident
D a ta Obtained F rom the NASA
Aviation S a fety R eporting System
Hugh P. Bergeron
Langley Re search Center
Ham#ton, Virginia
NI A
National Aeronautics and Space Administration Scien t ific and Technical Information Branch r • Ir L_ I • SUMMARY Aircraft accidents, especially in general aviation single-pilot IFR operations, have increased rapidly in the past ]0 years. These accidents usually result from one or more incidents involving unsafe flight operation.
Although all such incidents do not culminate in accidents, the potential exists. Therefore, an analysis of incident data obtained from the NASA Avia- tion Safety Reporting System has been made to determine the problem areas in general aviation single-pilot IFR operations. The Aviation Safety Reporting System data base is a compilation of voluntary reports of incidents from any person who has observed or been involved in an occurrence which was believed to have posed a threat to flight safety.
This paper examines only those reported incidents specifically related to general aviation single-pilot IFR operations. The frequency of occurrence of factors related to the incidents was the criterion used to define the signifi- cant problem areas and, hence, to suggest where research is needed.
The data were cataloged into one of five major problem areas: (]) Control- ler judgment and response problems, (2) Pilot judgment and response problems, (3) Air traffic control (ATC) intrafacility and interfacility conflicts, (4) ATC and pilot communication problems, and (5) IFR-VFR conflicts. The relative sig- nificance of each of these problem areas was determined by the number of cita- tions corresponding to each area. In addition, several points common to all or most of the problems were observed and reported. These included human error, communications, procedures and rules, and work load.
INTRODUCTION General aviation accounts for approximately ]5 million of the 25 million IFR operations occurring annually in the United States, and Federal Aviation Administration (FAA) forecasts show that by ]988 these operations will almost double to approximately 29 million. Reference ] reports that more than ]00 serious accidents per year (attributable to pilot error) have occurred in the past few years in general aviation single-pilot IFR (SPIFR) operations. This accident rate is expected to increase as the number of general aviation IFR operations increases.
A significant effort is under way within NASA to investigate general avia- tion SPIFR problems. One source of information used as an aid in identifying these problems is the NASA Aviation Safety Reporting System (ASRS) data base.
The ASRS data base is a compilation of voluntary incident reports from any per- son who has observed or been involved in an occurrence which was believed to have posed a threat to flight safety (see refs. 2 to 9). This paper examines ASRS data for incidents related to general aviation SPIFR operations. In par- ticular, all reports of general aviation fixed-wing aircraft flying under IFR in instrument meteorological conditions (IMC) are analyzed. The ASRS data base does not specifically refer to SPIFR operations, but these types of o peration typically involve SPIFR. The period covered by these incident reports extends from May 1, ]978, to January 1, ]979.
The frequen c y of occurrence of factors related to incidents of unsafe flight operations are determined through the analysis of the ASRS data. The implications of these factors are discussed, and specific problem areas are suggested for further investigation and research.
ABBREVIATIONS ARTC air route and traffic control ARTCC air route and traffic control center ASRS Avia t i o n S afe t y Rep o rting S ystem ATC air traffic control ATCT air traffic contr o l tower DABS Discrete Address Beacon System FAA Federal Aviation Administration FSS flight service station IFR Instrument Flight Rules IMC instrument meteor o logical conditions MVFR Marginal Visual Flight Rules SPIFR single-pilot Instrument Flight Rules SVFR special Visual Flight Rules TCA terminal control area VFR Visual Flight Rules DISCUSSION OF ASRS DATA BASE The ASRS, which is operated by NASA in support of the FAA Safety Reporting Program, was designed for the collection, compilation, and storage of incident reports describing occurrences that pose a threat to flight safety. Partic- ipation is voluntary, and data represent the reporter's perception of the occ u rrence.
Facets of the system which may bias the data are (1) the reports are out- come oriented; (2) the reports may not reflect all the facts or details of the incident; (3) the reports may reflect the opinion of the reporter; (4) the reports are, on the whole, unverifiable; (5) the reporter is immune, in most cases, from disciplinary action related to the reported incident; and (6) not all incidents are reported. Even considering these limitations, simple statis- tical information on reported occurrences can be very useful. Obviously, the higher the frequency of the reported occurrence, the more likely it is to be a problem in the national aviation system.
A series of quarterly reports have been published from information provided by the ASRS data base. These reports (refs. 2 to 9) present general statistics on incident reports for all aviation operations encompassed by the ASRS data collected during the period extending from April 15, ]976, to March 31, ]978.
In addition to this broad analysis, several specific problem areas are identi- fied and analyzed. Many of these problem areas have a direct impact on general aviation SPIFR operations. The problem areas discussed in the quarterly reports encompass the data up to that particular point in time at which the report was published.
Repor ted Results A major theme that is expressed, or is evident, in all the ASRS data is the frequent involvement of human error in the incidents reported. References 2 and 3, in particular, emphasize this point. Reference 3, for example, reports that as many as one-half of all the ASRS reports involve human error. The data further imply that human error may be an underlying factor in most, if not all, of the reported incidents. Incidents diagnosed as human error, however, can be misleading. Frequently, aircraft control, ATC facility or other involved sys- tems, were simply not originally optimized from a human factors standpoint.
Therefore, whenever human error is identified as a factor, possible system design changes that might have prevented the incident from happening in the first place should always be considered.
A particular flight phase that was found to be significant (refs. 1, 3, and 4) was the terminal area operations phase. References 3 and 4, for example, show that 50 percent of all the reports refer to incidents occurring in the ter- minal airspace. One-third of all the incidents reported, or two-thirds of those taking place in the terminal airspace, occurred during the approach and landing phase. Also, night operations conducted under restricted visibility during approach and landing posed special problems.
References 4 to 7 also refer to communications as a problem area. This area is particularly amenable to the human factors approach mentioned previ- ously. Misunderstood communications, especially when related to either message confirmation or clearance interpretation, were found to be a major problem. A recurring report theme was the use of procedural shortcuts or nonstandard phraseology; these shortcuts were frequently associated with high density (high work load) operations, communication problems may often lead to other problems, such as altitude errors and flight plan deviations (see ref. 7).
Various other problem areas, many of equal importance to the communi- cations area, were also discussed in the quarterly reports: ATC facility coordination problems (refs. 3, 5, 6, and 9); pilot and / or controller percep- tion problems (refs. 3, 5, and 9); procedural problems (refs. 3, 5, and 9); marginal VFR weather (i.e., VFR-IFR mix, ref. 8); and equipment malfunctions (refs. 4, 5, and 9).
FORMULAT I ON OF I NC I DEN T DATA The ASRS incident data analyzed in this report are limited to the general aviation operations typically involved in SPIFR. Since no specific category in the ASRS data base relates to general avaition SPIFR, the following criteria were chosen in interrogating the data base. All fixed-wing operations under air taxi, charter operations, utility operations, corporate aviation, personal business, pleasure flights, and training flights were selected for the analysis.
All rotary wing operations were deleted. Also, only those flights on either an IFR or SVFR flight plan were used. These criteria produced 79 reports out of the total 2 ] 74 reports collected during the period from May ], ]978 (the begin- ning of ASRS report reformatting) to January ], ]979. Based on their sources, these 79 reports included pilot reports of flight crew errors (]4 reports), AT C reports of flight crew errors (]5 reports), pilot reports of ATC errors (]6 reports), and ATC reports of ATC err o rs (34 reports)_ The incident data reports obtained from the NASA ASRS project office con- sisted of a synopsis and several categories of factors related to the incidents.
These categories included enabling factors, associated factors, descriptors, recovery factors, and supplemental key words. Only two of these, enabling fac- tors and associated factors, were considered relevan t to this study and were used in the analysis.
An enabling factor is an element that is present in the history of an occurrence and without which the occurrence probably would not have happened.
An associated factor is an element that is present in the history of an occur- rence and is pertinent to the occurrence under study, but which does not fulfill the requirements of an enabling factor. Examples of both enabling and associ- ated factors are controller perception, intrafacility co6rdination, pilot dis- cretion, and pilot vigilance. These factors, which are_assigned as enabling or associated by subjective assessment of experts in the particular field related to the incident, are discussed in detail in the following section of the report.
Reference 4 presents additional details on ASRS data formatting.
ANALYSIS OF THE DATA The ASRS synopsis and various categories (see the section "Formulation of Incident Data") assigned to each reported incident were examined by the author to determine the types of problems suggested by the data. This review of the incident reports revealed five major problem areas that were considered to be general aviation SPIFR specific. These problem areas are (]) Controller judg- ment and response problems, (2) Pilot judgment and response problems, (3) ATC intrafa c ility and interfacility co nfli ct s, (4) AT C and pil ot c ommunication problems, and (5) IFR-VFR conflicts.
The factors from two categories, enabling factors and associated fac- tors, were also reviewed. There were 40 different enabling factors and 58 associated factors listed in the 79 incident reports; these factors are described in table I. In the 79 reports, the 40 enabling factors were cited a total of 99 times; the 58 associated factors were cited 82 times. (A factor citing is a listing of that factor in the incident report.) These data imply that more than one factor was cited in some of the incident reports.
After preliminary review, each factor citing was determined to be related to each problem area either directly, indirectly, or not at all . A direct relationship between a factor and a problem area implies an obvious connection with that problem area. An indirect relationship implies a probable but not necessarily definite connection with the problem area. There were also some factor citings that could not be related to the problem area. These deter- minati o ns were made by t he auth o r based o n his analysis of the data. C o nsider, for example, the problem area "Controller judgment and response problems." The enabling factor "ATCT controller perception" is related directly to this problem area, whereas the factor"Federal Aviation Regulation" is indirectly related, and the fact o r "Aircraf_parking procedure" is n o t related at all. This type of classification was determined for both the enabling factors (table II) and the associated factors (table III).
: _ Enabling Factors Table II shows the number of enabling factor citings that are related both directly and indirectly to each problem area. This relationship (also found in table III for associated factors) is used as the basis for the analysis and dis- cussion in this report.
r Table II shows that "Controller judgment and response problems" and "Pilot judgment and response problems" generated large numbers of directly related enabling factor citings.. This reinforces the results noted in the review of the quarterly reports; that is, human error (pilot and controller) is involved in a majority of ASRS i_cidents.
An analysis of the incident data shows that "Controller judgment and response problems" can be primarily attributed to three elements: (I) excessive / impedingprocedural requirements, (2) training / proficiency / experience related mistakes, and (3) equipment operational problems. Table IV lists the problem areas and the primary problem elements within each area. Similarly, "Pilot judgment and response problems" can be attributed primarily to three elements: (1) excessive / impeding procedural requirements, (2) training / proficiency flight infractions, and (3) limitations due to limited avionics. These problem ele- ments can be used to determine the areas that need further research.
Table II also indicates that "ATC intrafacility and interfacility con- flicts" and "ATC and pilot communication problems" were both represented by large numbers of indirectly related enabling factor citings. This once again reinforces the results noted in the quarterly reports. The relatively fewer directly related citings were attributed to the nature of the particular prob- lem. The ASRS data do not always indicate whether or not these particular factors could be classified as relating directly to the incidents. The data are outcome oriented, and the insidious nature of some of the factors is not always apparent. Communication problems, for example, may not always be appar- ent as the cause of an incident. Close scrutiny, however, will frequently show that communication problems frequently started a chain of events that resulted in the reported incident.
Four "AT C intrafacility and interfacility conflicts" problem elements were determined: (1) internal communication problems, (2) hand-off problems, (3) mixed departure and arrival conflicts, and (4) equipment operational prob- lems. Problem elements determined for the "AT C and pilot communication prob- lems" were (I) misunderstood instructions, (2) frequency congestion, (3) exces- sive frequency changes, and (4) excessive / impeding proced u ral requirements.
The last major problem area, "IFR-VFR conflicts," shows characteristics similar to those of the previous two problem areas. A large number of factor citings were related to this problem in an indirect relationship. The number of such citings is disturbing, especially when considering the potentially catastrophic results (midair collisions). The two primary problem elements for this problem area were (1) aircraft proximity at breakout, and (2) IFR flight in VFR and MVFR conditions.
Associated Factor s The asso c iated factors were considered as an independent group of citings.
Table III presents the number of associated factor citings that are related both directly and indirectly to each problem area. The associated factors data were used in two aspects of the analysis: (1) to determine whether additional empha- sis should be placed on the previously discussed problems with respect to the enabling factors (i.e., whether more emphasis should be placed on certain prob- lem areas), and (2) to better interpret underlying implications of some of the problem areas.
"Controller judgment and response problems" showed a large number of both directly and indirectly related associated factor citings. The implication here is that this particular problem is not only easy to determine for some incidents (see enabling factors, table II) but, because of the large number of indirectly related citings, could also be involved in many other incidents. " C ontroller judgment and response problems" appear to be a contributing factor more fre- quently than originally expected. These data suggest that a more in-depth anal- ysis of this problem area is needed.
The results for "Pilot judgment and response problems" were as expected: in contrast to the large number of directly related enabling factor citings (table II), a small number of directly related and a large number of indirectly related associated factor citings were found (table III). These data imply that pilot judgment and response problems are usually easy to pin down.
"ATC intrafacility and interfacility conflicts" and "ATC and pilot communi- cation problems" showed large numbers of citings in the indirectly related cate- gory. These problems are also possibly involved in many of the incidents.
The results are due primarily to the outcome-oriented nature of the data col- lection process. "ATC and pilot communication problems," for example, seldom appear to be the principal causes of an incident (see directly related factors, tables II and III); however, they are frequently possible contributing causes (see indirectly related factors, tables II and III). A fair number of directly related citings (enabling (8), and associated (]6)) were also made for "ATC intrafacility and interfacility conflicts." Internal ATC intrafacility and interfacility problems appear to be fairly prevalent, and should be resolved prior to considering the pilot problems in the ATC system.
The problem area "IFR-VFR conflicts" produced a relatively significant number of associated factor citings, both directly and indirectly related.
The implications discussed earlier (in the "Enabling Factors" section of the report), are also relevant here; that is, the number of citings is disturbing when considering the potentially catastrophic results of this problem area.
DISC U SSION OF RESULTS Table IV, which gives the five major problem areas and the corresponding problem elements, can be used to determine theareas needing further research.
The relative significance of the problem areas can be determined from tables II and III by the number of citings listed for each. Table IV not only defines specific problems that need to be addressed, but also shows the interrelation- ship of these problems. For example, human error is shown to be implicit in most of the problems. This trend emphasizes the need for human factors considerations in both analyzing and solving the problems.
Another element common to the data is the communication problem existing between ATC controllers as well as between ATC controllers and pilots. This human factors problem was present in all areas requiring exchange of informa- tion. C urrent electronic technology suggests various approaches to solving this problem. One promising concept, currently being developed by the FAA, for exam- ple, involves a system called the Discrete Address Beacon System (DABS) (see ref. ]0). DABS was designed as a data uplink / downlink capability independent of normal voice communication channels. This concept requires further testing, but it is a good example of the innovative technology that could be used in solving this problem.
Procedures, both ATC and pilot, appear t o be in need of some revision.
The present aviation system frequently uses procedures which were developed many years ago and often do not meet present-day demands and / or capabilities.
An example is the common set of rules and procedures prescribed for pilots who have a wide range of proficiency and experience and who are operating in an equivalently wide range of aircraft classes and capabilities within the ATC system.
Another fairly co m mon denominator in the data is excessive pilot and con- troller work load. This human factors problem is inherent in many of the present-day pilot and controller tasks, andeven though not always specifically mentioned, it is frequently implied in many of the reported incidents. Methods, techniques, and-systems for reducing work load are drastically needed.
CONCLUDING REMARKS The data in this report were obtained from the ASRS incident data base and were used to define problems and, hence, significant areas for research in the general aviation SPIFR environment. Five general problem areas were identified from the data: (]) Controller judgment and response problems, (2) Pilot judg- ment and response problems, (3) ATC intrafacility and interfacility conflicts, (4) ATC and pilot communication problems, and (5) IFR-VFR conflicts. Several elements were determined for each of these problem areas, and the compilation of these areas and elements can be used to define specific research programs.
The relative severity and, hence the significance of each problem area, is defined and can be used as a reference for determining appropriate SPIFR research efforts.
A review of the problem areas also pinpointed several points common to all or most of the problems. These included human error, communications, pro- cedures and rules , and work load.
It is also significant that the problems determined for SPIFR operations followed the same general trend noted in the NASA ASRS quarterly reports which include data from all categories of aviation operations.
Analysis of the ASRS data at continuing intervals would be beneficial in determining the future direction of problems in the national aviation system.
Langley Research Center National Aeronautics and Space Administration Hampton, VA 23665 August 26, ]980 REFER E N C E S 1. Forsyth, Donna L.; and Shaughnessy, John D.: Single Pilot IFR Opera t ing Problems Determined From Accident Data Analysis. NASA TM-78773, ]978.
2. Billings, Charles E.; Lauber, John K.; Funkhouser, Hallie; Lyman, E. Gene; and Huff, Edward M.: NASA Aviation Safety Reporting System. Quarterly Report Number 76-], April 15, 1976 Through July 14, ]976. NASA TM X-3445, ]976.
3. NASA Aviation SafetyReporting System: Second Q u arterly Report, July 15 - October 14, ]976. NASA TM X-3494, ] 976.
4. NASA Aviation Safety Reporting System: Third Q u arterly Report, Oct o ber 15, 1976 - January 14, ]977. NASA TM X-3546, ]977.
5. NASA Aviation Safety Reporting System: Fourth Quarterly Report, January 15, 1 977 - April 14, ] 977. NASA TM-78433, ]977.
6. NASA Aviation Safety Reporting System: Fifth Quarterly Report, April ] - June 30, ]977. NASA TM-78476, ] 978.
7. NASA Aviation Safety Reporting System: Sixth Quarterly Report, July I, 1977 - September 30, ]977. NASA TM-78511, ]978.
8. NASA Aviation Safety Reporting System: Seventh Quarterly Report, October 1, 1 977 - December 31, ]977. NASA TM-78528, ] 978.
9. NASA Aviation Safety Reporting System: Eighth Quarterly Report, January I, 1978 - March 31, ]978. NASA TM-78540, ]978.
10. Hoffman, William C.; and Hollister, Walter M.: Forecast of the General Aviation Air Traffic Control Environment for the 1980's. NASA CR-137909, ]976.
T_B LE I .- FA CTORS IN THE 7 9 INCIDENT R EPO R TS A N ALYZED (a) E na b ling fa ct ors Ai rc raf t equipmen t pr o bl em/ naviga t lon A T CT gro u nd c on tro ller percepti o n Aircraft parking procedure A T CT local con t roller percep t ion Approach con t roller t echnlque / radlo Conflict aler t ac t ivated ccmn uni cation Depar t ure approach con t roller discre t ion Approach con t roller vigilance Departure approach con t roller perception Arr i val approach c ontroller discre t ion Depar t ure con t roller judgment of traffic Arrival approach controller response spacing Arrival approach con t roller t echnique / Federal Avia t ion Regula t ion ccn T a unl ca t ion Fligh t crew discre t ion Arrival approach con t roller work load Fl igh t c rew pe r cepti o n Arrlval-depar t ure approach controller in t rafacill t y coordina ti on Fligh t crew t echnique / flying A R TC C/ ATCT in t erfacility coordina t ion FSS percep t ion ARTC C con t roller in t erfacili t y coordina t ion Ground ATCT con t roller dis t rac t ion / t ask ARTCC controller judgment of traffic spacing Ins t ruc t or pilo t pe r ception ARTC C con tro l l er per c e pt i o n Main t enance a ct ivi t y ARTCC controller response Mil i tary ATCT controller percep t ion / dis cre t i on / t echn i que A RT CC con t roller t echnique / minlm u m altitude assignmen t policy Nonadherence t o ATC proced u re ARTCC controller vigilance Pilot discre t ion ATCT / arrlval approach con t roller Pilot perception / nonadherence t o AT C pro c edure ATCT con t roller d i scre t ion Pilot t echnique A T CT con t r oll er I n t rafa c i l i t y co o rd i na t i o n Radio communication problem ATCT controller percep t ion ] 0 TABLE I .- C o n c luded (b) Ass oc ia t ed fa c tors Aircraf t maintenan c e pr o bl e m FAA handbook Aircraft under separate ATC jurisdic t ion Facility management policy Airline management policy Facility manning A i rspa c e conf i guration / proximi t y of airspace Facility opera t ional proced u re bo u ndary Familiarity with aircraf t Airspace c onfigurat i on / proximi t y of airway / Olive Branch Rou t e / TCA Federal Avia t ion Regula t ion Airspace configuration / proximi t y of control zone Flight crew perception Airspace configura tl on/proximi t y of multiple Flight progress s t rip airports and / or military airports Frequency conges t ion Airspace configura t ion / proximity of TCA boundary Freq u ency guarded Altit u de heading rules I ntrafacility coordination Approach / ARTC c on t roller interfacility Personnel availability coordina t ion P ilot discre t ion Arrival approach controller in t erfacility coordina t ion Pilot experience level Arrival approach controller work load Pilot perception ARTCC controller perception Pilot response ARTCC controller vigilance Pilot technique, radio communication procedure while in t he air ARTCC interfacillty coordination Proximity of thunderstorm ARTCC intrafacility coordination • Radar coverage limitation .• ATC proced u re Radar equipment pr o blem ATCT controller judg m en t of traffic spacing Radar signal clari t y ATCT c on t roller technique / ATC Radio communication problem ATCT ground con t roller percep t ion See-and-avoid concept ATCT in t rafacility coordination Similar sounding aircraft n_ber ATCT local c ontr o ller work load • •• Taxi proced u re Clearance interpretation TRACON interfacility coordination Clearance readback TRACON intrafacility coordination C cn munic a ti on problem _ Traffic vol _e / conges t ion Departure controller perception Visibili t y reduced / rain Distraction / audio Visibility reduced / haze Distr action / tas k ]] . .J _IB LE II .- RELATIONSHIP BETWEE N P R O B LE M A REAS AND ENABLING F A CTO R GROU P F a cto r s c i t ed Pro bl e m area D ire c tl y r ela t ed I ndi r e c tl y related Con t roller judgment and response problems 56 8 Pilot judgmen t and response problems 30 0 ATC intrafacili t y and interfacili t y conflic t s 8 56 ATC and pilo t c ommunica t ion problems 5 86 IFR-VFR c onflicts 0 38 T AB LE III . - RELA TI ON S H I P BETWEEN PR O B L EM AREA S AND AS S OC I ATE D FA C TOR GR O UP Factors cited Problem area Directly related Indirectly related Controller judgment and response problems 34 _ 32 Pilot judgment and response problems 8 ] 6 ATC intrafacility and interfacility conflicts ]6 49 ATC and pilot communication problems 9 42 IFR-VFR conflicts ]5 24 _%BLE I V.- P R O BLEM AREAS AND P R I MAR Y E LEMENT S Controller judgment and response problems : _ -Excessive / impeding procedural requirements -Training / proficiency / experience related mistakes - E quipmen t opera t i o na l pr o b l e ms Pilot judgment and response problems -Excessive / impeding procedural requirements -Training / proficiency flight infractions -Limitations due to limited avionics ATC intrafacility and interfacility conflicts -Internal communication problems -Hand-off problems -Mixed departure and arrival c onflicts -Equipment operational problems ATC and pilot c ommunication problems -Misunderstanding of instructions -Frequency congestion -Excessive frequency changes -Excessive / impeding procedural requirements IFR-VFR conflicts -Aircraft proximity at breakout "IFR flight in VFR and MVFR conditions r ]3 1 . Report No. 2 . Go v e rn me n t A cc ess i onNo. 3 . Rec ip ient's'Cata l og No.
NASA TM- 80 206 4. T i t l e a n d S ubt i t l e 5 . Re po rt D ate ANALYSIS OF GENERAL AVIATION SINGLE-PILOT IFR Octob e r ] 98 0 INCIDENT DATA OBTAINED FROM THE NASA AVIATION 6. P erfor m ing O rgan i zat i onCode SAFETY REPORTING SYSTEM 7 . A uthor(s) 8. Performing Or gan i zat i on R eport No.
Hugh P. Bergeron L- 1 3548 10 . Work U n i t N o .
9. P e r f ormi n g O rg a n i zationN am e an d Add r ess 5 0 5 - 4 ]-73-01 NASA L an gley Research Cent e r '1 1. Contract or G rant No.
Hampton, VA 23665 13. T y pe o f Report and Period Co vered 1 2 . S p o n sor i ng A g e ncy Na m e and A ddr e s s Technical Memorand u m National Aeronautics and Space Administration Washington, DC 2 0 546 14 Sponsoring A g e nc y Co de 15 , , _ J pp le m e n tary Notes 16 , Ab stract An analysis of data obtained fr o m th e NASA Aviation Safety Reporting System (ASRS) data base has been made to determine problems in general aviation single-pilot IFR operations. The data examined consisted of incident reports involving flight safety in the National Aviation System. Only those incidents involving general aviation fixed-wing aircraft flying under IFR in instrument meteorological condi- tions were included in the analysis. The data were cataloged into one of five major problem areas. The significance of the related problems, and the various underlying elements associated with each are discussed. A review of previous ASRS reports covering several areas of analysis is also included.
r 1 7 . K ey Words (Sugg e sted by A uthor(s) } 18. Distribution Statement Gen e ral a v iation Air traffic control U nclassified - Unlimited Aviation safety Flight crew Aviation incidents IFR Flying safety Subject Category 03 19. S e curity Classif . (of thisr epo rt) 20. S e curity C lassif.(of this pa ge ) 21. No. of P a ge s 22. Pric e Unclassified Unclassified ] 3 A02 For sal e by th e National T e chnical In f ormation S e rvi ce, S pring f ield . V i r g inia 2 2 1 6 1 NASA-Langl ey, 1980
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