Accident Factors in Sport Aviation: Epidemiology for Ultralights and Gyroplanes in the US for the Last 20 Years


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I gave this presentation at the 50th Anniversary Conference of the European Association for Aviation Psychology in September, 2005

Advisors: Alex de Voogt and Robert van Doorn

The critique I got on this presentation was that I misused the terms active and latent failures, which I applied loosely in this paper. This has been rectified in my follow-up paper "Gyroplane Accidents 1985-2005: Epidemiological Analysis and Pilot Factors in 223 Events," available here:

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  • This presentation comprises: A quick introduction to our research A short overview of this project’s results Focus points for future research A question-and-answer session
  • Sport aviation refers to aviation for recreational purposes like sightseeing or pleasure flying Falls under General Aviation , as opposed to Commercial or Military Aviation Most such aircraft are small and light What sets sport aviation apart : Aircraft are privately owned Maintenance is funded and conducted privately , not by companies Regulations governing Sport Aviation leave abundant freedom , as FAA mostly expects self-regulation
  • This study focused on the active and latent failures relevant to the accidents. These concepts come from James Reason , and Active failures directly cause accidents, examples: “collision with other aircraft” or “engine failure” Latent failures contribute to the occurrence of active failures, examples: “maintenance neglected” or “unclean fuel tank”
  • This project intends to provide an epidemiology of accident factors for sport aviation The data come from accident reports downloaded from the US NTSB database. Form data provided information like pilot certification, date, location, etc. Narrative data provided contextual information like cause of accident, surrounding circumstances, etc. The data were analyzed using Pearson’s Chi-square on 2-by-2 crosstabs
  • Ultralights and gyroplanes are light sport aircraft Light weight low-powered Simple construction
  • Here we compare some basic results between the aircraft types: There were many more reported gyroplane accidents than ultralights Both types had pretty much the same percentage of fatal accidents Ultralights seemed to be destroyed more often than gyroplanes, but Loss of control as an active failure was much more prevalent in the gyroplanes sample The percentage of gyroplane accidents involving pilot error as a latent error is more than triple that of the ultralight sample Over half of the accidents in both samples involved pilots with less than 40 flying hours in the accident aircraft
  • Here are some significant relationships found in both samples: Pilots with less than 40 make/model hours Lost control significantly more often than other pilots Were involved in significantly more fatal accidents than other pilots Destroyed their aircraft significantly more frequently than other pilots Pilot error Was significantly the highest contributing factor to loss of control Was the most frequent latent failure by far in both samples
  • To deeper understand sport aviation accidents and prevent them more effectively, future research should focus on: Asking why So many inexperienced pilots fly Percentages of fatal accidents are so high Pilot error is so much more prevalent in gyroplanes than in ultralights Asking what Kinds of errors sport pilots actually make Can be done to prevent such errors Developing an analysis framework for sport aviation, like HFACS or TEM Conducting similar research in Europe Determining what role organizational factors play in sport flying clubs and organizations
  • Questions?
  • Thank you for your attention, please have a look at our colleagues’ posters!
  • Accident Factors in Sport Aviation: Epidemiology for Ultralights and Gyroplanes in the US for the Last 20 Years

    1. 2. Quick Overview <ul><li>Quick introduction </li></ul><ul><li>Short results overview </li></ul><ul><li>Focus for the future </li></ul><ul><li>Take Questions </li></ul>
    2. 3. Sport Aviation <ul><li>General aviation for recreational purposes </li></ul><ul><li>Small aircraft </li></ul><ul><li>Important distinctions: </li></ul><ul><ul><li>Privately owned </li></ul></ul><ul><ul><li>Privately maintained </li></ul></ul><ul><ul><li>Relaxed regulations </li></ul></ul>
    3. 4. This Project <ul><li>Main focus: Active and latent failures </li></ul><ul><li>Adapted from Reason (1990)’s Swiss Cheese Model of Human Error </li></ul>
    4. 5. This Project <ul><li>Epidemiology of accident factors </li></ul><ul><li>Source: US NTSB* accident reports from 1985 to 2005 (20 years) </li></ul><ul><ul><li>Form data </li></ul></ul><ul><ul><li>Narrative data - active/latent failures </li></ul></ul><ul><li>Statistics: Pearson’s χ² on 2x2 Crosstabs </li></ul><ul><li>Aircraft studied: ultralights and gyroplanes </li></ul>* United States National Transportation Safety Board
    5. 6. Light Sport Aircraft <ul><li>1 or 2 seats </li></ul><ul><li>Single Rotax engine </li></ul><ul><li>Under 680 kg </li></ul><ul><li>Max. airspeed: 120 knots (220 km/h) </li></ul>
    6. 7. Individual Results 61.4% 55.2% % Pilots with less than 40 make/model hours 48.2% 14.9% % Pilot error involved 54.5% 38.8% % Loss of control 34.5% 46.3% % Aircraft destroyed 40% 34.3% % Fatal Accidents 220 67 N Gyroplanes Ultralights
    7. 8. Significant Relationships <ul><li>Pilots with less than 40 make/model hours: </li></ul><ul><ul><li>Lost control significantly more often </li></ul></ul><ul><ul><li>Died significantly more often </li></ul></ul><ul><ul><li>Destroyed their aircraft significantly more often </li></ul></ul><ul><li>Pilot error </li></ul><ul><ul><li>Significant highest latent failure involved in loss of control </li></ul></ul><ul><ul><li>Most frequent latent failure by far in both samples </li></ul></ul>
    8. 9. What’s Next? <ul><li>Ask why </li></ul><ul><li>Ask what </li></ul><ul><li>Develop an analysis framework </li></ul><ul><li>Conduct same research again </li></ul><ul><li>Determine organizational factors </li></ul>
    9. 10. Questions?
    10. 11. References - Thank you! <ul><li>Howell, D. C. (2002). Statistical Methods for Psychology (5th ed.). Duxbury: Pacific Grove. </li></ul><ul><li>Markowski, M. A. (1982). Ultralight Aircraft: The Basic Handbook of Ultralight Aviation (2nd ed.). Hummelstown: Ultralight Publications Inc. </li></ul><ul><li>National Transportation Safety Board. (2006). NTSB Aviation Accident Database Query [Electronic Version]. Retrieved 31 May 2006 from </li></ul><ul><li>Pagán, B., de Voogt, A. J., & van Doorn, R. R. A. (2006). Ultralight Aviation Accident Factors and Latent Failures: A 66-Case Study. Aviat Space Environ Med, 77 , 950-952. </li></ul><ul><li>Popular Rotorcraft Association Board of Directors. (2002). Safety Report: Gyroplane Accident Causes per NTSB Reports [Electronic Version]. Retrieved 17 May 2006 from </li></ul><ul><li>Reason, J. (1990). Chapter 7: Latent errors and system disasters. In J. Reason (Ed.), Human error (pp. 173-216). Cambridge: Cambridge University Press. </li></ul><ul><li>Wiegmann, D. A., & Shappell, S. A. (2001). Human Error Perspectives in Aviation. The International Journal of Aviation Psychology, 11 (4), 341–357. </li></ul>