Alan J. Stolzer

A comparison of special category light-sport and corresponding type-certificated aircraft safety

INTRODUCTION The special category light sport airplane (light sport) sector of general aviation has grown 10-fold in as many years with solo operations requiring only a sports pilots certificate. With little research on light sport airplane safety, the study objective was to compare light sport and type-certificated airplane accident rates. METHOD Accidents were identified from the National Transportation Safety Board database. Statistics employed Poisson distribution/proportion analyses/Mann-Whitney U-tests. RESULTS For the 2009-2015 period, the light sport airplane accident rate (fatal/non-fatal combined) was >15-fold higher than comparable type-certificated aircraft, undiminished over time. The excessive light sport airplane accident rate was associated with inferior airman experience (time-in-type, certification). Mishaps were most frequent during landing (40%) and, of these, nearly half were due to a deficiency in the flare. There were a dis-proportionate number of trainees involved in landing accidents compared with mishaps for other phases of operations. CONCLUSION Towards improving safety, additional light sport training with emphasis on landings and a focus on the flare and directional control is warranted. PRACTICAL APPLICATION In the confines of the present study considering that landing mishaps, the most common accident cause, are often related to deficiencies in the flare and loss-of-directional control, instructors should ensure that airmen have mastered these aspects of landing and, for trainees, acquired the appropriate visual monocular cues.

Causes and Trends in Maintenance-Related Accidents in FAA-Certified Single Engine Piston Aircraft

The accident rate for general aviation remains high. While most general aviation accident studies have been pilot-focused, there is little research on the involvement of aircraft maintenance errors. We undertook a study to answer this question. The Microsoft Access database was queried for accidents occurring between 1989 and 2013 involving single engine piston airplanes operating under 14CFR Part 91. Pearson Chi-Square, Fisher’s Exact Test, and Poisson probability were used in statistical analyses. The rate of maintenance-related general aviation accidents was 4.3 per million flight hours for the 1989–1993 period and remained unchanged for the most recent period (2009–2013). Maintenance errors were no more likely to cause a fatal accident than accidents unrelated to a maintenance deficiency. Inadequate/improper maintenance (e.g., undertorquing/non-safetied nuts) represented the largest category causal for, or a factor in, accidents. Maintenance errors involving the powerplant caused, or contributed to, most accidents, but did not carry a disproportionate fraction of fatal accidents. Noncertified airframe and powerplant (A&P) aircraft maintenance technicians (AMTs) performed maintenance on 13 out of 280 aircraft involved in maintenance-related accidents. While there is current concern as to the safety of the aging general aviation fleet, the fraction of fatal accidents for aircraft manufactured prior to 1950 was not higher than those manufactured more recently. We conclude that the general aviation accident rate related to maintenance deficiency, while low, is static. Increased emphasis should be placed on tasks involving torquing and improper rigging as well as maintenance related to installation/assembly/reassembly. Whether a maintenance error decision aid plan, shown to reduce maintenance errors at airline facilities, would benefit general aviation deserves consideration.