FAA Office of Aerospace Medicine
Civil Aerospace Medical Institute

Report No: DOT/FAA/AM-15/3

Title and Subtitle: Predicting Accident Rates From General Aviation Pilot Total Flight Hours

Report Date: February 2015

Authors: Knecht WR

Abstract: In his 2001 book, The Killing Zone, Paul Craig presented evidence that general aviation (GA) pilot fatalities are related to relative flight experience (total flight hours, or TFH). We therefore ask if there is a range of TFH over which GA pilots are at greatest risk? More broadly, can we predict pilot accident rates, given TFH?

Many researchers implicitly assume that GA accident rates are a linear function of TFH when, in fact, that relation appears nonlinear. This work explores the ability of a nonlinear gamma-based modeling function to predict GA accident rates from noisy TFH data (random sampling errors).

Two sets of National Transportation Safety Board /Federal Aviation Administration (FAA) data, parsed by pilot instrument rating, produced weighted goodness-of-fit estimates of .654 and .775 for non-instrument-rated and instrument-rated pilots, respectively.

This model class would be useful in direct prediction of GA accident rates and as a statistical covariate to factor in flight risk during other types of modeling. Applied to FAA data, these models show that the range for relatively high risk may be far broader than first imagined, and may extend well beyond the 2,000-hour mark before leveling off to a baseline rate.

Key Words: General Aviation, Accidents, Accident Rates,Flight Hours, Modeling, Predicting

No. of Pages: 14