The Air Charter Safety Foundation’s (ACSF) recently completed review of Part 135 incidents and accidents examines the safety record of the industry from 2004 to 2008. To compile the data, the foundation combed through the NTSB accident database and separated revenue flights from Part 91 events, including maintenance, ferry, positioning and instruction.

Because there is no data on the relative flight hours, the study refrains from drawing specific conclusions. Rather, it serves mainly as a statistical breakdown of accidents by aircraft type, phase of flight, flight purpose and weather conditions.
“Our study provides insight in the areas of our industry that deserve deeper evaluation to identify where higher risks actually lie,” said Jacqueline Rosser, ACSF’s executive director. “Without better data on how many hours are flown by aircraft type and mission, both government and industry are unable to make informed choices regarding interventions.” As an example, the study’s authors cited the statistic that during the five-year period under review there were 128 passenger-flight accidents and 112 cargo-flight accidents. However, with the absence of an accurate recording of flight hours per mission–data not collected by either the NTSB or the FAA–it is not possible to determine the ratio of flight hours per accident according to mission category. Citing the crucial need for identifying trends in industry mishaps, the study also called for more consistent language between the NTSB and the FAA in their accident reporting, as well as stronger emphasis by the two agencies on identifying operating categories.

The study found that approximately 65 percent of all revenue flight accidents and 62 percent of non-revenue accidents occurred in VMC. When analyzed by purpose of flight, the majority of revenue-flight accidents came from passenger activities (41 percent), followed closely by cargo flights (nearly 37 percent). Air medical operations constituted only 9.8 percent of revenue-flight accidents. Flights involving transportation to and from oil rigs in the Gulf of Mexico and Alaska on average represented 18 percent of revenue accident flights during the five-year period.

In terms of the phase of flight in which accidents occurred during revenue-generating operations, the percentage of mishaps during cruise, landing and takeoff were surprisingly similar at 24, 22 and 21 percent, respectively, while cruise, landing and approach dominated the accidents by phase in non-revenue flights.

When the 305 revenue-flight accidents were sorted by aircraft type, piston-
powered airplanes accounted for more than 44 percent, while helicopters were involved in nearly 29 percent. Business jets were the smallest segment at 9.5 percent, while turboprops accounted for just over 17 percent.