Using models to explain complex systems are useful in giving a visual sense of how elements of these systems interact and affect one another. The cornerstone of Human Factors (HF) theory is the SHELL Model. The human, or in the case of aircraft maintenance, the aircraft mechanic, is the center of this model.
A ten year NTSB study reports that during the last several decades, improvements in aviation safety have made commercial flying in the United States the safest form of transportation. General Aviation (GA), however, has not enjoyed the same safety record. Although GA aircraft log almost twice as many flight hours as do the airlines, the accident rate per 100,000 flight hours for GA aircraft in 2000 is over twenty times greater than the rate for commercial aircraft.
Change is inevitable, but it’s not automatic. Change has to be initiated by someone or something. As the face of aircraft maintenance changes, the regulations that govern the world of aircraft maintenance should be dynamic enough to keep pace with this changing world. The Code of Federal Regulations (CFR) and more specifically the Federal Aviation Regulations (FAR) should be viewed as a “living” document. Offering up changes to these regulations, as maintainers of aircraft, can and should be initiated by the very people who are most intimately affected by them.
Aircraft mechanics, generally speaking, are a humble group. When someone discovers we work in aviation usually the first question is “Are you a pilot?”. Generally, our response is “No, I’m just a mechanic”. As if what we do for a living is something to hang our heads in shame about.
Mechanic working at altitude in an aircraft fuel tank.
Photo: Michael Spinks
How important is a shift/task turnover in aircraft maintenance? Let's take a look at an historical accident investigation that helped change the safety culture in aircraft maintenance. The accident aircraft was an Britt Airways Embraer 120RT, N33701, operating as Continental Express flight 2574 which crashed in Eagle Lake, Texas on September 11,1991 as a result of an in-flight structural breakup, killing all 14 people on board.