Washington, DC -- National Transportation Safety Board Chairman Mark V. Rosenker today addressed an aviation conference in California reiterating the agency's concern with aging aircraft.
"We have investigated several accidents and incidents that have highlighted the safety implications resulting from aircraft aging and these accidents repeatedly demonstrate the importance of effective airworthiness programs throughout the service life of aircraft," Rosenker said. "With the proper maintenance program, these accidents involving aging aircraft could have been prevented."
During his speech in Palm Springs, California before the Aging Aircraft Conference, he noted that there is no single criterion that defines an aircraft as 'old'. The age of an aircraft depends on a number of factors that include, but are not limited to the chronological age, number of flight cycles, number of flight hours and the environment in which the aircraft operates. Furthermore, determining the overall health of an aircraft is complicated by the fact that individual aircraft components can age differently in different portions of the same aircraft and by the nature of certain aging mechanisms, such as fatigue.
Some common themes identified in each of these accidents involving aging aircraft have been: Unknown service histories as is the case with military, surplus aircraft, and poor fatigue design details. The regulations did not require fatigue analysis for these airplanes. Most older airplanes have no inspection program, and the continued operation of airplanes beyond their useful lifespan.
On April 28, 1988, one person was killed when the top of the fuselage of Aloha Airlines Flight 243 separated from the rest of the hull due to fatigue and corrosion. As a result of the NTSB's investigation, the FAA's Aging Airplane Program was developed in 1991 to focus on regulatory initiatives related to structural fatigue and corrosion.
In 1996, when the center fuel tank of TWA flight 800 exploded, the Board's investigation found that wiring found in the wreckage had numerous cracks in the insulation that were attributed to age, bringing to light the problem of aging systems.
The Safety Board began documenting numerous systems problems in fleet aircraft starting in May of 1997, with the TWA-800 investigation, and continued that documentation when SwissAir flight 111 crashed in September 1998.
In October of 1998, the FAA released the Aging Transport Non-Structural Systems Program a concept based on the 1991 aging structures program that followed the Aloha 737 accident.
However, aging aircraft continue to be a problem. The in-flight separation of a wing from three Forest Service firefighting aircraft occurred within a short timeframe several years ago. Most recently, during the ongoing investigation of a Chalk's Ocean Airways accident in Miami, Florida in December 2005, it was discovered that the wing of a Grumman Mallard seaplane, manufactured in 1947, separated from the aircraft in flight and the resulting accident killed the 20 passengers and crew on board.
"The Safety Board feels that the continued commercial operation of these 50 to 60 year old airplanes that were not certified to the standards of today's modern airplanes is not safe -all passengers should have the same level of safety," Rosenker said. "The FAA should require records reviews, aging airplane inspections, and supplemental inspections for all airplanes operated under Part's 121, 129 and 135 regardless of the year they were type certificated, the number of passengers they carry or their maximum payload, and has issued related safety recommendations to that effect." For more information visit www.ntsb.gov