Ramon Lopez/WASHINGTON DC
The US Federal Aviation Administration has disclosed a series of safety initiatives covering detailed inspection of wiring and other operating systems for older airliners.
The phased safety project is similar to the agency's ageing aircraft inspection programme, which covers the structures of vintage commercial transports.
The new safety measure complies with the 1997 Gore Report, which recommended expansion of the ageing aircraft programme to cover non-structural systems. The safety project also results from the ongoing investigation into the loss of a 25-year-old TWA Boeing 747-100 in July 1996, where fuel tank wiring problems are suspected to have caused the in-flight explosion.
As written, the Ageing Transport Non-Structural Systems Plan should come as a relief to aircraft manufacturers and the airline industry because it does not call for extensive rewiring of civil transports or other costly measures. Nor does it propose a mandatory retirement age for commercial aircraft.
Administrator Jane Garvey says the FAA will issue a notice of proposed rulemaking (NPRM) by December requiring Part 25 transport-category aircraft manufacturers to demonstrate that their fuel system designs remain safe and prevent possible ignition sources in the fuel tank. Final action on the Special Federal Aviation Regulation is expected in mid-2000.
They must also conduct a design review to determine any additional maintenance practices needed to maintain the integrity of aircraft fuel tank wiring. Tom McSweeny, the FAA's associate administrator for regulation and certification, says the NPRM covers ignition sources. He says other possible safety measures, such as the installation of nitrogen-inerting systems in fuel tanks, remain under study.
Garvey says an improved system for reporting wire failures will be in place next year. Data will be logged at the FAA's National Aviation Safety Data Analysis Center.
Long-term initiatives will improve aircraft maintenance to better address ageing aircraft systems and improve wiring installation drawings and instructions for continued airworthiness. The FAA's ageing aircraft research programme will determine if a service life for aircraft wiring is needed.
Before drafting the plan, a team of technical experts scrutinised five 20-year-old airliners undergoing heavy maintenance to understand how systems age. They concluded that aircraft were airworthy but should undergo improved inspections and maintenance.
Source: Flight International
