Ramon Lopez/WASHINGTON DC
The US Federal Aviation Administration has issued a final rule requiring operators of certain older commercial airliners to incorporate repair assessment guidelines (RAG) for work done along the so-called "pressure boundaries", which include fuselage skins, bulkhead webs and door skin, into their maintenance and inspection programmes.
The US aviation agency says the RAGs establish a damage-tolerance-based supplement inspection programme for repairs to detect damage, which may develop in a repaired area, before it degrades the load-carrying capability of the structure below the levels required by airworthiness standards.
The RAGS were first proposed in late 1998, and result from the April 1988 Aloha Airlines incident in which a Boeing 737 suffered major structural damage to its pressurised fuselage during flight. The FAA says airworthiness directives addressing the ageing aircraft issues produced "early fatigue or fail-safe requirements that did not provide for timely inspection of critical structure so that damaged or failed components could be dependably identified and repaired or replaced before a hazardous condition developed."
Each of the RAGs outline repetitive repair inspection intervals for Airbus A300s, BAC One-Elevens, certain Boeing 707/727/737/747s, McDonnell Douglas DC-8/9/10s and Boeing MD-80s, Fokker F28s and Lockheed L-1011 TriStars. The FAA believes the rule will cost original equipment manufacturers nearly $40 million (including $11 million in one-time start-up costs) through to 2022, and aircraft operators $17 million over the same time frame. The spending would go toward revising repair manuals, maintenance training and repair assessment and record keeping.
Deadlines for the RAG programme are either 25 May, 2001 or certain flight cycle limits for each aircraft type, whichever is later.
Source: Flight International
