But company affirms safety of carbon fibre associates
Airbus has re-stated its confidence in composites to the US National Transportation Safety Board (NTSB) inquiry into the American Airlines Airbus A300-600R crash on 12 November. The crew lost control soon after take-off from New York Kennedy, when the tail-fin tore from the fuselage (Flight International, 20-26 November 2001).
Airbus told the NTSB that it was unable to throw any light on how this happened. The manufacturer insists that if damage is not visible to the naked eye then it will not compromise the strength of a composite structure. Furthermore, any defect that might be present will not propagate during the life of the aircraft. Airbus points to over 35 million hours of in-service experience accumulated on monolithic structures since the introduction of carbonfibre-reinforced plastic on the A310-200 in 1982.
Certification static testing of the A300-600R's fin was undertaken in the worst conditions, determined to be 70% humidity and 70ºC (158ºF), and extended to three times the aircraft's 50,000-cycle design life. The stabiliser was tested to "limit load" when one of six retaining points was removed and damage simulated from an uncontained auxiliary power unit failure. The stabiliser was pushed to 130% of "ultimate load" before rupturing.
Meanwhile, the NTSB is presenting recommendations to the Federal Aviation Administration on pilots' use of rudder techniques in "advanced manoeuvres", which may overstress large airliners.
Source: Flight International
