Boeing has amended its inspection procedures for Boeing 747 engine pylons after the discovery of serious fatigue cracking in a Cathay Pacific 747 pylon. The crack, in the number one engine pylon, was discovered during a post-flight inspection in December 1996. According to an incident report released by the Hong Kong Civil Aviation Department's Accidents Investigation Division, the torque bulkhead at the rear of the pylon had a 200mm crack across its full width following the fatigue failure of both vertical chords. Until the amendment, Boeing's Supplemental Structural Inspection Document (SSID) for the 747 did not include the inspection of Rolls-Royce engine pylons. The aircraft concerned, a 747-200F registered B-HVY, was constructed in 1980.
Source: Flight International
