All Boeing 747 operators will receive a service bulletin (SB) this month detailing inspection procedures for centre-wing fuel tanks, the manufacturer says.
The SB relates to the continuing investigation into the July 1996 crash of a Trans World Airways (TWA) 747 which has "-determined that the centre-wing tank was involved", says Boeing. The investigators say, however, that they still have not determined the ignition source.
Boeing says that it agrees with the US Federal Aviation Administration "...that inspections will be beneficial in providing additional information on the condition of the fuel system equipment".
Ten in-service 747s have already been inspected according to the SB routine, and "no concerns were identified," says the company. British Airways, which co-operated in developing the new SB checklist, confirms: "We have worked with Boeing for a long time [on the centre-wing tank checks] and we have found absolutely no problems in the course of the investigations."
Boeing says that the SB will detail visual inspection on the integrity of wiring and grounding straps, pumps, fuel lines and fittings, and checks on electrical bonding (ie, insulation and the integrity of electrical-distribution systems).
The US manufacturer says: "We will be working with the airlines and the FAA to develop a plan for inspections and, depending on what we see, will determine further actions if needed." The inspection includes 747-400s.
Source: Flight International
