During climb-out from Darwin, passengers on the British Aerospace Bae146 advised the cabin manager that about 3 metres of cable was trailing from the trailing edge of the right wing. After the first officer had conducted a visual inspection, the crew advised Darwin ATC that they had a problem and required a return for landing. Fuel was burnt off to achieve maximum landing weight. Controllability checks found no handling problems with the aircraft, which was landed safely.
An inspection identified the trailing cable as an aileron trim cable (upper). Failure of the cable had occurred at the outboard pulley located at wing rib 14. The cable was found to have failed as a result of significant corrosion between the pulley bank and the wing rear spar. Corrosion was also present on the failed cable coinciding with the location of the inboard pulley at wing rib 14. No corrosion was found on the left-wing aileron trim cables. Previous inspection of the area was reportedly carried out during a 6C check in May 1999, 3,495 flight hours earlier.
The aileron trim cable material was zinc coated carbon steel (MIL-W-83420, Type 1, Composition A). Stainless steel trim cables were not available from the aircraft manufacturer.
No other reported failures of BAe146 aileron trim cables were found in a search of the Civil Aviation Safety Authority major defect and ATSB incident databases. The operator advised that corroded cables and seized pulleys at that location had been recorded on various BAe146 aircraft since 1992. The aircraft maintenance manual required special attention for corrosion during inspection of cable sections in contact with pulleys.