A fatal crash at Broome in 2012 has resulted in an airworthiness bulletin for operators of Piper PA-34 Senecas.
The Australian Transport Safety Bureau was unable to determine a causal factor for the crash in July 2012 that killed a commercial pilot on a freight run, but found faults in the aircraft’s fuel selector valves. Both shutoff/selector valves allowed fuel to flow between tanks via cross-feed lines when selected to the OFF position.
CASA airworthiness bulletin AWB 28-016 says ‘The inability to isolate an affected engine from the fuel system, or to make effective use of the cross-feed function in the event of an in-flight engine shutdown, is considered a continuing airworthiness issue.’
The selector valves were found to have deteriorated O-ring seals, which were worn, cracked or shrunk.
AWB 28-016 recommends that owners of PA-34 and other aircraft using Scott fuel valves, such as PA-44 Seminole and PA-23 Aztec modules, perform a detailed functional check of the fuel shutoff and cross-feed system to verify that both fuel selector valves operate correctly. AWB 28-016 recommends that any selector valve found to fail the functional/leakage checks should be replaced before further flight.