Inadequate maintenance procedures leading to a fuel leak from an injector were behind an 18 November 2011 engine fire on an ATR 72-200 (F-OIQO) in Moorea, French Polynesia.
A report into the incident by France's BEA accident investigation agency concludes that the operator, Air Tahiti, had not correctly checked the tightness of a metal-to-metal coupling at the primary connection of the number 14 injector on the ATR's port Pratt & Whitney Canada PW120 engine.
The coupling is designed to add an additional level of protection in the event of deterioration of either of the connector's two rubber O-ring seals. The BEA report notes that one of these O-rings was cut, allowing fuel to escape and ignite.
No-one was injured during the incident, which took place on the ground shortly after the powerplant was started. No damage to the airframe occurred and it was returned to service the following day.
Pratt & Whitney Canada has recorded 25 incidents of fuel leaks on PW120 engines between January 2003 and August 2010, 10 of which resulted in fires, says the BEA.
Fuel leaks have usually occurred on the number 7 and 14 injectors due to their relative inaccessibility while the nacelle is fitted to the engine, leading to a revision in inspection guidelines by the manufacturer. Air Tahiti was aware of this update, says the BEA.
However, P&WC in February 2012 issued a further service bulletin to prevent this type of incident, which recommends undertaking a number of procedures when the engine is disassembled.