What happened
On April 20, 2008, a Kalitta Air Boeing 747-209F, registration N704CK, was performing a scheduled cargo flight from Newark, New Jersey, to Brussels, Belgium. While climbing to 4,000 feet after departing Newark International Airport (EWR), the flight crew received a fire warning light and an audible alarm indicating a fire in the No. 3 engine, a Pratt & Whitney JT9D-7Q turbofan.
The crew executed emergency procedures, which included shutting down the No. 3 engine and discharging the first fire suppression bottle. When fire indications persisted, the crew discharged a second bottle, which successfully extinguished the fire. The crew declared an emergency and was vectored to dump fuel to reduce the aircraft's weight for landing. Approximately 95,000 lbs of fuel was dumped over a period of 25 minutes. The aircraft subsequently landed at EWR without further incident. There were no injuries among the three crewmembers and two mechanics on board.
The investigation
Post-fire inspections were conducted by the FAA, Boeing, and Kalitta Air. The engine showed minor heat distress on the right-hand side of the engine core cowl. Investigators focused on the engine's accessory fuel 'raceway,' where they found concentrated heat distress, sooting, and fire damage.
Pressure testing of various lines and hoses in this area identified leaks in three specific components: the total temperature sensor station 2 (TT2) fuel supply hose, the TT2 fuel return hose, and the engine-driven hydraulic pump supply inlet hose. These three hoses were sent to Eaton Aeroquip for examination.
Testing at the manufacturer's facility confirmed that all three hoses had been compromised. Upon removing the fire sleeves from these hoses, investigators found melting and missing pieces of the Teflon core. It was also noted that the fire sleeves had been replaced at some point with a type different from the original manufacturer's specification. Due to the extent of the thermal damage, investigators could not determine which of the three leaking hoses was the initial source of the flammable fluid leak.
A review of the airline's maintenance program showed that there were no specific life limits or required pressure tests for the hydraulic pump supply hose or the TT2 fuel hoses. Maintenance requirements were limited to visual inspections during