Incident Overview
During a flight at cruise altitude of 33,000 feet, the captain, who was the pilot flying, reported that the takeoff and climb were normal. After level off, the relief pilot left the cockpit for rest. Minutes later, the captain observed the number 2 engine master warning light illuminated, a level 3 alert on the Engine and Alert Display (EAD), and a red light on the number 2 fire handle and fuel shutoff lever. The fire bell did not activate.
Crew Actions
The captain and first officer performed memory and initial action items from the engine fire hard card checklist and shut down the number 2 engine. The captain discharged one fire bottle, but the engine fire light remained illuminated. A second fire bottle was discharged, but the light persisted. The captain requested the relief pilot return to the cockpit and informed Air Traffic Control (ATC) that the number 2 engine was on fire and they intended to land at the nearest suitable field. ATC advised that Charlotte was 35 miles away with a 10,000-foot runway. The crew requested radar vectors and an immediate descent.
During the descent, the aircraft encountered heavy rain, light hail, and moderate turbulence. A bright flash to the left of the nose was observed, possibly a lightning strike. The first officer initiated fuel dumping. The relief pilot and first officer ran checklists. The captain informed the crew to expect an emergency evacuation upon landing.
Approach and Landing
The aircraft was configured for an engine-out approach, and the crew reviewed the loss of a second engine procedure. The approach, touchdown, and landing roll were normal. The aircraft was stopped on the runway. The engine fire indication remained illuminated. The relief pilot noted that fuel dumping was not terminated before landing. After completing evacuation checklist items, the captain ordered an evacuation.
Investigation Findings
Delta Air Lines maintenance personnel examined the number 2 engine. They found that a fire loop had chafed through an adjacent integrated drive generator (IDG) feeder cable inside the engine cowling, creating a direct 115-volt AC connection between the IDG and the fire detection control unit. This electrical short caused the control unit to fail completely, resulting in a false fire warning in the cockpit. No evidence of fire was found in the engine.
Maintenance Background
Boeing Service Bulletin MD11-71-086, issued May 21, 1996, addressed modifying IDG wire harness support brackets. On May 21, 2001, the bulletin was elevated to Alert level, recommending compliance within one year. Delta Air Lines issued Engineering Order in November 2001 to comply, with a deadline of November 2002. All three engines on the accident aircraft were inspected and modified per the order on March 3, 2002. However, on March 28, 2002, the number 2 engine was replaced with an unmodified engine.
Checklist Note
The Delta Airlines descent, approach, and before landing checklists (dated June 30, 2000) required pilots to check the EAD. When fuel dumping is active, a message appears on the EAD.