Accident Details
Probable Cause and Findings
The failure of the left engine high-pressure compressor (HPC) stage 8-10 spool, which caused the main fuel supply line to become detached from the engine main fuel pump and release fuel, resulting in a fire on the left side of the airplane. The HPC stage 8-10 spool failed due to a sustained-peak low-cycle fatigue crack that initiated in the web of the stage 8 disk; the cause of the crack initiation could not be identified by physical inspection and stress and lifing analysis. Contributing to this accident was the lack of inspection procedures for the stage 8 disk web.
Aircraft Information
Analysis
HISTORY OF FLIGHT
On September 8, 2015, about 1613 Pacific daylight time, British Airways flight 2276, a Boeing 777-236ER, G-VIIO, powered by two General Electric (GE) GE90-85BG11 turbofan engines, had started its takeoff ground roll on runway 7L at McCarran International Airport (LAS), Las Vegas, Nevada, when an uncontained engine failure in the No. 1 (left) engine and subsequent fire occurred. The flight crew aborted the takeoff, stopped the airplane on the runway, and evacuated the airplane. The fire was extinguished by aircraft rescue and firefighting (ARFF) personnel after the evacuation ended. The 157 passengers and 13 crewmembers evacuated on the runway via emergency slide/rafts; during the evacuation, 1 cabin crewmember sustained a serious injury, and 19 passengers sustained minor injuries. The airplane was substantially damaged from the fire. The flight was operating under the provisions of 14 Code of Federal Regulations Part 129 from LAS to London Gatwick International Airport (LGW), Horley, England.
Preflight activities were uneventful, and the airplane departed the gate at 1555, 10 minutes ahead of the scheduled 1605 departure. The captain was the pilot flying, and the first officer was the pilot monitoring. A relief pilot was also in the cockpit; he was sitting in the jumpseat, which was behind and between the two pilot seats. The captain taxied the airplane to runway 7L for an intersection takeoff at taxiway A8, which was about 2,662 ft from the runway 7L threshold.
The flight data recorder (FDR) showed that the airplane turned onto the runway heading at 1612:30. The captain advanced the engines to takeoff power 6 seconds later, and the engine N1 (low-pressure compressor), the longitudinal acceleration, and the ground speed increased, consistent with the start of the takeoff roll, at 1612:42. The cockpit voice recorder (CVR) recorded the sound of a "bang" at 1612:51.5, which was followed during the next 2 seconds by a sound similar to an engine spooling down, the engine indicating and crew alerting system (EICAS) aural annunciation "engine fail," and the captain's "stop" callout. During postaccident interviews, the first officer and the relief pilot stated that they heard a "thud" and a "bang," respectively, just before the airplane reached 80 knots, at which time the airplane veered to the left. The FDR showed that, at 1612:53, the left and right master warning lights illuminated (which occurred about the same time as the engine fail warning) and that the thrust levers (as indicated by the left and right throttle lever angle parameters) were moved to idle; 1 second later, the airplane began decelerating from about 77 knots, which was the peak airspeed achieved. The takeoff decision speed (V1) for the flight was 149 knots.
At 1612:58, the CVR recorded a sound similar to the fire warning bell, which lasted for 1.8 seconds, and the FDR showed that the left engine fire warning had illuminated. At that time, the captain stated, "tell [air traffic control (ATC)] we're stopping"; the first officer made this notification at 1613:05. During a postaccident interview, the first officer stated that, as the captain applied wheel braking, he noticed that the thrust levers began moving forward, so he disconnected the autothrottle. (Before reaching 80 knots, the Boeing 777 autothrottles attempt to set takeoff power if the thrust levers are retarded with the autothrottles still engaged.) The captain also reported that he did not use maximum braking because he initially thought that a tire had burst, and the first officer stated that he did not select reverse thrust and deploy the ground spoilers during the rejected takeoff (both pilot monitoring responsibilities) because he was "distracted by the thrust lever increasing."
FDR data showed that the airplane came to a stop at 1613:07 (15.5 seconds after the CVR recorded the sound of the bang); at that time, the CVR recorded the captain's second call for the engine fire checklist, which the first officer acknowledged. (The captain had previously called for the engine fire checklist at 1612:58, when he was also instructing the first officer to notify ATC that the airplane would be stopping on the runway.) At 1613:12, the relief pilot asked if he should make an announcement to the passengers and cabin crew; the captain agreed and indicated that they should "stay there where they are." At 1613:19, the relief pilot used the public address (PA) system to instruct the passengers and cabin crew to "please remain in your seats and await further instructions." About 1 second later, the captain contacted ATC, stating "mayday mayday" and "request fire services," and the tower controller responded that fire services were on the way.
The first officer performed the engine fire checklist memory items. FDR data showed that he moved the left fuel control switch to the cutoff position (1613:20) and pulled and rotated the left fire switch to its stop to discharge the first of two fire extinguisher bottles (1613:27). The engine fire checklist called for the second bottle to be discharged 30 seconds later if the FIRE ENG message still appeared. The first officer selected the electronic checklist on the multifunction display in the cockpit to use the 30-second timer to determine when to discharge the second bottle. At 1613:42, the FDR recorded the second fire extinguisher bottle being discharged (15 seconds after the first bottle), and the CVR recorded the first officer stating, "fire's now gone out." (FDR data show that the left engine fire warning light went out close to the time that the second fire extinguisher bottle was activated.) During a postaccident interview, the first officer stated that he activated the second fire extinguisher bottle earlier than indicated in the checklist because of the need to evacuate.
At 1613:47, the relief pilot asked if he should look outside a window, and the captain agreed. During a postaccident interview, the relief pilot stated that he queried the captain because he (the relief pilot) had seen a "large shadow" outside and above the fuselage. After leaving the flight deck and looking outside a cabin window, the relief pilot observed black smoke with an orange glow and the cabin window glass becoming "crazed." (According to Federal Aviation Administration [FAA] Advisory Circular 25.775-1, "Windows and Windshields," dated January 17, 2003, "crazing is a network of fine cracks that extend over the surface" and is "induced by…exposure to organic fluids and vapors.") The relief pilot told a cabin crewmember to get ready to evacuate and, after returning to the flight deck, stated (at 1615:50), "doesn't look good to me." Also at that time, the CVR recorded a sound similar to the interphone (a call from the cabin to the flight deck), which was not answered.
At 1614:03, the CVR recorded a flight attendant's announcement (over the PA system) that the passengers should remain seated. About 4 seconds later, the captain stated, "I think there's too much fire. I think we've got to get out," which was followed by the first officer's statement, "well [the fire light] says it's gone out," and the captain's statement, "no, we've got to evacuate." At 1614:23.2, the captain announced, over the PA system, "this is an emergency. This is the captain. Evacuate. Evacuate," which occurred 31.7 seconds after the CVR recorded the bang sound. About 4 seconds later, the first officer told the tower controller, "we are evacuating on the runway. We have a fire," and the controller acknowledged this information. The CVR recorded a sound similar to the evacuation alarm at 1614:29, which sounded for 33 seconds. . At 1614:35, the CVR recorded background sounds from the cabin that were consistent with an evacuation, which continued until the end of the recording (at 1615:36). At 1614:42, the captain made a PA announcement to evacuate on the right side of the airplane.
At 1615:03, the relief pilot asked if both engines were shut down. After the first officer stated no, the relief pilot indicated that the right engine needed to be shut down. (During a postaccident interview, the relief pilot stated that he noticed the right engine EICAS indications.) The FDR recorded the right engine shutdown at 1615:06 after the first officer moved the right engine fuel control switch to the fuel cutoff position. According to FDR data, the right engine continued to operate for 43 seconds after the captain commanded the evacuation and about 2 minutes after the airplane came to a stop.
The relief pilot then indicated that the evacuation checklist needed to be performed, and the captain called for the checklist at 1615:13. During a postaccident interview, the captain stated that he did not use the British Airways B777 Flight Crew Operations Manual (FCOM) Quick Reference Handbook (QRH) to "read and do" his evacuation checklist items and instead attempted to perform the checklist items from memory, but he missed the second step, which was to ensure that both engines were shut down. The CVR recorded the first officer performing the steps on the QRH evacuation checklist, one of which was to open the outflow valves (using toggle switches on the cockpit overhead panel) to depressurize the airplane for the evacuation. The first officer stated that he spent between 15 and 20 seconds attempting to open the outflow valves, and FDR data showed that the valves remained in the automatic position, which sets pressurization to a predetermined level. (According to the QRH evacuation checklist, the outflow valves should have been moved to the manual position, which allows a flight crew to control pressurization.)
About the same time as the right engine was shut down, the forward cargo bay fire warning light had illuminated. (FDR data showed that the forward cargo smoke warning became active at 1615:04.) The fire bell sounded in the cockpit for about 2 seconds starting at 1615:22. The captain reporte...
Data Source
Data provided by the National Transportation Safety Board (NTSB). For more information on this event, visit the NTSB Records Search website. NTSB# DCA15FA185