What happened
On 5 November 1999, a Boeing 777-200B, registration N784UA, was performing a scheduled public transport flight from London Heathrow to Los Angeles. During the takeoff roll from Runway 27 Right, the crew updated the Flight Management Computer with revised payload weights. As the aircraft accelerated, it encountered a crosswind and a fluctuating headwind component.
As the aircraft approached rotation speed, the airspeed momentarily dropped by approximately 10 knots before recovering. Upon reaching the rotation speed of 161 knots, the pilot initiated the rotation. During this maneuver, the aircraft experienced a significant pitch-up rate. Shortly after liftoff, the crew received an Engine Indered and Crew Alerting System (EICAS) message indicating that the aircraft's tail had struck the runway. Following the event, the crew depressurized the cabin and climbed to a holding pattern over Daventry, where 130,000 lb of fuel was jettisoned to reduce the aircraft's weight for an emergency landing. The aircraft subsequently landed safely at Heathrow with no injuries to the 18 crew members or 256 passengers.
The investigation
Investigators examined the aircraft at the operator's maintenance facility, discovering that the underside of the fuselage had sustained abrasions over a length of 3.65 metres. The examination revealed that the outer skin had been completely stripped away at several frames along the fuselage centerline, and the tail strike sensor had been partially abraded.
Data from the Flight Data Recorder (FDR) was analyzed to reconstruct the takeoff. The investigation found that the rotation rate during this flight was significantly higher than in previous similar takeoffs. Specifically, the pitch rate was recorded at at least 3.5° per second, compared to a standard 2.5° per second. The investigation also identified a technical anomaly in the FDR programming, where a design error caused certain pitch attitude values to be repeated; however, investigators were able to correct these values for the purpose of the report.
Findings
- The primary cause of the incident was an excessive rate of rotation during takeoff.
- A reduction in the headwind component occurred during the rotation phase, which delayed the main landing gear from leaving the runway.
- The aircraft's pitch attitude reached 12.8° while the main gear was still in contact with the runway, exceeding the limits established in the operator's procedures.
- The operator's procedures specifically noted that rapid or excessive rotation could lead to aft fuselage contact, particularly in gusty conditions.