What happened
On 30 October 2000, a Boeing 737-33V, registration G-EZYH, was preparing for a scheduled passenger flight from Liverpool Airport to London Luton. The flight was initially delayed due to adverse crosswind conditions at the destination, but once clearance was received, the crew proceeded with the departure. The weather at Liverpool was characterized by heavy rain and strong, gusting winds.
During the takeoff roll, the crew applied significant left rudder and right aileron to maintain the centerline against the crosswind. As the aircraft accelerated, the flight data indicated a sudden change in the wind component, suggesting the presence of wind shear. Upon reaching rotation speed, the aircraft experienced a rotation rate that was higher than typical for this airframe. As the aircraft lifted off, the nose pitch increased to over 16 degrees, resulting in the rear fuselage making contact with the runway surface.
Following the impact, the crew noticed a secondary bump and later received confirmation from a crew member that the tail had struck the ground. The commander initiated the tail strike checklist and descended to a lower altitude to manage the aircraft's pressurization. The flight proceeded to Luton, where it landed without further incident.
The investigation
The AAIB examined the aircraft's flight data recorder and cockpit voice recorder to reconstruct the takeoff sequence. The investigation focused on the aerodynamic forces acting on the aircraft, specifically the impact of the wind shear and the rotation dynamics. Investigators analyzed the control inputs, noting that the pilot had to use significant physical effort to maintain directional control due to the wind conditions.
Engine performance was also reviewed, noting a brief period of asymmetric thrust at the start of the takeoff roll. Additionally, the investigation looked into whether the deployment of roll spoilers, caused by the necessary aileron input to counter the crosswind, contributed to the pitching moment. Manufacturers reviewed the data and concluded that any spoiler deflection had an insignificant effect on the aircraft's lift or pitching characteristics.
Findings
- The aircraft sustained damage to the underside of the rear fuselage, including skin penetration, deformation of frame chords, and damage to a drain mast.
- A rapid rotation rate exceeding the normal range was a primary factor in the tail strike.
- The presence of wind shear caused a reduction in the headwind component during the critical rotation phase.
- The aircraft reached a pitch attitude of over 16 degrees at a low altitude, exceeding the clearance limits for the 737-300 series.