What happened
On 19 October 2009, a Boeing 737-300, registration G-CELI, was preparing for a commercial passenger flight from Manchester Airport to Budapest. During the takeoff roll on Runway 23 Right, the aircraft reached a speed of approximately 83 knots when it experienced a sudden and violent swing to the right. The flight crew, noticing the deviation, immediately rejected the takeoff. The aircraft approached the edge of the runway, requiring a combination of nosewheel steering and rudder inputs to return to the centerline, before coming to a stop. The airport fire service attended the scene, and all 119 passengers and 5 crew members were safely disembarking without injury.
The investigation
The AAIB investigation focused on the cause of the sudden lateral movement. While the flight crew did not recall making a significant rudder input, Flight Data Recorder (FDR) analysis revealed a large right rudder pedal input occurred just before the swing. This was followed by a large left rudder input as the crew attempted to correct the heading. A manufacturer-led desktop simulation confirmed that the aircraft's behavior, including the recorded lateral acceleration, was consistent with the observed rudder pedal movements.
Investigators also reviewed the maintenance history of G-CELI, noting a pattern of directional control issues during landing rolls in previous months. While a leaking steering metering valve was identified and subsequently replaced, testing indicated this leak was not significant enough to cause the takeoff incident. Further inspections of the braking, flap, and tire systems revealed no faults.
Findings
- The sudden rightward swing was caused by a large right rudder pedal input.
- Flight recorder data showed the rudder deflected to full travel, despite the crew not recalling such an input.
- The aircraft had a documented history of intermittent directional control difficulties, though these were previously noted only during the landing phase.
- A leaking steering metering valve was discovered, but it was not determined to be the cause of the takeoff excursion.