What happened
On 30 July 2005, a Boeing 757-236, registration G-BMRE, was performing training circuits at Nottingham East Midlands Airport. The flight crew, consisting of a commander, two student co-pilots, and a safety pilot, had been conducting maintenance activities earlier that morning, which included the replacement of the No 3 wheel brake unit.
During the second touch-and-go maneuver, Air Traffic Control notified the crew that flames were visible originating from the right main landing gear. The commander, concerned about the remaining runway distance if a rejected takeoff were attempted, elected to continue the circuit with the landing gear extended to monitor the situation. The commander instructed the student co-pilot to maintain the visual circuit while he prepared to take control for the landing. Upon touchdown, the commander used reverse thrust and the left wheel brakes to bring the aircraft to a halt. While the fire service inspected the aircraft, it was noted that a hydraulic leak had occurred, though no actual fire was found at the scene.
The investigation
An engineering investigation was conducted using the Maintenance Error Decision Aid (MEDA) process. The investigation examined the maintenance work performed during the night shift, which involved changing the brake unit. The inquiry found that the maintenance team had been working under challenging conditions, including poor lighting and frequent interruptions. One engineer was diverted to a duplicate inspection, while another was engaged in a separate greasing task.
It was determined that the maintenance personnel had not re-fitted the end cap to the brake torque rod. Because the lockbolt did not rotate when tightened, the engineers—relying on their familiarity with the task—assumed the end cap was in place. The investigation also noted that the maintenance plan had been altered without consulting the Maintenance Operations Control department, and the work was performed in suboptimal environmental conditions.
Findings
- The absence of the brake torque rod end cap allowed the pin to work free from the assembly.
- During the landing roll, the brake rod detached and struck the ground, severing hydraulic and electrical lines and causing damage to the brake temperature monitoring components.
- The rotation of the brake unit during the rollout caused the steel rod to scrape the runway, likely producing the sparks observed by ATC.
- Inadequate task planning and the presence of peer and time pressure contributed to the error.
- The maintenance task was subject to multiple interruptions and performed in poor lighting conditions.
- The engineers relied on the 'know-how' principle, performing a repetitive task from memory rather than strictly following the manual.