What happened
On 7 October 2022, a Beech 400A, registration N709EL, was performing a private flight from East Midlands Airport to Newquay Airport. During the initial takeoff roll, the commander noted a slight hesitation in acceleration at approximately 95 kt, though the aircraft continued to climb normally after liftoff.
While in flight, the commander noticed the parking brake handle was not fully pushed in. Upon investigation, it was realized that the parking brake had been left with partial pressure applied during the takeoff run. This had caused the brakes to heat significantly during acceleration.
Upon landing at Newquay, the aircraft experienced much greater deceleration than usual immediately after touchdown. The crew applied reverse thrust and speed brakes, but the aircraft began to drift towards the right side of the runway. The aircraft eventually came to rest at a 45-degree angle to the centreline. The mainwheel tyres were found to be fully deflated and smoke was visible from the wheels, though no fire occurred. There were no injuries to the two crew members or the single passenger.
The investigation
Investigators examined the aircraft's braking system and found that both brake units had seized and the thermal relief plugs (fuse plugs) in the wheel hubs had melted. The investigation established that the parking brake handle's travel from the 'on' to 'off' position was only 21 mm, meaning a small error in handle position could leave the brakes partially engaged.
Further examination of the takeoff roll revealed that the commander likely applied only enough toe brake pressure to prevent the aircraft from rolling forward on the uphill gradient at the holding point. Because the aircraft lacked a cockpit light or caption to indicate the parking brake status, and provided no aural warning when takeoff power was applied, the crew was unaware the brakes were still partially engaged.
Findings
- The rapid deceleration and tyre deflation were caused by the brakes being heated during takeoff, which subsequently melted the fuse plugs and/or caused the brakes to seize.
- The parking brake was left partially applied during the takeoff roll.
- The lack of a cockpit indication or warning system to alert the crew that the parking brake was engaged contributed to the incident.
- The 'Before Takeoff' checklist lacked a specific item to verify the release of the parking brake.
Safety action
- The AAIB has issued Safety Recommendation 2024-007, recommending that Textron Aviation Inc. amend the checklists for the Beech 400 series to include a 'release parking brake' item in the 'Before Takeoff' checklist.