What happened
On 22 December 2017, an EMB-145EP, registration G-CKAG, was performing a commercial passenger flight from Bristol to Frankfurt and back. During the return approach to Bristol Airport in low visibility conditions, the flight crew experienced several interruptions due to ATC instructions and communications.
During the descent, the pilot flying intended to deploy the speed brake to manage the aircraft's altitude. However, the crew inadvertently selected the emergency/parking brake instead. During the approach checklist, the commander even verbally stated "park brake" instead of "seatbelt sign," a slip likely caused by the brake being engaged.
Upon touchdown on Runway 27, the aircraft experienced an unusually rapid de-rotation. The pilot found it difficult to maintain directional control, and the aircraft began to drift. During the landing roll, the thrust levers were advanced, which reduced deceleration and exacerbated the deviation. The aircraft eventually left the paved surface and traveled approximately 120 m onto the grass. There were no fatalities and no injuries to the 22 passengers or 3 crew members, though the aircraft sustained damage to the landing gear fairing, wheel rims, and tyres.
The investigation
The AAIB examined flight data from the FDR and CVR, alongside airfield CCTV and radar records. The investigation established that the main wheels were locked upon touchdown because the parking brake was set. This prevented the wheels from rotating normally, leading to the rapid de-rotation noted by the crew.
Investigators also looked into the cockpit environment, noting that the crew was managing multiple tasks and interruptions. The investigation found that the parking brake indicator light on this specific aircraft was positioned in a way that was not easily visible to the pilot in the right seat. Furthermore, the investigation noted that the addition of forward thrust during the roll likely caused the aircraft to exit the runway, as the aircraft might have remained on the pavement had the thrust remained at idle.
Findings
- The primary cause of the accident was the inadvertent selection of the Emergency/Parking brake instead of the speed brake.
- A high workload and frequent cockpit interruptions prevented the crew from noticing the error during the approach.
- The advancement of thrust during the landing roll contributed to the loss of directional control and the subsequent runway excursion.
- The physical design of the parking brake handle and the placement of the indicator light did not serve as effective risk controls in this instance.
Safety action
- The operator has revised its Landing Checklist to specifically require the handling pilot to confirm that the parking brake is in the off position.