What happened
On 15 January 2009, a DHC-8-402 Dash 8, registration G-JECY, was prepared for a commercial passenger flight from Birmingham Airport to Glasgow. During the pushback procedure at Stand 8L, loud and continuous interference occurred on the ground crew interphone, coinciding with the commander's announcement to the passengers. This noise prompted the ground crewman to remove his headset and rely on hand signals to communicate with the cockpit.
As the pushback neared completion, the tug was disconnected. However, the aircraft began to roll backward. To prevent the aircraft from tipping, the commander applied power to arrest the movement, eventually bringing the aircraft to a stop where the right main wheel had moved over the edge of the apron. The aircraft came to rest against a rain gutter. Following the incident, the crew applied the parking brake, shut down the engines, and passengers were transferred to the terminal via bus.
The investigation
The AAIB investigation focused on the breakdown in communication and the sequence of braking applications. Investigators examined the discrepancy between the ground crew's recollection and the flight crew's actions. While the ground crewman believed he had signaled the commander to apply the parking brake, the commander did not recall seeing such a signal. The investigation also reviewed the impact of the interphone interference on the crew's focus during the transition from pushback to engine start procedures.