What happened
On 2 March 2019, a DHC-8-402 Dash 8, registration G-JECN, was completing its final commercial flight of the day at Southampton Airport. After landing following a flight from Jersey, the crew performed routine checks and, in accordance with standard operating procedures, shut down the No 1 engine to taxi to the assigned stand using only the No 2 engine.
As the aircraft approached its parking position at a walking pace, the commander attempted to apply the brakes, but the aircraft failed to decelerate. Realizing the brakes were non-functional, the commander instinctively applied full reverse thrust on the remaining engine. Despite this effort, the aircraft struck airport signage, causing impact marks to the forward fuselage and the nose landing gear door. Simultaneously, the tips of the No 2 propeller struck the cover of a ground power unit (GPU) parked near the stand. There were no injuries to the 4 crew members or 59 passengers on board.
The investigation
The AAIB investigation established that the loss of braking capability was directly linked to the state of the aircraft's hydraulic systems. While the brakes functioned normally while both engines were running, the shutdown of the No 1 engine removed the primary source of hydraulic pressure for the No 1 system.
Investigators found that the aircraft's standby (hydraulic) power unit (SPU) had not been activated. This selection is a required step during the approach checklist. Furthermore, the investigation revealed that the after-landing checks were interrupted by the crew's need to perform a routine over-speed governor check, which prevented them from noticing the incorrect hydraulic configuration.
Findings
- The primary cause of the accident was the failure to select the standby hydraulic power unit to the 'on' position.
- The approach checklists were not completed prior to landing, meaning the crew did not verify the hydraulic and fuel pump settings.
- The after-landing sequence was interrupted by an unscheduled over-speed governor check, which diverted attention from the hydraulic system status.
- The commander's instinctive use of reverse thrust, rather than the emergency brake, contributed to the inability to avoid the collision.
- A sense of complacency may have contributed, as the flight was the final sector of a routine day of operations.