What happened
On 11 April 2006, a Bombardier DHC8-311 Dash 8, registration G-WOWC, was performing a commercial passenger flight from London Gatwick to Plymouth Airport. The approach to Runway 31 was conducted in challenging weather conditions, characterized by moderate rain, mist, and strong, gusty winds from the south-west.
During the final stages of the approach, the flight crew experienced significant turbulence. At approximately 820 feet, the autopilot was disconnected. Shortly thereafter, the aircraft experienced a sudden drop in airspeed and a nose-down pitch, descending below the glideslope. As the aircraft neared the threshold, the crew perceived a "sinking feeling" and responded by advancing the throttles and pulling back on the control column to arrest the descent rate.
This corrective action, combined with the reduction in airspeed, resulted in a heavy landing. The aircraft's pitch attitude exceeded the safe limit of 6 degrees, causing the tail to make contact with the runway. The incident resulted in no fatalities and no injuries to the 42 passengers or 5 crew members on board, though the aircraft sustained minor damage to a tail strike sensor and its cover.
The investigation
The AAIB examined the aircraft's Flight Data Recorder (FDR) and interviewed the crew to reconstruct the sequence of events. The investigation focused on the aerodynamic changes occurring during the flare and the impact of the pilot's manual inputs. Investigators analyzed the relationship between engine torque, propeller speed, and the aircraft's pitch attitude during the final seconds of the descent.
Findings
- The aircraft was operating in a high-wind environment where windshear likely caused a reduction in indicated airspeed during the final approach.
- The pilot's decision to flare the aircraft at 20 feet above ground level, rather than the recommended 10 feet, contributed to the loss of airspeed.
- The pilot's inappropriate response to reducing airspeed, specifically the combination of retreating the throttles and an aggressive nose-up input, caused the pitch to exceed the 6-degree threshold.
- The reduction in thrust increased drag from the propellers, further destabilizing the approach speed.