What happened
On 7 April 2004, a Raytheon 390 Premier 1, registration N200PR, was involved in a serious accident at Blackbushe Airfield, Hampshire. The flight, which was a private operation, began with a flight from Luton to Humberside, followed by a leg to Dublin. During the flight to Dublin, the pilot encountered several technical issues, including the inability to retract the landing gear and various system failure indications, specifically affecting the lift dump and anti-skid systems.
Due to insufficient fuel to continue to Dublin, the pilot diverted to Farnborough to meet maintenance engineers. After a successful landing at Farnborough, the aircraft was flown to Blackbushe for further technical investigation. During the approach and landing at Blackbushe, the pilot experienced a lack of effective braking. In an attempt to avoid an overrun, the pilot initiated a go-around, but the aircraft failed to achieve sufficient rotation speed and continued down the runway. The aircraft eventually left the paved surface, crossed a taxiway, and struck an embankment. The impact caused the wings to detach from the fuselage and the aircraft to come to rest on its side. There were no fatalities, and the pilot escaped through the emergency exit.
The investigation
The AAIB investigation examined the aircraft's flight data, including the Cockpit Voice Recorder and the Enhanced Ground Proximity Warning System. Investigators focused on the mechanical cause of the initial landing gear and system failure indications. They discovered that a support bracket for the right main landing gear weight-on-wheels switch had suffered a pre-impact failure. This mechanical failure was responsible for the erroneous indications regarding the landing gear, lift dump, and anti-skid systems.
Furthermore, the investigation analyzed the pilot's braking technique and the aircraft's performance capabilities. While the aircraft was capable of stopping within the available distance, the investigation found that the pilot's application of the brakes—specifically releasing and reapplying them—reduced deceleration effectiveness. The investigation also noted that the presentation of performance data in the Airplane Flight Manual (AFM) was complex and potentially prone to error.
Findings
- The primary cause of the system indications was a pre-impact failure of the support bracket for the right main landing gear weight-on-wheels switch.
- The pilot's decision to initiate a go-around, while understandable, led to an inevitable runway overrun once the attempt to rotate failed.
- Braking effectiveness was reduced because the pilot did not apply maximum braking immediately after touchdown and intermittently released the brakes.
- The complexity of the performance charts in the AFM contributed to difficulties in managing the aircraft's landing requirements under failure conditions.