Introduction
On 30 March 2008 at 1336 hours UTC, a Cessna Citation 500, registration VP-BGE, crashed approximately 2 nautical miles north-northeast of Biggin Hill Airport. The aircraft was operated as a private flight to Pau, France. None of the two flight crew and three passengers survived.
Accident Sequence
Shortly after takeoff from Biggin Hill, the flight crew reported engine vibration and initiated a return to the departure airfield. During the downwind leg for Runway 21, the aircraft descended. The flight crew reported a major power problem just before the aircraft struck the side of a house, resulting in an intense fire.
Findings
The investigation, conducted by the UK Air Accidents Investigation Branch (AAIB), found that:
- Both the pilot and co-pilot were properly licensed and qualified for single-pilot operation.
- The aircraft was certified, equipped, and maintained in accordance with regulations.
- A missing rivet head on the left engine fuel shut-off lever may have led to an inadvertent shutdown of that engine.
- Approximately 70 seconds prior to impact, neither engine was producing any thrust.
- Both engines were operating when the aircraft struck the house, and both were relit prior to impact but with insufficient time to prevent ground impact.
- The rudder trim was in the full nose-right position.
- The air cycle machine bearing distress was identified as the most probable cause of the vibration described by the pilots as "ENGINE VIBRATION."
- The accident was not survivable.
The aircraft had no flight data recorder or cockpit voice recorder installed, which limited critical information for the investigation.
Contributory Factors
The AAIB identified the following contributory factors:
1. The air cycle machine caused the vibration that led to the crew attempting to return to the departure airfield. 2. A missing rivet head on the left engine fuel shut-off lever may have led to an inadvertent shutdown of that engine. 3. Approximately 70 seconds prior to impact, neither engine was producing any thrust. 4. A relight attempt on the second engine was probably started before the relit first engine had reached idle speed, resulting in insufficient time for enough thrust to be developed to arrest the aircraft's rate of descent before ground impact.
Safety Recommendations
The AAIB issued three safety recommendations:
- Safety Recommendation 2010-014: That the Federal Aviation Administration require Cessna Aircraft Inc to introduce a scheduled inspection of the Cessna Citation 1 throttle quadrant assembly to ensure the integrity of the riveted joints securing the fuel shut-off levers to the throttle levers.
- Safety Recommendation 2010-015: That the Federal Aviation Administration require Cessna Aircraft Inc to amend the 'EMERGENCY RESTART – TWO ENGINE' checklist to emphasise the significance of only restarting one engine at a time.
- Safety Recommendation 2010-016: That the International Civil Aviation Organisation adopt the proposals of its Flight Recorder Panel for the requirement to install flight recorders on turbine-engine powered aeroplanes of a maximum certified takeoff mass of 5,700 kg or less.