What happened
On 3 September 2006, a Beagle B121 Series 1 Pup, registration G-AZSW, was participating in the Royal Aero Club’s ‘Schneider Trophy Air Race’. While flying at approximately 600 ft over the sea near Sandown Beach, the pilot attempted to rejoin the landing circuit for Bembridge Airfield. During the maneuver, the pilot selected the fuel pump and switched fuel tanks. Following these actions, the engine began to lose power progressively.
In an attempt to rectify the issue, the pilot applied carburettor heat and enriched the mixture while pitching up and reducing throttle to slow the aircraft. When power was not restored, the pilot opted to abandon restart attempts. Because breakwaters on Sandown Beach prevented a landing on land, the pilot executed a precautionary ditching in the shallow water just offshore. The aircraft initially floated before drifting toward the shore. The pilot, who was wearing a full harness, exited the aircraft through the left door without injury.
The investigation
The AAIB investigation examined the engine and fuel systems, as well as local meteorological conditions. The pilot noted that the right fuel tank had been selected, which contained approximately 60 kg of fuel. A maintenance inspection of the aircraft did not identify any mechanical defects or obvious causes for the engine failure.
Findings
- The engine experienced a progressive loss of power following the selection of the right fuel tank and the activation of the fuel pump.
- Atmospheric conditions at the time included a temperature of 18.8ºC and a dew point of 18ºC, resulting in a relative humidity of 95%.
- Carburettor icing is considered the most likely cause of the power loss, as the high humidity and specific power settings were highly conducive to ice formation.
- The aircraft sustained damage to the propeller, engine cowling, and nose landing gear due to the impact and subsequent immersion in salt water.