What happened
On 5 May 2018, a Morane Saulnier MS.315E D2, registration G-BZNK, was conducting a return flight from Bodmin to Branscombe. While flying at approximately 1,200 ft near the coast, the engine lost power. The pilot, observing that the inland terrain was covered in hedges and wires, identified a south-facing beach at Sidmouth as a suitable landing site.
Upon approaching the western end of the beach, the pilot maneuvered to avoid bystanders near the water's edge. The aircraft landed on a surface of sand and pebbles. There were no injuries to the pilot or the passenger, and the aircraft sustained no reported damage. Following the landing, the crew and bystanders assisted in moving the aircraft above the high tide mark.
The investigation
An inspection of the aircraft revealed that the fuel tank contained only about two litres of fuel remaining at the time of the incident. Investigators examined the Rotec R3000 engine's fuel pressure regulator, which uses a primer button to allow fuel flow during starting.
A Light Aircraft Association inspector discovered that a return spring in the priming system had become disconnected. This failure caused the cockpit priming lever to leave the primer button in a depressed state. Furthermore, black soot was found on the landing gear struts behind the exhaust pipes, a sign of incomplete combustion caused by an over-rich fuel mixture.
Findings
- The engine lost power because the available fuel was exhausted much faster than the pilot's calculations predicted.
- A disconnected return spring caused the fuel primer to remain continuously active.
- The continuous operation of the primer significantly increased the engine's fuel consumption rate.
- The pilot's prior training in forced landing procedures and familiarity with the aircraft's gliding characteristics contributed to the successful landing.
Safety action
- The LAA intends to recommend that priming installations of this design be modified so that the fuel pressure regulator returns to normal operation even if the priming mechanism fails.