What aircraft was involved and where did it happen?

The accident on 2001-05-23 involved a Cessna 421C, registration G-BHKJ, at RAF Lyneham, GB.

What was the probable cause of the accident?

The propeller struck a CO2 fire extinguisher left in front of the aircraft's nose wheel during an engine start performed without the presence of a starter crew.

Propeller damage during engine start at RAF Lyneham

A Cessna 421C sustained propeller damage during an engine start at RAF Lyneham after a CO2 fire extinguisher was left in the aircraft's path.

What happened

On 23 May 2001, a Cessna 421C, registration G-BHKJ, was prepared for a private flight at RAF Lyneham. Earlier that morning, the aircraft had arrived at the airfield, and the pilot had estimated an engine start time of 1230 hrs. In anticipation of the start, a crew from the RAF Visiting Aircraft Section (VAS) had placed a CO2 fire extinguisher in front of the aircraft's nose wheel.

At 1250 hrs, the pilot requested and received permission to start the engines. This process was completed without the presence of the VAS starter crew. After receiving taxi clearance, the pilot began to manoeuvre the aircraft forward and to the left. After moving approximately two metres, a loud bang occurred, and debris was seen flying from the starboard side of the aircraft. Nearby RAF personnel observed a metallic object landing near them and signaled for the aircraft to stop. There were no injuries to the two crew members or five passengers on board.

The investigation

An investigation involving the pilot's report and an RAF Flight Safety Investigation established that a propeller blade on the right engine had become damaged and was loose within the hub assembly. The investigation also found that the CO2 extinguisher, which had been left near the nose wheel, had been struck by the propeller, resulting in a slice through its applicator assembly. Fragments from the broken extinguisher were discovered near other aircraft parked in the vicinity.

Findings

The engine start was conducted without the supervision of the VAS starter crew.
The propeller struck a CO2 fire extinguisher that had been left in the aircraft's path.
The pilot did not specifically request that his estimated start time be communicated to the VAS or Station Operations.

Safety action

Following the investigation, the RAF recommended that the RAF Lyneham VAS provide visiting aircrew with clear guidance on contacting Station Operations and the VAS. It was further recommended that engine starts should not proceed without a VAS member present and that ATC requests should clearly state the pilot's exact requirements. Additionally, it was advised that ground servicing and support equipment should not be left outside the designated painted areas next to parking bays.