What happened
On 16 December 2011, a Piper PA-23-160, registration N100MC, was performing a private flight in the local area near South Cave, Humberside. While descending from 2,500 ft to land at Mount Airey Airfield, the pilot configured the aircraft by extending the flaps and landing gear. During the approach, the pilot noticed low cloud between the aircraft and the airfield and decided to redirect the approach to Runway 25.
As the aircraft was approximately one nautical mile from the runway threshold, the left engine lost power. The pilot attempted to maintain directional control using full right rudder, but the aircraft became difficult to handle due to the drag from the unfeathered, windmilling left propeller. Faced with electrical pylons ahead and the difficulty of performing a single-engine go-around at a low altitude, the pilot elected to perform a forced landing in a nearby field.
During the landing, the pilot flared slightly too high, causing the aircraft to stall at approximately six feet. The subsequent heavy impact caused the nose landing gear to detach and the left main gear to collapse. There were no injuries to the pilot or the passenger.
The investigation
The investigation examined the wreckage and the fuel used prior to the flight. It was noted that the aircraft had been refuelled with approximately 60 litres of unleaded MOGAS. While the pilot had strained the fuel through a filter to remove water, investigators found that the fuel in the left engine's carburettor fuel inlet pipe lacked the blue tinge characteristic of AVGAS 100LL.
Investigators also examined the engine's operational state. Both engines were found to be turning freely, and the spark plugs on the left engine were within an expected colour range. The damage to the airframe, including the left wing, flaps, and nose section, was consistent with a heavy landing.
Findings
- The left engine lost power during the approach to land.
- The pilot's ability to maintain straight and level flight was compromised by the drag produced by the windmilling left propeller, which had not been feathered.
- The decision to perform a forced landing was driven by the presence of electrical pylons and the low altitude, which made a single-engine go-around unsafe.
- The aircraft stalled during the landing phase due to a high flare, leading to the collapse of the landing gear and extensive structural damage.