What happened
On 12 August 2007, a Nomad N2/2B, registration N6302W, was conducting an aerial work flight to drop 13 parachutists near Chatteris Airfield, Cambridgeshire. During the climb through approximately 8,500 ft, the aircraft entered a large cumulonimbus cloud. While attempting to navigate the weather, the pilot failed to activate the engine anti-ice system in time, leading to a loss of power in the left engine due to icing.
After unsuccessful attempts to restart the engine, the pilot decided to return to the departure airfield for a single-engine landing. To compensate for the reduced power, the pilot increased the approach speed from 70 kt to 80 kt. The aircraft landed further down the runway than intended. Due to the combination of the high approach speed, a damp grass surface, and insufficient reverse thrust, the aircraft overran the end of the runway. During the overrun, the nosewheel struck a ditch, resulting in the collapse of the nose landing gear.
The investigation
The AAIB investigation examined the pilot's qualifications and the sequence of the engine failure. It was established that the pilot was operating under the privileges of a CAA licence but held an FAA licence that allowed him to fly US-registered aircraft without a specific type rating. Under UK (CAA/JAR) regulations, a specific type rating for the Nomad was required, which the pilot did not possess.
Investigators also reviewed the weather conditions, noting that the area was experiencing unstable air and heavy showers. The investigation confirmed that the engine failure was a direct result of encountering ice before the anti-ice system could be engaged. Furthermore, the investigation looked into the complexities of international licensing harmonization between the FAA and other aviation authorities.
Findings
- The engine failure was caused by the encounter with ice prior to the activation of the engine anti-ice system.
- The aircraft overran the runway because of a high approach speed combined with a damp grass surface and reduced reverse thrust.
- The pilot's approach speed was increased to 80 kt to maintain a safe margin during a single-engine operation.
- The pilot did not hold the required type rating for the aircraft under CAA/JAR standards.
- There were no injuries to the crew or the 13 passengers on board.