History of the Flight
The intended flight was from Elmsett to Blackpool for a business meeting. The pilot, accompanied by one passenger, inspected the aircraft before flight and found no defects. The pre-flight inspection included operation of the fuel drains for the main, auxiliary and tip fuel tanks to check for water. In the PA-30 Twin Commanche, the fuel drains are located in the fuel selector valves, accessible through an access panel behind the fuel tank selector levers. The pilot relied on a visual check of the transparent tubes attached to the selector valve filter bowls.
The pilot started the engines with the main tanks selected and changed to the auxiliary tanks as he set the radios and taxied to the threshold of Runway 23. He switched back to the main tanks for engine power checks, which were within normal limits. After contacting Wattisham for permission to take off into their MATZ, he began the take-off run. Acceleration was normal and the aircraft became airborne at 80 kt. The pilot held the aircraft level to accelerate to 100 kt before climbing. At that point, he noticed a slight yaw to the right and found the right-hand engine producing only about 2,000 RPM. Unable to land ahead, he continued the take-off, but the aircraft failed to accelerate beyond 80 kt. He climbed to avoid rising ground and trees and selected the landing gear UP. During gear transit, the aircraft yawed severely to the right. The pilot lowered the nose to regain directional control. Unsure whether the right engine had failed or suffered further reduction, and with throttle closure not reducing the yaw, he assumed engine failure and initiated the failed engine procedure. He turned left to avoid a house, but lost height. After the turn, the right wing tip struck the ground, causing the aircraft to slew and travel backwards into a hedge. The pilot and passenger were not seriously injured, unbuckled their harnesses, and left the aircraft. There was no fire. The pilot confirmed he feathered the right-hand propeller, possibly shortly before impact.
Aircraft Examination
Inspection after the accident revealed water in the fuel control unit of the right-hand engine. The aircraft had been refuelled at Gloucestershire Airport two days prior, with heavy rain in between. An experienced ground engineer noted previous problems with water ingress into PA-30 Twin Commanche fuel systems, but no ready explanation for this specific occurrence.
Fuel Drain Procedures
The manufacturer's Information Manual for the PA-30 Twin Commanche includes pre-flight inspection procedures for draining fuel valves and lines. It specifies separate procedures: one for before each flight and an expanded procedure when water may have entered tanks. Both require collecting drained fuel in a container to examine for water contamination. For the expanded procedure, drains should be opened for 10 to 12 seconds for each main and auxiliary cell. For normal pre-flight, the instructions specify draining for "a few seconds" per cell.