What happened
On 9 September 2017, a Piper PA-28-140 Cherokee, registration G-BAKH, departed from Manchester City Airport for a private flight to Oban. The departure occurred following heavy rain, which had left the runway surface with patches of standing water. Prior to takeoff, the pilot performed an accelerate-stop maneuver to verify rotation speed on the wet surface.
During the takeoff roll, the pilot utilized a short-field technique involving two stages of flaps. While the aircraft became airborne, it failed to gain sufficient altitude or airspeed. The pilot was faced with an immediate hazard: overhead power lines located approximately 1,400 m beyond the runway end. To avoid these lines and the nearby M6-2 motorway, the pilot initiated a left turn, which necessitated a forced landing in a nearby potato field. The impact with the soft soil caused the landing gear to sink, resulting in a sudden stop that caused the pilot and one passenger to strike the instrument panel. The aircraft was destroyed, resulting in one serious and two minor injuries among the passengers, while the pilot sustained minor injuries.
The investigation
The AAIB examined the aircraft's weight, engine performance, and the runway conditions. Investigations revealed that the aircraft was significantly above its maximum takeoff weight (MTOW). The actual takeoff weight was calculated at 2,576 lb, exceeding the permitted 2,150 lb limit.
Engine inspections by an independent firm found no major mechanical failures, though a 5-8% reduction in power due to camshaft wear was estimated. Furthermore, the investigation compared the required takeoff distance against the available runway length. Due to the heavy load and wet conditions, the required distance was estimated at 3,912 ft, whereas the available runway distance was only 641 m.
Findings
- The aircraft was operating significantly above its maximum takeoff weight.
- The required takeoff distance was nearly double the available runway length.
- The use of a high nose attitude and additional flaps during takeoff created significant drag, hindering acceleration.
- While engine wear may have slightly reduced power, the extreme weight and insufficient runway length were the primary factors preventing a safe climb.