What happened
On 5 August 2007, a Piper PA-28-140 Cherokee, registration G-AVRP, departed from Runway 23 at Sandown Airport for a private flight to France. The aircraft was carrying one pilot and three passengers. During the takeoff roll, the aircraft's performance was insufficient, resulting in a long ground run. After lifting off, the aircraft climbed to approximately 50 feet but failed to gain sufficient altitude to clear rising ground beyond the runway end.
As the aircraft approached a wooded area, it was observed to pitch up and clear the uppermost branches of the trees by a small margin. However, the nose then dropped, and the aircraft descended behind the tree line. The aircraft subsequently struck another line of trees and crashed into a field, where it caught fire. All 4 fatalities occurred as a result of the impact and the subsequent intense fire.
The investigation
The investigation focused on the aircraft's performance and the state of the engine. Examination of the Lycoming O-320 engine revealed significant wear on the camshaft. Specifically, a cam lobe responsible for operating the inlet valves of cylinders 1 and 2 had been worn down by approximately 0.138 inches. This wear reduced the valve-lifting profile, which decreased the volume of the fuel/air mixture during the induction stroke, thereby reducing engine power.
Testing conducted by the AAIB confirmed that such wear could result in a loss of approximately 10 bhp, or roughly 6.7% of the engine's rated maximum power. The investigation also examined the airfield environment, noting that a recent survey had identified trees that had grown to penetrate the takeoff climb surface. The investigation also looked into the aircraft's weight and takeoff conditions, noting the aircraft was likely operating near its maximum allowable takeoff weight.
Findings
- The engine suffered from significant camshaft lobe wear, which caused a measurable reduction in maximum power output.
- The aircraft was likely operating at a weight close to its maximum authorized limit, which, combined with reduced power, compromised climb performance.
- Trees had grown into the takeoff climb surface, creating an obstacle that the aircraft could not safely clear given its degraded performance.
- The takeoff ground roll exceeded the required distance, indicating the aircraft was underperforming even before liftoff.