What happened
On 5 October 1999, a Europa aircraft, registration G-FLOX, was performing a private flight at Redhill Aerodrome in Surrey. Following a takeoff, the pilot executed a touch-and-go maneuver on Runway 08R. During the subsequent climb, at an altitude of approximately 150 feet, the pilot experienced intense engine vibrations. This prompted the pilot to perform a forced landing within the airfield boundaries. There were no fatalities and no injuries to the two occupants on board.
The investigation
Investigators examined the aircraft and the propeller, which was a modified two-bladed wooden model. This specific propeller had been reworked by the manufacturer to optimize performance for the Jabiru 2200A engine by adding layers of fiberglass to alter the blade pitch. The investigation found that a section of the fiberglass skin, consisting of four layers from the front surface of one blade, had separated in flight. This detached material was recovered approximately 500 meters from the aircraft's final position.
Analysis of the propeller revealed several areas of poor construction. Near the hub, insufficient pressure during the curing process resulted in inadequate wetting of the glass fibers. Along the trailing edge, the bond between the resin and the wood was also found to be poor. Most significantly, a smooth, unbonded area was identified near the leading edge, situated just behind the polyurethane erosion protection insert.
Findings
- The primary cause of the vibration and subsequent forced landing was the detachment of the fiberglass skin from the propeller blade.
- The separation likely originated near the leading edge, where the fiberglass skin was vulnerable to disbonding due to flexural and impact loads.
- The use of black paint on the propeller may have contributed to the failure, as solar heating could cause thermal expansion stresses or soften the resin.
- The specific propeller involved was a trial unit and did not represent the standard production manufacturing process.