What happened
On June 1, 2002, an HFL Stratos 300 micro light aeroplane, registration PH-1V7, was conducting a local flight at Stadskanaal airfield. The pilot, who was a student without a full license, had been performing several engine-off maneuvers to utilize thermal currents. After approximately 40 minutes of gliding, the pilot attempted to restart the engine at an altitude of 700 meters, but the engine failed to ignite. Following several unsuccessful attempts, the battery was depleted.
Unable to restart the engine, the pilot transitioned to a gliding approach. To manage altitude, the pilot performed 360-degree turns and executed a sideslip toward the airfield. During the final approach, the pilot's maneuvers caused the aircraft to overshoot the runway. In an attempt to correct the flight path, the pilot performed a steep right-hand turn, which resulted in the right wingtip striking bushes on a nearby dike. The aircraft subsequently spun and came to a rest against a container. The impact resulted in light injuries to the pilot, but the aircraft was unrecoverably damaged.
The investigation
The investigation focused on the engine starting failure and the subsequent landing sequence. It was established that the PH-1V7 lacked an alternator, meaning the battery was only charged while in the hangar. The investigation found that the pilot attempted to fly with a nearly depleted battery, which directly led to the engine failure. Additionally, the aircraft was an early model that was not equipped with air brakes, meaning altitude management relied entirely on aerodynamic maneuvers like slipping.
Findings
- The primary cause of the engine failure was the use of a nearly depleted battery for multiple engine restarts.
- The pilot's lack of experience in performing engine-off landings in this specific aircraft type contributed to the loss of control during the approach.
- The presence of thermal currents during the final approach complicated the pilot's ability to maintain a stable descent.
- The pilot's decision to conduct solo flight maneuvers without an instructor increased the operational risk, particularly given the limited flight hours on this type.