What happened
On the evening of May 4, 2006, a Piper PA 23 aircraft, registration F-OHSA, departed from Saint Pierre Pierrefonds airport in Réunion for a night VFR flight. After a brief stop at Saint Denis earlier in the day, the aircraft took off from runway 15 at approximately 16:08 UTC.
Shortly after takeoff, while attempting to turn right toward the 'pointe au sel' waypoint, the aircraft began to lose altitude. Witnesses on the ground, including an AFIS agent and airport firefighters, observed the aircraft bank sharply to the right and descend into the sea. The aircraft struck the water approximately 1,200 meters from the coast and disappeared. Despite extensive search efforts, including underwater surveys, neither the aircraft nor the four occupants were ever recovered.
The investigation
The investigation focused on the flight conditions and the aircraft's final maneuvers. Investigators examined the aircraft's maintenance records, which showed no anomalies, and confirmed the aircraft was within its weight and balance limits. The crew consisted of four experienced pilots, all qualified for night VFR operations.
Investigators analyzed the meteorological conditions, noting that while the night was dark and the moon was invisible, intermittent rain showers were occurring. The investigation also looked into the possibility of a technical failure or a loss of situational awareness. Debris, including wooden fragments from the airframe, seat covers, and a landing gear component, was recovered from the ocean. A piece of the engine control block was later found by a fisherman, showing settings that roughly corresponded to a climb configuration.
Findings
- The aircraft entered a period of total darkness with very few visual references after leaving the illuminated runway.
- The presence of rain showers may have created a 'halo effect' from the aircraft's lights, further obscuring the horizon.
- The aircraft performed a turn earlier than usual, which may have been an attempt to exit the rain and find better visibility.
- The primary cause of the accident was likely spatial disorientation of the crew, potentially exacerbated by a technical failure or a combination of both factors.