2006 Piper PA-23 Aztec accident at Saint Pierre Pierrefonds (F-OHSA)

Accident overview and flight details On 4 May 2006, a Piper PA-23 Aztec, registration F-OHSA, operated by Aéroclub Roland Garros, crashed into the sea off Saint Pierre Pierrefonds in Réunion. The aircraft was on a night visual flight rules (VFR) navigation flight. It had departed Saint Denis de la Réunion at 15:07 UTC and landed at Saint Pierre Pierrefonds at 15:37 UTC. After a short stop, it took off from runway 15 at 16:08 UTC. During a right turn toward the departure point PW “pointe au sel,” the aircraft lost altitude, struck the sea surface, and disappeared. ## Aircraft, occupants, and damage The PA-23 Aztec was a twin-engine, low-wing monoplane with retractable tricycle landing gear and six seats. It was powered by two 250-horsepower Lycoming IO-540 C4B5 engines. The aircraft was first placed in service in 1968 and had serial number 27-3862. Its certificate of airworthiness was valid until 12 May 2008. Maintenance records showed no anomaly. The estimated takeoff mass was about 2,160 kg, within the maximum authorized mass of 2,355 kg and within mass and centering limits. Four men were aboard, all pilots qualified for night VFR and long-time friends who often flew together. Their medical certificates showed no problem. It was not possible to determine who was piloting the aircraft at the time of the accident. The occupants’ flight logs were not recovered. Their experience was determined from records kept by the aeroclub where they usually flew. Their multi-engine experience could not be determined. The aircraft sank and was not recovered. In the days after the accident, debris was found floating a few kilometers offshore, including wood pieces from the fuselage, two seat covers, two life jackets in their packaging, a torn life raft, and the left main landing-gear leg. There were no other damages. ## Weather, navigation, and communications Weather conditions were southeast trade-wind conditions. Clouds formed on the island’s slopes spread over coastal areas, while other clouds in the southeast flow caused light precipitation east of Saint Pierre. Around 19:00 UTC, a land breeze established. The sea was agitated with a strong southeast swell. At Saint Pierre Pierrefonds, the 15:00 UTC METAR reported wind 130° at 10 kt, visibility 9999, broken cloud at 3,300 ft, temperature 23°C, and QNH 1016. The automatic station at Pierrefonds recorded at 16:00 UTC wind 100° at 10 kt with gusts from 130° at 23 kt, no rain, overcast conditions, and a temperature of 23°C. Ground witnesses said the night was dark and the moon was invisible; this was confirmed by the first rescue helicopter crew on scene. Departure from Saint Pierre Pierrefonds on runway 15 was made by a right turn toward the departure point PW “la pointe au sel.” In night VFR, there were few light references after takeoff. The first visual light references were St Louis and the Etang salé, both on the route to PW. During takeoff, the crew was in contact with the AFIS agent at Saint Pierre-Pierrefonds. Because of a malfunction in the ground radio-communication recording system, the communications could not be preserved. ## Investigation findings and probable cause The investigation established that the aircraft struck the sea during a right turn after takeoff and sank. The analysis considered spatial disorientation as a phenomenon in the accident scenario. The probable cause of the accident was not explicitly stated in the provided source excerpt.