History of the Flight
The pilot, who held a Private Pilot’s Licence with 416 hours total (84 on type), had flown earlier that day with an instructor to satisfy currency requirements. During that flight, he practiced maneuvers including simulated engine failures. He then refueled at Blackbushe Airport and departed at 1110 hrs for a private landing site near Lee-on-Solent, Hampshire, where he met his passenger. He departed again at 1525 hrs, intending to fly along the coast, but gliding activity at Lee-on-Solent prompted him to head south towards the Isle of Wight. Approaching Cowes from the north, he turned right to return to the landing site. After completing the turn, a loud bang was heard from above and behind; the helicopter lurched and controls became slack. Power to the rotors was lost. The pilot entered an autorotation; the airspeed indicator read zero. He and his passenger loosened their seatbelts and opened doors. The pilot aimed to land near boats for rescue. He made a controlled touchdown beside the Prince Consort Buoy. The helicopter filled with water and sank quickly. Both occupants vacated without injury and were rescued almost immediately.
Additional Information
The pilot reported that during start-up at Blackbushe, the main rotor took longer than usual to start turning. On the flight to the private landing site, the clutch caution light illuminated several times for less than six seconds each. At shutdown, the clutch light took longer than usual to extinguish. During the accident flight, the pilot thought he heard whining sounds but considered it might be imagination due to trepidation about overwater flight. Fuel records showed 40 litres of AVGAS uplifted at 0857 hrs and 55 litres at 1103 hrs. The pilot estimated 14 US gallons remaining before the accident flight, which lasted less than 20 minutes, leaving at least 10 US gallons. The weather included a south-westerly wind of 15 to 20 kt, broken cloud at 3,000 ft, visibility over 5,000 m, and temperature +18°C with dew point +11°C, indicating a possibility of moderate carburettor icing at cruise power.
Survival Aspects
Neither occupant wore a life jacket, and none were carried. The pilot’s decision to unlatch doors before touchdown was prudent, as distortion might have made opening difficult after a violent touchdown. The cabin flooded immediately, equalizing pressure and allowing door opening shortly after touchdown. The emergency procedures in the Pilot’s Operating Handbook (POH) under "Ditching – Power On" include door unlatching, but not under "Ditching – Power Off". A safety recommendation (2006-04) was made for the FAA to ensure Robinson Helicopter includes door unlatching instructions in all ditching procedures in the R22 POH.
Technical Investigation
No wreckage was recovered. A side-scan sonar survey of the seabed four days later found nothing, and the survey was terminated. Tidal movement was assessed at about 1 kt westward, potentially moving any wreckage at least 6 nm downstream. The symptoms reported by the pilot were consistent with failure of one of the two drive belts transmitting power from the engine to the main transmission. The AAIB noted known problems with low-time belts, particularly stretching after installation, which can cause belts to ride up out of pulley grooves during clutch engagement. G-CBPT had a matched pair of new belts fitted about 20 hours prior, and a clutch rigging and belt alignment check was carried out 6 hours earlier.