Incident
On 22 October 2002 at 1730 UTC, a Sikorsky S76A (Modified), registration G-BMAL, was making a short positioning flight between rigs in the southern North Sea. It was almost dark and intermittent rain showers were affecting the area. The helicopter was operated under a Public Transport (Passenger) flight, with two crew and no passengers. The commander, aged 45, held an Airline Transport Pilots Licence (Helicopters) and had 9,962 hours total flying experience, including 7,346 hours on type.
Approach and Landing
The pilots' forward windscreen was clear, but the chin windows were partly misted. The wind direction, reported as 190°/24 kt, required the approach to be flown by the co-pilot from the left seat. The co-pilot aimed for the centre of the marked circle on the helideck, per Company Standard Operating Procedures. The captain lost sight of the landing area in the last 100 feet of the descent but was content the approach was within normal parameters. Touchdown was uneventful, but after landing, the Helideck Landing Officer reported that the Automatic Deployable Emergency Locator Transmitter (ADELT), fitted to the rear fuselage, was damaged.
Damage and Crew Actions
The captain inspected the ADELT and found a fracture to the neck of the ADELT housing. The crew had been unaware of any contact with the rig during the approach, but witnesses later reported seeing the ADELT strike the helideck edge during landing; this information was not relayed to the crew. The captain and co-pilot decided to fly empty back to their base at North Denes for inspection by engineering personnel.
Investigation
The company conducted a thorough investigation and concluded the ADELT struck the deck-edge safety netting and then the seaward side of the cable tray during landing. Inspection found a dent in the cable tray, which surrounds the deck and protrudes about 5 inches above the helideck surface. The investigation determined that the helicopter had crossed the helideck below the safe profile either due to a too shallow approach with a small flare, or a normal sight picture approach with too hard a flare. A contributory factor may have been the helicopter's centre of gravity, which was 80% towards the aft limit and would have required a higher than normal nose attitude in the flare.
Recommendations
The investigation recommended that in future, the non-handling pilot should bring attitudes of 10° nose-up or more to the attention of the handling pilot when the helicopter is within 30 feet of the surface. Other recommendations included a review of the aiming point for the approach (other aircraft in the operator's fleet aim at the far side of the landing circle) and an investigation into possible solutions for the chin window misting problem. Finally, the investigation recommended that consideration be given to fitting an approved modification to reposition the ADELT from its present position under the tail to the right side of the fuselage, aft of the baggage bay.