History of the Flight
The pilot, who held a Private Pilot's Licence with 1,572 hours total (1,210 on type), planned to refuel the helicopter before returning to his private operating site. After starting the engine, air traffic control cleared him to hover taxi from his parking spot on the grass northeast of the apron to the refuelling point, which he knew. The weather was good: surface wind from 270° at 7 knots and visibility over 10 km. The hover taxi was uneventful at a skid height of about 4 feet.
The refuelling area, located on the apron, comprises a small single-storey building and three fuel dispensing pumps with hoses. The pilot approached from the north, slowed to a hover, and maintained the 4-foot skid height. He yawed the helicopter 90° to the right to land parallel to the pumps, then moved a few feet left to ensure the refuelling hose would reach the fuel filler on the right side. As he commenced a descent to land, the main rotor blade tips struck the overhanging roof of the single-storey building. The pilot landed immediately and shut down the helicopter, isolating fuel and electrical systems before exiting through his side door.
The point of impact on the building was outside the pilot's forward field of view during landing.
Aerodrome Information
The aerodrome operator reported that a white line surrounds the refuelling area. Additionally, two short parallel white lines are painted adjacent to a drainage channel, opposite the fuel pump nearest the single-storey building (which has a longer hose), to provide position guidance for helicopters. This marking information does not appear in the United Kingdom Aeronautical Information Publication (UKAIP) or commercially available flight guides.
The UKAIP entry for Northampton/Sywell Aerodrome states: 'Ground Movement – a. No apron markings, caution when parking to ensure adequate wing tip clearance. Aircraft should not block access to the refuelling area and hangar access gate when parking on the concrete apron. b. All parking self-manoeuvring, assistance available on request.'
The flight guide that the pilot consulted states: 'No apron markings, all parking at pilot's discretion.'
Conclusion
The pilot stated that as he approached the fuel pumps, his eye line was level with the roof overhang and he had not appreciated the potential hazard. After turning parallel to the pumps, the building was located over his left shoulder, behind him, and out of his field of view. When he descended to land, he could not see the obstacle, and the main rotor blade tips struck the roof overhang. The pilot had consulted a commercially available flight guide but was unaware of the unpublished white markings at the refuelling area.