Root cause of the accident was deemed to be poor visibility. With low cloud and freezing fog, the pilot was simply unable to see the top of building under construction or the crane. Flying regulations stipulate a 500ft clearance above buildings. At the point of impact, the helicopter was approximately 105ft from the building.
The helicopter was flying to the east of London Heliport at 0820 hrs on 16 January 2013 when it struck the jib of a crane, attached to a building development at St George Wharf, at a height of approximately 700ft. The pilot, who was the sole occupant of the helicopter, and a pedestrian were fatally injured when the helicopter impacted a building and adjacent roadway. The report says that the pilot "was subject to operational and commercial pressures". He had ealier told a colleague that he was going to cancel the flight but subsequently changed his mind.
The building at St George Wharf was not included in the helicopter’s obstacle databases. However, the crane at St George Wharf had been notified correctly through the NOTAM (Notice to Airmen) system and the building was added to the Digital Vertical Obstruction File (DVOF) and notified to Aeronautical Information Service (AIS). However, accident investigators found that the building was added to the DVOF “by coincidence rather than as the result of a systematic process of notification of en route obstacles”, so there are lessons to be learned there.
There is no effective system in place to anticipate the potential effects of new obstacles on existing airspace arrangements when the obstacles are outside safeguarded areas, the report by the Air Accidents Investigation Branch states (AAIB).
The report reveals that in 2009, the heliport operator raised concerns with the Civil Aviation Authority (CAA) that the then-proposed development at St George Wharf raised a conflict between standard operating altitudes on helicopter route H4 and a pilot’s obligation to adhere to Rule 5. This does not appear to have led to further discussion or action.
Rule 5 states: “Except with the written permission of the CAA, an aircraft shall not be flown closer than 500 feet to any person, vessel, vehicle or structure.”
The full report is available on the AAIB website.