During the periods of flight captured on the video recording, the helicopter did not fly above 500 ft agl, and it was considerably lower for most of the time. Other aspects of the pilot’s handling of the aircraft were noteworthy: these included instances of very low flying, valley flying and other manoeuvres, as described below.
On the outbound flight the helicopter flew as low as 155 ft over open farmland, as indicated by the altimeter and, at one point, it flew over farm buildings at a height estimated from the video to be 275 ft. The pilot then rolled the helicopter rapidly into a brief but steeply banked right turn, before reversing the turn to the left, at which point a true indicated height of 335 ft was recorded.
When the helicopter departed from the farm on the accident fight, the pilot flew a ‘zoom’ climb, before descending into a narrow, steep-sided valley, next to the town of Larkhall. The valley is about 250 ft deep, and densely packed with trees along its length. This section of the recording showed the helicopter flying over trees at the valley’s edge at speed, with a separation from the trees estimated from the video footage at between 20 ft and 30 ft. It then pitched nose-down and descended into the valley, coming into similar proximity to trees on each side and below.
What could possibly go wrong?