- Accident Flight
As shown in figure 3, GPS data for the accident flight (which lasted about 7 min) showed that the helicopter departed the frozen pond about 2313. It climbed to about 700 ft msl (about 250 ft above ground level [agl]) and accelerated to about 60 knots. The helicopter flew southwest and then southeast, circumnavigating a 1,000-ft msl hill at altitudes of 700-800 ft msl (about 150-200 ft agl, depending on terrain elevation), and then it slowed to about 20 knots as it approached the Intertie. About 2315, the helicopter turned right and headed south along the Intertie for about 30 seconds at altitudes of about 900-1,100 ft msl (about 200-300 ft agl) and a speed of 60 knots. Before the helicopter reached an area where the Intertie crossed over another 1,000-foot msl hill (which was one of several in a cluster of low-lying hills directly ahead of the helicopter’s flightpath), the helicopter turned right and deviated toward a slight gap in the hills at a speed of 70 knots.