Accident Overview
On a local post-maintenance test flight, the aircraft departed Glasgow Airport at 1422 LT with two pilots and two engineers aboard. The crew, consisting of pilot Walter Duward, copilot Stan Kemp, and engineers Paddy Quinn and Jimmy Moore, flew north at an altitude of 4,000 feet under VFR mode. After approximately seven and a half minutes, the captain requested clearance to return to the Glasgow Control Zone. Less than two minutes later, while cruising in poor weather conditions including snow showers, the aircraft struck the slope of Mt Ben More, which rises to 3,852 feet. The impact caused the aircraft to disintegrate, and all four occupants were killed.
Weather and Altitude
The flight encountered marginal visual meteorological conditions with snow showers. The minimum sector altitude for the area was 4,400 feet, and BEA's minimum safe altitude was 5,000 feet, but the decision to fly at FL 40 (3,800 feet amsl) was permissible for a VFR flight. The aircraft's altitude of 4,000 feet was below the terrain elevation at the impact point.
Contributory Factors
Officially reported factors include: the crew's failure to maintain a safe altitude and insufficient attention to navigational procedures. Additionally, although the captain obtained some weather information during a visit to the meteorological office, he did not seek a briefing from the Duty Forecaster, which may have deprived him of information about strong winds at the proposed flight level. The decision to operate under VFR in prevailing weather was questionable but likely explicable given the nature of the test flight. Map reading over snow-covered terrain presented obvious difficulties, and temporary distractions from the flight engineering test program may have increased the possibility of error. The exact circumstances are not known, but the accident probably occurred in 'whiteout' conditions associated with a snow shower.