History of the Flight
The flight originated from Guernsey on 28 November 1998 as a performance-related test flight. The commander filed a flight plan indicating a transit to the Berry Head VOR at FL 100, followed by manoeuvres in the Plymouth area. After takeoff at 0918 hrs, the aircraft was handed to London Air Traffic Control Centre (LATCC) and later to Exeter ATC at 0943 hrs. The crew requested a block of airspace between FL 60 and FL 100 and was vectored north to avoid Plymouth departures. As the aircraft approached FL 60, the commander requested further descent to FL 50, which was approved. At 0947 hrs, Exeter ATC observed the transponder altitude readout indicating FL 47 and called the aircraft to confirm the local safe level of 3,500 feet. No reply was received; the transponder and primary radar return disappeared simultaneously. Repeated calls remained unanswered. Multiple eyewitnesses reported the aircraft in a left spin or spiral descent at high engine power, with no smoke or fire before impact. The ground impact was followed by a post-crash fire.
Aircraft Information
The aircraft, a DHC Dash 7-102 (registration VP-CDY), was manufactured in 1983. It originally operated in Norway until 1996, when it was acquired by an Egyptian operator. After about 18 months in Egypt, the operator faced financial difficulties, and the aircraft was repossessed by a leasing company. It was ferried to Guernsey for extensive maintenance to address gaps in documentation. The aircraft remained out of service for approximately one year before the test flight. The Cayman Islands Civil Aviation Authority issued a special flight authorization for private category flight testing. A previous test flight on 25 November 1998 revealed insufficient climb performance due to No. 3 engine issues; that engine was replaced, and the 28 November flight was planned to cover performance elements only. However, the aircraft lacked a valid UK exemption to operate in UK airspace.
Meteorological Conditions
At takeoff from Guernsey at 0900 hrs, conditions were surface wind 290°/17 kt, visibility 5,000 meters in rain, with scattered clouds at 300 feet and broken clouds at 700 and 1800 feet. Forecast for the Plymouth area indicated visibility 25 km and few clouds between 2,500 and 5,000 feet. An aftercast for 1000 hrs showed wind at 5,000 feet of 280°/25 kt and temperature -3°C. Eyewitnesses near the crash site described very clear, bright, and cool weather.
Pilot Experience and Training
The commander, aged 75, held a Canadian Airline Transport Pilot's Licence with Cayman Islands validation and approximately 15,000 total flying hours, including 4,000 on type. He had flown a Dash 7 last on 17 October 1998 but had recent Dash 8 production test flights. The first officer, aged 66, also held a Canadian ATPL with Cayman Islands validation and had 17,200 total hours (1,700 on type). His last Dash 7 flight was in June 1998, but he flew a Dash 8 production test flight on 23 November 1998 with the same commander. The two pilots had flown together frequently. During test flights, the commander occupied the right seat to direct the flight, record data, set power, and handle communications, while the first officer handled the controls from the left seat.
Accident Site and Wreckage
The aircraft crashed on the southern slopes of Dartmoor at approximately 500 feet amsl. Impact characteristics indicated a high descent rate, low forward speed, and rapid left rotation, with the aircraft in an erect, nose-down, left wing low attitude. A sustained ground fire largely destroyed the wreckage, preventing a full examination. However, it was determined that the airframe was structurally complete with all doors attached. The No. 1 propeller was feathered and not rotating at impact; the other three propellers were rotating under power. Flaps were fully retracted, and landing gear was up. Control cable continuity could not be fully confirmed due to fire damage. Analysis of caution light panels showed no evidence of bulb filament stretch, and several captions related to the shut-down engine were not illuminated as expected.
Probable Cause
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