On the fourth day of a conversion training program at Prestwick Airport, Scotland, a Boeing 707-436 was to be used on a training flight. On board the aircraft was a crew of four;
Commander - Left seat ( Pilot Monitoring)
Trainee First Officer - Right seat (Pilot Flying)
Trainee Captain - Acting Flight engineer
Supervisory First Officer - Observer seat
The aircraft at its final position at the start of recovery operations
(Source baaa-acro.com ©Bob Woolnough)
After all required checks were completed the four Rolls Royce Conway 508 engines were started. This was followed by a comprehensive briefing by the commander on cross-wind take-off techniques, based on the planned take-off runway (Runway 13) and the take-off with a cross-wind (190º at 18 knots, gusting 35 knots). Special emphasis was given to the need for in to the wind aileron and opposite rudder. The commander demonstrated the required amount of flight control inputs to the trainee.
Calculated speeds for the runway/weather/weight (94.580 kg) combination were computed as follows;
V1 -125 knots
VR - 125 knots
V2 - 142 knots
VMCG - 125 knots
VMCA - 119 knots
At 08:42 taxi clearance was received, and the aircraft started rolling towards the runway, during the taxi the "Taxying checklist" was completed.
The aircraft during recovery operations (Source baaa-acro.com ©Bob Woolnough)
After receiving ATC clearance the aircraft entered the active runway from a high-speed turn-off, leaving 2388 metres of runway, for a required 1433 metres. The rolling take-off commenced at 08.48 lt (local time), with the wind reported at 220º at 15 knots. Rightwing down aileron and left rudder was applied before full take-off power was set. The flight engineers called out the required speeds and at VR the aircraft was rotated to a 4,5º pitch attitude, at that time the commander pulled back the #1 thrust lever simulating a #1 engine failure, simultaneously calling out "number one engine's failed".
The aircraft initially climbed normally to a height of 20 - 30 feet, when suddenly the left wing dropped ~20º and the #1 engine struck the left edge of the runway. This was followed by a yaw and roll to the right while losing altitude. The #4 engine then struck the runway. This resulted in the aircraft sliding sideways down the runway, causing the engines to break away and the landing gear to collapse. The aircraft came to a stop approximately 2230 metres after entering the runway. A post-accident fire broke out, however all crew managed to evacuate the aircraft via the forward service door.
The Trainee Captain (Acting Flight Engineer) broke his foot in the evacuation, all crew were taken to the airport medical centre. It took firefighters 50 minutes to fully extinguish all flames.
The aircraft during recovery operations (Source baaa-acro.com ©Bob Woolnough)
The Accidents Investigation Branch of the Department of Trade investigated the accident. On the 5th of September 1978, they published their investigation report with the following cause as the conclusion of the investigation;
The accident was caused by a loss of control by the pilots which resulted from their delay in taking full corrective action during a simulated failure of the #1 engine during take-off.
A full overview of all Findings and Safety Recommendations can be found in the accident report which can be accessed by clicking on the .pdf file below;