What happened
On March 17, 1977, a Boeing 707-436 was conducting the fourth day of a conversion base training program at Glasgow-Prestwick Airport. The crew consisted of a commander, a trainee first officer acting as the pilot, a captain under training serving as flight engineer, and a supervisory first officer.
Prior to departure, the commander briefed the trainee on managing crosswind takeoff techniques, noting a forecast wind of 190 degrees at 18 knots with gusts up to 35 knots. The aircraft, weighing 94,580 kg, was cleared to taxi to runway 13 and subsequently entered the active runway from a fast turnoff. Shortly after 08:48, the aircraft began its takeoff run from a rolling start.
During the rotation to a pitch of 4.5 degrees, the commander performed a simulated failure of the number one engine by reducing thrust on that engine and notifying the crew. While the aircraft initially climbed to an altitude of roughly 20 to 30 feet, the left wing suddenly dropped by approximately 20 degrees, causing the number one engine nacelle to strike the runway edge. This triggered a significant yaw and roll toward the right.
The aircraft continued to sink until the number four nacelle also impacted the ground. The plane tracked sideways down the runway, resulting in the collapse of the landing gear and the separation of the engines and structural components. The aircraft came to rest approximately 2,230 metres from the start of the takeoff roll near the intersection of runway 03/21. A fire broke out upon impact; while external flames were managed quickly, an internal fire persisted for about 50 minutes. There were 0 fatalities reported in this incident.
Findings
The accident was caused by a delay in applying necessary corrective actions during the execution of a simulated outboard engine failure maneuver.