1959-07-22: Boeing KC-97 Stratotanker (52-2703) — United States Air Force - USAF (since 1947) — Andover, United States of America

7 fatalitiesAndover, United States of AmericaFlight

A military refueling training mission ended in a fatal crash 1.3 miles south of Andover when an aircraft entered a dive and disintegrated upon impact.

What happened

During a nighttime aerial refueling training exercise departing from Pease AFB, New Hampshire, a military aircraft experienced a sudden loss of control. While operating at an altitude of 15,000 feet, the plane banked to the left and entered a steep dive. The aircraft subsequently struck a field located approximately 1.3 miles south of Andover.

The impact was severe enough to cause the aircraft to disintegrate. There were no survivors among the seven crew members on board during the accident.

Findings

An investigation conducted by the Air Force Accident Investigation Board identified a mechanical failure as the primary driver of the accident. The inquiry concluded that the loss of lubrication to the bearings in the #4 engine turbo supercharger led to the failure of the turbo supercharger shaft.

Following this failure, the turbine accelerated to a point of destruction. This event triggered an uncontained catastrophic fire, likely resulting from severed fuel lines or punctured fuel tanks within the wing structure.

Probable cause

A failure of the #4 engine turbo supercharger shaft caused by inadequate bearing lubrication led to a catastrophic engine fire.