1971-12-09: Beechcraft 80 Queen Air (N252Q) — Monarch Tile Company — Oklahoma City-Will Rogers, United States of America

7 fatalitiesOklahoma City-Will Rogers, United States of AmericaTakeoff (climb)

An aircraft crashed shortly after takeoff from Oklahoma City following a left engine failure during the initial climb phase.

What happened

During the initial climb following departure from Oklahoma City-Will Rogers Airport, the aircraft experienced a mechanical failure in its left engine. In an attempt to manage the emergency, the pilot feathered the left propeller and began a turn to the left. During this maneuver, the crew lost control of the aircraft. The plane subsequently entered a nose-down attitude and impacted the ground, resulting in a large explosion. There were seven fatalities among the occupants.

Findings

Investigations into the accident revealed that the failure of engine number five was caused by the breakage of a connecting rod cap. Several contributing factors were identified regarding the mechanical state and operation of the aircraft:

  • The engine components suffered from fatigue fractures and under-torqued hardware.
  • There were significant deficiencies in the maintenance and inspection procedures performed by ground personnel.
  • The aircraft was overloaded, exceeding its maximum gross weight by approximately 550 lbs.
  • The aircraft was improperly loaded for flight.
  • The pilot failed to maintain the necessary flying speed during the emergency.
  • The decision to turn toward the non-functioning engine contributed to the loss of control.

Probable cause

The failure of a connecting rod cap in the left engine due to fatigue and improper maintenance, compounded by an overweight aircraft configuration.