5 fatalities

1971-03-31: Boeing 720 (N3166) — Western Airlines — Ontario, United States of America

Ontario, United States of AmericaLanding (descent or approach)

On March 31, 1971, a Boeing 720 (registration N3166) operated by Western Airlines was involved in an aviation accident near Ontario, United States of America during landing or approach. 5 people were killed. Investigators recorded the probable cause as: The failure of the aircraft rudder hydraulic actuator support fitting. The failure of the fitting resulted in the inapparent loss of left rudder control which, under the conditions of the flight, precluded the pilots’ ability to maintain directional control… This summary draws on records from the Bureau of Aircraft Accidents Archives (B3A); 2 related events involving the same aircraft type or operator are linked below.

Sourcesthe Bureau of Aircraft Accidents Archives (B3A)Primary reportUpdated 1781235361Data APIEditorial standards

During a simulated engine-out missed approach to Ontario, the aircraft lost control and crashed, killing all five crew members. Investigation found failure of the rudder hydraulic actuator support fitting.

Overview

A training flight from Los Angeles to Ontario ended in a crash when the aircraft went out of control on final approach. The airplane was totally destroyed and all five crew members were killed.

Flight Details

The pilot under supervision was tasked with completing an instrument landing system (ILS) approach with one engine simulated inoperative. After the approach, a missed approach and go-around procedure was to be executed. The flight check captain was also on board to supervise the training exercise.

Accident Sequence

On final approach to runway 25R, the airplane went out of control and crashed in a field. The impact resulted in the complete destruction of the aircraft.

Probable Cause

The official investigation determined the probable cause to be the failure of the aircraft rudder hydraulic actuator support fitting. This failure resulted in the inapparent loss of left rudder control, which, under the conditions of the flight, precluded the pilots' ability to maintain directional control during a simulated engine-out missed approach. Additionally, the existing weather conditions degraded external visual cues, thereby hampering rapid assessment of aircraft performance by the flight check captain.