Status:	Schlussbericht
Datum:	31 MRZ 1971
Zeit:	06:33 PST
Flugzeugtyp:	Boeing 720-047B
Fluggesellschaft:	Western Air Lines
Kennzeichen:	N3166
Werknummer:	19439/621
Baujahr:	1966
Betriebsstunden:	11521
Anzahl Zyklen der Zelle:	7011
Triebwerk:	4 Pratt & Whitney JT3D-3B
Besatzung:	Todesopfer: 5 / Insassen: 5
Fluggäste:	Todesopfer: 0 / Insassen: 0
Gesamt:	Todesopfer: 5 / Insassen: 5
Sachschaden:	Zerstört
Konsequenzen:	Written off (damaged beyond repair)
Unfallort:	Ontario International Airport, CA (ONT) (USA)
Flugphase:	Annäherung (APR)
Betriebsart:	Ausbildungsflug
Flug von:	Los Angeles International Airport, CA (LAX/KLAX), USA
Flug nach:	Ontario International Airport, CA (ONT/KONT), USA
Flugnummer:	366

Unfallbericht:
Control was lost during a 3-engine missed ILS approach procedure and the aircraft crashed.
Failure of the aircraft rudder hydraulic actuator support fitting led to the loss of left rudder control. The loss of control situation was worsened by the degraded external visual clues (600 feet overcast; 1200m visibility in fog haze and smoke).

PROBABLE CAUSE: "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 during a simulated engine-out missed-approach. The existing weather conditions degraded external visual cues, thereby hampering rapid assessment of aircraft performance by the flight check captain."

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