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Accident
Last updated: 17 October 2017
Status:Schlussbericht
Datum:Montag 2 April 1956
Zeit:08:10
Flugzeugtyp:Boeing 377 Stratocruiser 10-30
Fluggesellschaft:Northwest Orient Airlines
Kennzeichen: N74608
Werknummer: 15954/50
Baujahr: 1949-10-10 (6 years 6 months)
Betriebsstunden:18489
Triebwerk: 4 Pratt & Whitney R-4360-B6
Besatzung:Todesopfer: 1 / Insassen: 6
Fluggäste:Todesopfer: 4 / Insassen: 32
Gesamt:Todesopfer: 5 / Insassen: 38
Sachschaden: Zerstört
Konsequenzen: Written off (damaged beyond repair)
Unfallort:8,7 km (5.4 Meilen) SW vom Land entfernt von Seattle/Tacoma International Airport, WA (SEA) (   USA)
Flugphase: Während des Fluges (ENR)
Betriebsart:Inländischer planmäßiger Passagierflug
Flug von:Seattle/Tacoma International Airport, WA (SEA/KSEA), USA
Flug nach:Portland International Airport, OR (PDX/KPDX), USA
Flugnummer: 2
Unfallbericht:
Northwest Flight 2 (Seattle-Portland-Chicago-New York) took off from Seattle at 08:06. As the aircraft reached 2000 feet, at 145 knots airspeed, the flaps were retracted. Severe buffeting started and the aircraft tended to roll to the left. Thinking it was an asymmetric flap condition, the captain reduced power to stop the buffeting, but of no avail. Full power was applied again and plans were made to divert to McChord AFB. The plane continued to lose altitude and was not able to reach McChord. A ditching was carried out in Puget Sound. The aircraft sank 15 minutes after the ditching. It appeared that the aircraft had taken off with the engine cowl flaps fully open. Though not emphasized as a contributory factor, it must be noted that the cowl flap control on the Boeing 377 and Lockheed L-1049 move in opposite directions for the closing of the cowls. Most of the flight engineers flying time had been on L-1049 and DC-6 aircraft.

Probable Cause:

PROBABLE CAUSE: "The incorrect analysis of control difficulty which occurred on retraction of the wing flaps as a result of the flight engineer's failure to close the engine cowl flaps - the analysis having been made under conditions of great urgency and within an extremely short period of time available for decision."

Informationsquelle:
» ICAO Accident Digest No.8, Circular 54-AN/49 (72-75)


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photo of Boeing 377 Stratocruiser 10-30 N74608
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Map
This map shows the airport of departure and the intended destination of the flight. The line between the airports does not display the exact flight path.
Distance from Seattle/Tacoma International Airport, WA to Portland International Airport, OR as the crow flies is 207 km (129 miles).
Accident location: Approximate; accuracy within a few kilometers.

This information is not presented as the Flight Safety Foundation or the Aviation Safety Network’s opinion as to the cause of the accident. It is preliminary and is based on the facts as they are known at this time.
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Boeing 377

  • 56 built
  • 5th loss
  • 5th Fataler Unfall
  • 3rd worst accident (Zu diesem Zeitpunkt)
  • 4th worst accident (Momentan)
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