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Last updated: 21 September 2021
Fecha:domingo 5 septiembre 1954
Tipo:Silhouette image of generic CONI model; specific model in this crash may look slightly different
Lockheed L-1049C-55-81 Super Constellation
Operador:KLM Royal Dutch Airlines
Registración: PH-LKY
Numéro de série: 4509
Año de Construcción: 1953
Horas Totales de la Célula:2498
Motores: 4 Wright R-3350 (972TC18DA1)
Tripulación:Fatalidades: 3 / Ocupantes: 10
Pasajeros:Fatalidades: 25 / Ocupantes: 46
Total:Fatalidades: 28 / Ocupantes: 56
Daños en la Aeronave: Anulado
Consecuencias: Written off (damaged beyond repair)
Ubicación:2,5 km (1.6 milles) SE de la costa de Shannon Airport (SNN) (   Irlanda)
Fase: Ascenso Inicial (ICL)
Naturaleza:Vuelo Internacional Programado
Aeropuerto de Salida:Shannon Airport (SNN/EINN), Irlanda
Aeropuerto de Llegada:New York-Idlewild International Airport, NY (IDL/KIDL), Estados Unidos de América
Número de Vuelo:KL633
The KLM Super Constellation, named "Triton", operated on the Amsterdam-New York route. A scheduled refueling stop was made at Shannon. The flight left Shannon Terminal Building at 02:30 hours at night and taxied to runway 14 (5643 feet long). The before takeoff run-up was completed in takeoff position.
Takeoff was made at 02:38. V1 speed was reached at 3500 feet and lift-off at 125 knots was made just over the V2 speed at approximately 4000 feet from threshold. The flight then passed over the remaining 1600 feet of runway in a shallow climb, retracting its landing gear. The Constellation entered a shallow descent over the River Shannon. The duration of the flight was about 31 seconds from the time it passed over the end of the runway until the aircraft first contacted the water in a tail-down slightly right-wing low attitude. It came to rest on the Middle Ground, a shallow mudbank 8170 feet from the end of the runway, after losing engines no. 3 and 4.

Probable Cause:

PROBABLE CAUSE: "1) Failure of the captain to correlate and interpret his instrument indications properly during flap retraction, resulting in necessary action not being taken in sufficient time. This failure was partially accounted for by the effect on instrument indications of inadvertent and unexpected gear re-extension. 2) Loss of aircraft performance due to inadvertent landing gear re-extension. 3) The captain failed to maintain sufficient climb to give him an opportunity of meeting unexpected occurrences."

» ICAO Accident Digest Circular 50-AN/45 (20-33)
» Nederlandse Constallations / H.Dekker


photo of Lockheed-L-1049C-Super-Constellation-PH-LKY
accident date: 05-09-1954
type: Lockheed L-1049C Super Constellation
registration: PH-LKY
photo of Lockheed-L-1049C-Super-Constellation-
Flight path of KLM Flt 633 after takeoff from Shannon - 5 SEP 1954

Video, social media

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 Shannon Airport to New York-Idlewild International Airport, NY as the crow flies is 4910 km (3069 miles).
Accident location: Exact; deduced from official accident report.

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Lockheed L-1049

  • 564 built
  • 5th loss
  • 2nd accidente fatal
  • The worst accident (a la hora)
  • 13th worst accident (actualmente)
» safety profile

  • 2nd worst accident (a la hora)
  • 5th worst accident (actualmente)
» safety profile