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Fecha:lunes 31 marzo 1975
Tipo:Silhouette image of generic B732 model; specific model in this crash may look slightly different
Boeing 737-247
Operador:Western Air Lines
Registración: N4527W
Numéro de série: 20131/165
Año de Construcción: 1969-05-07 (5 years 11 months)
Horas Totales de la Célula:14076
Motores: 2 Pratt & Whitney JT8D-9A
Tripulación:Fatalidades: 0 / Ocupantes: 6
Pasajeros:Fatalidades: 0 / Ocupantes: 93
Total:Fatalidades: 0 / Ocupantes: 99
Daños en la Aeronave: Anulado
Consecuencias: Written off (damaged beyond repair)
Ubicación:Casper Airport, WY (CPR) (   Estados Unidos de América)
Fase: Aterrizaje (LDG)
Naturaleza:Vuelo Doméstico Programado
Aeropuerto de Salida:Denver-Stapleton International Airport, CO (DEN/KDEN), Estados Unidos de América
Aeropuerto de Llegada:Casper Airport, WY (CPR/KCPR), Estados Unidos de América
Número de Vuelo: 470
Western Air Lines flight 470 to Casper and Minneapolis departed Denver at 07:03 in the morning. The airplane, on an IFR flightplan, climbed to its cruising altitude of FL220. At 07:36, following a descent to 12,000 feet, the flightcrew contacted Casper approach control and advised that the flight was about 12 miles south of the Evansville Intersection. At that time, the controller cleared the flight to use the localizer back course approach for runway 25, to circle to runway 3, or to land straight in. The weather reported to the crew indicated poor visibility with light snow falling and wind 040deg at 9 knots. One minute later, the approach controller advised that "runway 7/25 has been
plowed. There's about a 1/4-inch of powder snow on it. Braking action reported, Convair 580, as poor. Runway 3/21 is being plowed at this time."
At 07:51, Flight 470 reported at the Henning Intersection and was cleared to contact the Casper Tower. The tower controller cleared the flight to land on runway 25 and gave the wind as 030deg at 8 knots. The flight was also advised by the controller that a disabled snow blower was "just west of the intersection runway 21, left side runway 25, on the edge ...." At 07:41:42, the first officer called out "thousand to go to the field." At 07:42:09, the first officer called "approaching minimums," and 12 seconds later, he called "just about at minimums."
The aircraft then flew level for a few moments a t the minimum descent altitude (MDA). At 07:42:25,
the first officer called the runway in sight directly below the aircraft. At that time airspeed was 150 knots and the flaps were at 25deg. The first office then set the flaps at 30deg as the captain initiated the final descent. The aircraft crossed the threshold at reference speed +15 knots. The aircraft touched down 2375 feet from the departure end of the runway, about 6,306 feet from the approach end of the runway. The aircraft went off the departure end of the runway to the right of the centerline. After striking several metal stanchions in the first row of terminal bar lights, which were located 200 feet off the end of the runway, the aircraft struck a shallow irrigation ditch 280 feet off the runway end. The aircraft veered farther to the right and stopped about 800 feet beyond the departure end of the runway.

Probable Cause:

PROBABLE CAUSE: "The failure of the pilot-in-command to exercise good judgment when he failed to execute a missed approach and continued a non-precision approach to a landing without adequately assessing the aircraft's position relative to the runway threshold. Contributing tot the accident were the excessive height and speed at which he crossed the approach end of the runway and the failure of other flight crew members to provide him with required callouts."

Accident investigation:
Investigating agency: NTSB
Status: Investigation completed
Duration: 213 days (7 months)
Accident number: NTSB/AAR-75-15
Download report: Final report
Language: English

» ICAO Circular 146-AN/96 (60-76)

Subsiguiente / acciones de seguridad

NTSB issued 1 Safety Recommendation

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photo of Boeing-737-247-N4527W
accident date: 31-03-1975
type: Boeing 737-247
registration: N4527W

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 Denver-Stapleton International Airport, CO to Casper Airport, WY as the crow flies is 370 km (231 miles).

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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Global Action Plan for the Prevention of Runway Excursions (GAPPRE): recommendations and guidance material to prevent runway excursions
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