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Last updated: 18 July 2018
Statuts:Enquête Officielle
Date:mercredi 19 juillet 1989
Type/Sous-type:Silhouette image of generic DC10 model; specific model in this crash may look slightly different
McDonnell Douglas DC-10-10
Compagnie:United Airlines
Immatriculation: N1819U
Numéro de série: 46618/118
Année de Fabrication: 1973
Heures de vol:43401
Moteurs: 3 General Electric CF6-6D
Equipage:victimes: 1 / à bord: 11
Passagers:victimes: 110 / à bord: 285
Total:victimes: 111 / à bord: 296
Dégats de l'appareil: Détruit
Conséquences: Written off (damaged beyond repair)
Lieu de l'accident:Sioux Gateway Airport, IA (SUX) (   Etats-Unis d'Amérique)
Élévation des lieux de l'accident: 335 m (1099 feet) amsl
Phase de vol: A l'atterrissage (LDG)
Nature:Transport de Passagers Nat.
Aéroport de départ:Denver-Stapleton International Airport, CO (DEN/KDEN), Etats-Unis d'Amérique
Aéroport de destination:Chicago-O'Hare International Airport, IL (ORD/KORD), Etats-Unis d'Amérique
Numéro de vol:UA232
United Flight 232 departed Denver at 14:09 CDT for a flight to Philadelphia. Cruising altitude was FL370. About 1 hour and 7 minutes after takeoff the crew heard a loud bang, followed by vibration and a shuddering of the airframe; the no. 2 engine had suffered an uncontained failure. It then appeared that the hydraulic pressure was zero. The DC-10 didn't respond anymore to flight control inputs and the descending right turn was arrested by using no. 1 engine power reduction. The air driven generator (ADG), which powers the no. 1 auxiliary hydraulic pump, was deployed but hydraulic power couldn't be restored. An emergency was declared at 15:20, and vectors to Sioux City were given by Minneapolis ARTCC. An off-duty training check airman was travelling on Flight 232 and offered his assistance. He was asked to manipulate the throttles to control pitch and roll, which was difficult because the plane had a continuous tendency to turn to the right The no. 1 and 3 thrust levers couldn't be used symmetrically, so he used two hands to manipulate the throttles. Sioux City Airport was sighted at 9 miles out, but the aircraft was aligned with the closed runway 22 (6600 feet long) instead of the longer (8999 feet) runway 31. Given the position and the difficulty in making left turns, the approach to runway 22 was continued. The aircraft approached with a high sink rate (1620 feet/min for the last 20 seconds) at an airspeed of 215 knots. At about 100 feet above the ground the nose began to pitch downward and the right wing dropped. The plane touched down on the threshold slightly left of the centreline, skidded to the right and rolled inverted. The DC-10 caught fire and cartwheeled.

Probable Cause:

PROBABLE CAUSE: "The National Transportation Safety Board determines that the probable cause of this accident was the inadequate consideration given to human factors limitations in the inspection and quality control procedures used by United Airlines' engine overhaul facility which resulted in the failure to detect a fatigue crack originating from a previously undetected metallurgical defect located in a critical area of the stage 1 fan disk that was manufactured by General Electric Aircraft Engines. The subsequent catastrophic disintegration of the disk resulted in the liberation of debris in a pattern of distribution and with energy levels that exceeded the level of protection provided by design features of the hydraulic systems that operate the DC-10's flight controls."

Accident investigation:
Investigating agency: NTSB
Status: Investigation completed
Duration: 1 year and 4 months
Accident number: NTSB/AAR-90-06
Download report: Final report

» Aviation Week & Space Technology 24.7.89 (96,97), 31.7.89(30-31)
» NTSB/AAR-90/06

Opérations de secours

NTSB issued 25 Safety Recommendations

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Ce plan montre l'aéroport de départ ainsi que la supposée destination du vol. La ligne fixe reliant les deux aéroports n'est pas le plan de vol exact.
La distance entre Denver-Stapleton International Airport, CO et Chicago-O'Hare International Airport, IL est de 1436 km (897 miles).
Accident location: Exact; deduced from official accident report.

Les informations ci-dessus ne représentent pas l'opinion de la 'Flight Safety Foundation' ou de 'Aviation Safety Network' sur les causes de l'accident. Ces informations prélimimaires sont basées sur les faits tel qu'ils sont connus à ce jour.
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