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Last updated: 20 April 2021
Datum:maandag 27 augustus 1990
Type:Silhouette image of generic B744 model; specific model in this crash may look slightly different
Boeing 747-422
Luchtvaartmaatschappij:United Airlines
Registratie: N174UA
Constructienummer: 24381/762
Bouwjaar: 1990-01-05 (8 months)
Aantal vlieguren:2952
Aantal vluchten:402
Motoren: 4 Pratt & Whitney PW4056
Bemanning:slachtoffers: 0 / inzittenden: 20
Passagiers:slachtoffers: 0 / inzittenden: 323
Totaal:slachtoffers: 0 / inzittenden: 343
Schade: Licht
Gevolgen: Repaired
Plaats:Los Angeles International Airport, CA (LAX) (   Verenigde Staten)
Fase: Landing (LDG)
Soort vlucht:Internationale lijnvlucht
Vliegveld van vertrek:Sydney-Kingsford Smith International Airport, NSW (SYD/YSSY), AustraliŽ
Vliegveld van aankomst:Los Angeles International Airport, CA (LAX/KLAX), Verenigde Staten
The crew noted that the nose and main body gear indicated up and locked after normal gear extension. The crew used the alternate gear extension procedure, which was unsuccessful. The aircraft landed on runway 25R with the nose and main body gear retracted when the flight reached the minimum fuel state. Examination of the aircraft revealed that the selector valve for the affected gear was in the up and locked position, and the bolt which connects the valve arm to the cockpit control cable system was missing. The bolt for the wing gear selector valve arm was found partially backed out; the nut and cotter pin were missing. The aircraft was delivered to United in January of 1990 and had 2,952 flight hours and 402 cycles. Detailed review of the maintenance records proved that United had not performed any maintenance on the landing gear system. A second alternate gear extension procedure involving de-energizing the hydraulic system for the affected gear is not published in the crew manuals, taught during initial training, nor available on any checklist.

Probable Cause:

PROBABLE CAUSE: "The failure of the manufacturer to ensure that the landing gear selector valves and their associated drum link assemblies were properly installed prior to delivery of the aircraft. A factor in the accident was the lack of information available to the crew concerning the secondary alternate gear extension procedure."

Accident investigation:
Investigating agency: NTSB
Status: Investigation completed
Duration: 2 years and 4 months
Accident number: LAX90IA305
Download report: Summary report

» Aviation Week & Space Technology 3.9.90 (p.205)


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Deze kaart geeft het vliegveld van vetrek weer en de geplande bestemming van de vlucht. De lijn tussen de vliegvelden geeft niet de exacte vliegroute weer.
De afstand tussen Sydney-Kingsford Smith International Airport, NSW en Los Angeles International Airport, CA bedraagt 12026 km (7516 miles).

This information is not presented as the Flight Safety Foundation or the Aviation Safety Networkís 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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