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Last updated: 27 September 2020
Status:Definitief
Datum:donderdag 31 mei 1984
Tijd:13:34
Type:Silhouette image of generic B722 model; specific model in this crash may look slightly different
Boeing 727-222
Luchtvaartmaatschappij:United Airlines
Registratie: N7640U
Constructienummer: 19913/672
Bouwjaar: 1968
Motoren: 3 Pratt & Whitney JT8D-7B
Bemanning:slachtoffers: 0 / inzittenden: 7
Passagiers:slachtoffers: 0 / inzittenden: 98
Totaal:slachtoffers: 0 / inzittenden: 105
Schade: Groot
Gevolgen: Repaired
Plaats:Denver-Stapleton International Airport, CO (DEN) (   Verenigde Staten)
Fase: Start (TOF)
Soort vlucht:Binnenlandse lijnvlucht
Vliegveld van vertrek:Denver-Stapleton International Airport, CO (DEN/KDEN), Verenigde Staten
Vliegveld van aankomst:Las Vegas-McCarran International Airport, NV (LAS/KLAS), Verenigde Staten
Vluchtnummer:UA663
Beschrijving:
Before takeoff, the crew of flight UA663 noted cumulus clouds and virga in the area. At 13:27, a de Havilland Canada DHC-7 crew reported a 25 kt loss of airspeed, but several other aircraft then took off without reporting a problem. Due to radio congestion, the captain did not query other aircrews, but decided to climb out at V2 plus 20. when the controller cleared US663 for takeoff, he advised the crew of numerous wind shears in 3 quadrants, but used incorrect terminology in issuing the wind shear alert. During takeoff, the aircraft struck an ILS localizer antenna, 1074 ft from the departure end of the runway, and damaged the lower fuselage. When unable to pressurize the aircraft, the crew returned to the airport and landed.
An investigation revealed the aircraft encountered wind shear from microburst activity which reached its greatest activity as US663 was taking off. The wind sheared from an 8 kt headwind to 40 to 56 kts over a 44 second period. The crew noted a hesitation while accelerating through 120 kts, then at or beyond Vr speed of approx. 141 kts, the aircraft momentarily lost 20 kts.

Probable Cause:

Probable Cause:
weather condition..windshear

Contributing Factors:
object..approach light/navaid
weather condition..rain
weather condition..high wind
weather condition..gusts
weather condition..unfavorable wind
radio communications..excessive
airport/facilities..inadequate
weather evaluation..inaccurate..pilot in command
information unclear..atc personnel(lcl/gnd/clnc)

Accident investigation:
cover
Investigating agency: NTSB
Status: Investigation completed
Accident number: DCA84AA025
Download report: Summary report

Bronnen:
» NTSB


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Kaart
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 Denver-Stapleton International Airport, CO en Las Vegas-McCarran International Airport, NV bedraagt 983 km (614 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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