DCA84AA025
1984-05-31 · DENVER, Colorado, United States · None · 1 aircraft · Status: Completed
Airport DEN
N7640U has since been reassigned. It is now registered to a different aircraft (CIRRUS DESIGN SR20, built 2025), which was not involved in this event.
Aircraft involved
Factual narrative
BEFORE TAKEOFF, THE CREW OF N7647U (UA FLT 663) NOTED CUMULUS CLOUDS & VIRGA IN THE AREA. AT 1327, A DEHAVILLAND DASH 7 CREW RPRTD A 25 KT LOSS OF AIRSPEED, BUT SVRL OTHER ACFT THEN TOOK OFF WITHOUT RPRTG A PROBLEM. DUE TO RADIO CONJESTION,THE CAPTAIN DID NOT QUERY OTHER AIRCREWS, BUT DECIDED TO CLIMB OUT AT V2 PLUS 20. WHEN THE CONTROLLER CLEARED FLT 663 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 ACFT STRUCK AN ILS LOCALIZER ANTENNA, 1074 FT FROM THE DEPT END OF THE RWY, & DAMAGED THE LOWER FUSELAGE. WHEN UNABLE TO PRESSURIZE THE ACFT, THE CREW RETURNED TO THE ARPT & LANDED. AN INVESTIGATIONREVEALED THE ACFT ENCOUNTERED WIND SHEAR FROM MICROBURST ACTIVITY WHICH REACHED ITS GREATEST ACTIVITY AS FLT 663 WAS TAKING OFF. THE WIND SHEARED FROM AN 8 KT HEADWIND TO 40 TO 56 KTS OVER A 44 SEC PERIOD. THE CREW NOTED A HESITATION WHILE ACCELERATING THRU 120 KTS, THEN AT OR BEYOND VR SPEED OF APRX 141 KTS, THE ACFT MOMENTARILY LOST 20 KTS. Source: NTSB Aviation Accident Database (Pre-2008 Archive) Retrieved: 2026-02-12
Verbatim from NTSB's published report. Source file
NTSB_1984_DCA84AA025.txt.
Findings + structured fields enriched from FAA avall.mdb.
Full investigation docket on
data.ntsb.gov ↗.
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Related research
Matched on aircraft type or causal vocabulary (wind shear, microburst). All research papers
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Attention is given to the detailed features of a servere microburst event, the flight behavior of a 727 airliner in such an event as predicted by a numerical simulation, and several low level wind she…
- NASA NTRS 2019 · Contractor Report (CR) An Examination of Aviation Accidents Associated with Turbulence, Wind Shear and Thunderstorm
The focal point of the study reported here was the definition and examination of turbulence, wind shear and thunderstorm in relation to aviation accidents.
- NASA NTRS 2019 · Conference Paper Analysis of aircraft control strategies for microburst encounter
Analyses have indicated that improved control strategies could reduce the threat posed by the presence of microburst-type wind shear during aircraft takeoffs and landings.
- NASA NTRS 2013 · Conference Paper Optimal nonlinear estimation for aircraft flight control in wind shear
The most recent results in an ongoing research effort at Princeton in the area of flight dynamics in wind shear are described.
- NASA NTRS 2013 · Conference Paper Air/ground wind shear information integration: Flight test results
An element of the NASA/FAA wind shear program is the integration of ground-based microburst information on the flight deck, to support airborne wind shear alerting and microburst avoidance.