# NTSB DCA84AA025: Boeing 727-222, N7640U, Denver, CO, May 31, 1984

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Final report
- Date: May 31, 1984, 13:34 local (19:34 UTC)
- Place: Denver, CO
- Coordinates: 39.76094, -104.919433 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=39.7609&lon=-104.9194&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 105 uninjured
- Status: Completed, report August 30, 1994
- Report: Approved by Office Director
- NTSB office: Major Investigations Division
- Safety recommendations: Yes
- NTSB case key (mKey): 15809
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DCA84AA025
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/15809/pdf
- Board report AAR8501 (PDF): https://www.ntsb.gov/investigations/AccidentReports/Reports/AAR8501.pdf
- Page: https://openairdocs.org/ntsb/DCA84AA025

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- In flight encounter with weather, takeoff - initial climb
  - weather condition - rain (contributing factor)
  - weather condition - high wind (contributing factor)
  - weather condition - gusts (contributing factor)
  - weather condition - unfavorable wind (contributing factor)
  - safety advisory - issued, pilot of other aircraft
  - radio communications - excessive (contributing factor)
  - airport/facilities - inadequate (contributing factor)
  - weather evaluation - inaccurate, pilot in command (contributing factor)
  - information unclear, atc personnel(lcl/gnd/clnc) (contributing factor)
  - weather condition - windshear (cause)
- In flight collision with object, takeoff - initial climb
  - object - approach light/navaid (contributing factor)

## Analysis

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.

## Aircraft

- Registration: [N7640U](https://openairdocs.org/deregistered/N7640U-2007-03-14), registration cancelled 2007-03-14, S/N 19913, built 1969 (OpenAirDocs)
- Reported make and model: BOEING 727-222
- Registry model: [Boeing 727-222](https://openairdocs.org/model/boeing-727-222) (registry code 1384073) (OpenAirDocs)
- Registry engine: [Pratt & Whitney JT9D series](https://openairdocs.org/engine/pratt-whitney-jt9d-series) (registry code 52054, turbo-fan) (OpenAirDocs)
- Category: Airplane
- Serial number: 19913
- Engines: P&W JT8D-7B 14000 lbs thrust turbo fan
- Damage: Substantial damage
- Flight: Part 121
- Registered owner: United Airlines
- Airworthiness certificate: Standard, Transport
- Destination: LAS, LAS VEGAS, NV
- Flight plan: IFR
- Airport: DEN, Stapleton, runway 35L, 11,500 × 150 ft, concrete

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 46; airline transport, commercial; airplane ratings: multi-engine land; instrument ratings: airplane; medical: valid medical--no waivers/lim.; seat: left; flight hours: 12,400 total, 8,000 in this make and model, 69 in the last 30 days, 6 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Visibility: 20 statute miles
- Lowest ceiling: 8,000 ft broken
- Temperature: 82 °F, dew point 39 °F
- Altimeter: 29.00 inHg
- Observed at: DEN

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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