- Date
- May 31, 1984, 13:34 local (19:34 UTC)
- Place
- Denver, CO
- Injuries
- 105 uninjured
- Damage
- Substantial damage
- Phase of flight
- Initial climb
- Aircraft
- N7640UBoeing 727-222
- Weather
- Visual (VMC) · Day
- Status
- Completed · report August 30, 1994
- Report
- Approved by Office Director
- NTSB office
- Major Investigations Division
- Safety recommendations
- Yes
- Case key
- 15809
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.
On this page
Sequence of events
NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.
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
- Reported as
- Boeing 727-222
- Category
- Airplane
- Serial number
- 19913
- Engine
- P&W JT8D-7B, 14,000 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
Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.
Flight crew
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 46
- Certificates
- 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