Aircraft Accident/Incident Report

Climax, Colorado 80429
Sunday, February 7, 1999 8:27 MST

NTSB Narrative Summary Released at Completion of Accident

After departing from Denver, Colorado, United Airlines flight 553 was cleared to climb to FL350 via the Rockies Three Departure (DEN R-240). The captain radioed ahead to another United flight on the same departure course and altitude, requesting a weather report. The other United flight reported 'occasional light chop uh mostly smooth.' The captain released the flight attendants to move about the cabin. The captain reported that between FL340 and FL345, the flight encountered severe turbulence. One flight attendant received a fractured knee cap and a concussion.

NTSB Probable Cause Narrative

The flight's encounter with turbulence.

Event Information

Type of Event Accident
Event Date 2/7/1999
Event Day of the Week Sunday
Time of Event 827
Event Time Zone Mountain Standard Time
Event City CLIMAX
Event State COLORADO
Event Country --
Zipcode of the event site 80429
Event Date Year 1999
Event Date Month 2
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude
Event Location Longitude
Event Location Airport
Event Location Nearest Airport ID
Indicates whether the acc/inc occurred off or on an airport Off Airport/Airstrip
Distance from airport in statute miles --
Degrees magnetic from airport --
Airport Elevation --
Weather Briefing Completeness Full
Investigator's weather source Weather Observation Facility
Time of the weather observation 753 Mountain Standard Time
Direction of event from weather observation facility (degrees) 60
Weather Observation Facility ID DEN
Elevation of weather observation facility 5431
Distance of event from weather observation facility (units?) 70
Time Zone of the weather observation MST
Lighting Conditions Day
Lowest Ceiling Height 25000
Lowest Non-Ceiling Height 7000
Sky/Lowest/Cloud Conditions Scattered
Sky Condition for Lowest Ceiling Broken
Visibility Runway Visual Range (Feet) 0
Visibility Runway Visual Value (Statute Miles) 0
Visibility (Statute Miles) 10
Air Temperature at event time (in degrees celsius) 2
Dew Point at event time (in degress fahrenheit) -6
Wind Direction (degrees magnetic) 160
Variable Wind Indicator Unknown
Wind Speed (knots) 8
Wind Velocity Indicator Unknown
Wind Gust Indicator Unknown
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) 29
Density Altitude (feet) --
Intensity of Precipitation Unknown
METAR weather report --
Event Highest Injury Serious
On Ground, Fatal Injuries 0
On Ground, Minor Injuries 0
On Ground, Serious Injuries 0
Injury Total Fatal --
Injury Total Minor --
Injury Total None 28
Injury Total Serious 1
Injury Total All 1
Investigating Agency NTSB
NTSB Docket Number (internal use) 396
NTSB Notification Source --
NTSB Notification Date Feb 8 1999 12:00AM
NTSB Notification Time 1303
Fiche Number and/or location -used to find docket information IMAGE
Date of most recent change to record Dec 12 2000 11:20AM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N586UA
NTSB Number DEN99LA037
Missing Aircraft Indicator N
Federal Aviation Reg. Part Part 121: Air Carrier
Type of Flight Plan filed IFR
Flight plan Was Activated? --
Damage None
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name Boeing
Aircraft Model 757-222
Aircraft Series Identifier 757-222
Aircraft Serial Number 26710
Certified Max Gross Weight 260000
Aircraft Category Airplane
Aircraft Registration Class U.S. Registered/U.S. Soil
Aircraft is a homebuilt? No
Flight Crew Seats --
Cabin Crew Seats --
Passenger Seats --
Total number of seats on the aircraft 214
Number of Engines 2
Fixed gear or retractable gear Retractable
Aircraft, Type of Last Inspection Continuous Airworthiness
Date of Last Inspection Mar 6 1998 12:00AM
Airframe hours since last inspection 3330
Airframe Hours 19634
ELT Installed Unknown
ELT Activated Unknown
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name UNITED AIR LINES INC.
Aircraft Owner Street Address 1200 ALGONGUIN
Aircraft Owner City ELK GROVE TOWNS
Aircraft Owner State IL
Aircraft Owner Country
Aircraft Owner Zipcode 60007
Operator is an individual? --
Operator Name
Operator Same as Owner? Yes
Operator Is Doing Business As --
Operator Address Same as Owner? Yes
Operator Street Address
Operator City
Operator State
Operator Country
Operator Zip code
Operator Code UALA
Owner has at least one certificate Yes - certificate holder
Other Operator of large aircraft? No
Certified for Part 133 or 137 Operation Unknown
Operator Certificate Number --
Indicates whether an air carrier operation was scheduled or not Scheduled
Indicates Domestic or International Flight Domestic
Operator carrying Pax/Cargo/Mail Passenger Only
Type of Flying (Per_Bus / Primary) Unknown
Second Pilot on Board No
Departure Point Same as Event No
Departure Airport Code DEN
Departure City DENVER
Departure State CO
Departure Country
Departure Time 759
Departure Time Zone MST
Destination Same as Local Flt --
Destination Airport Code SNA
Destination City SANTA ANA
Destination State CA
Destination Country
Specific Phase of Flight Cruise
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Jan 2 2001 10:34AM
User who most recently changed record dbo
Since inspection or accident --
Event Location Runway Number and Location 0
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --