# NTSB DEN99LA037: Boeing 757-222, N586UA, Climax, CO, February 7, 1999

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Limited investigation · Final report
- Date: February 7, 1999, 08:27 local (15:27 UTC)
- Place: Climax, CO
- Location: 39.3689° N, 106.1836° W: Placed by OpenAirDocs: center of Climax, CO, within about 6 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=39.3689&lon=-106.1836&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Serious injuries
- Injuries: 1 serious, 28 uninjured
- Status: Completed, report October 13, 2000
- Report: Approved by Office Director
- NTSB case key (mKey): 45732
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN99LA037
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/45732/pdf
- Page: https://openairdocs.org/ntsb/DEN99LA037

## Probable cause

The flight's encounter with turbulence.

## Sequence of events

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

- In flight encounter with weather, cruise
  - weather condition - turbulence (cause)

## Analysis

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.

## Factual narrative

On February 7,1999, at 0827 mountain standard time, a Boeing 757-222, N586UA, was not damaged following an encounter with turbulence near Climax, Colorado.  The 2 airline transport pilots, 5 flight attendants, and 22 passengers were not injured; however, 1 flight attendant was seriously injured.  The airplane was being operated by United Air Lines, Inc., under Title 14 CFR Part 121.  Visual meteorological conditions prevailed for this scheduled domestic passenger flight which originated from Denver, Colorado, approximately 30 minutes before the accident.  An IFR flight plan had been filed with a destination of Santa Ana, California.

FAA records indicate that air traffic control cleared United Airlines flight 553 to an altitude of 35,000 feet via the Rockies Three Departure (DEN R-240).  At approximately 0820, the captain of flight 553 radioed ahead to another United flight on the same departure course and altitude, requesting weather status.  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.

United Airlines records indicate that the flight crew had been notified of a Significant Meteorological (SIGMET) report for moderate to occasionally severe turbulence between FL300 and FL420.  An FAA inspector with the Denver FSDO determined that United flight 553 was south of the SIGMET box at the time of the severe turbulence event.

## Aircraft

- Registration: N586UA (not matched to a registry record)
- Reported make and model: Boeing 757-222
- Category: Airplane
- Serial number: 26710
- Airframe hours: 19634
- Engines: P&W 2037M 37000 lbs thrust turbo fan
- Damage: No damage
- Flight: Part 121
- Registered owner: United Air Lines Inc.
- Airworthiness certificate: Standard, Transport
- Last inspection: Continuous airworthiness, March 6, 1998, 3,330 hours before
- Departed: DEN, DENVER, CO
- Destination: SNA, SANTA ANA, CA
- Flight plan: IFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 39; airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 9,000 total, 1,497 in this make and model, 3 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 160° at 8 knots
- Visibility: 10 statute miles
- Lowest ceiling: 25,000 ft broken
- Temperature: 36 °F, dew point 21 °F
- Altimeter: 29.00 inHg
- Observed at: DEN, 70 nm away

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 19990207014579A](https://openairdocs.org/incident/19990207014579A), Feb 7, 1999: Boeing 757222, Climax, CO. (.19)On February 7, 1999, at 0841 mountain standard time, a Boeing 757-222, N586UA, was not damaged following an encounter with clear air turbulence near…

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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