United Airlines Boeing 737-322 incident
Boeing 737-322 · Incident: loss of control on ground/water during takeoff
From an unrecorded airport to Denver International Airport (DEN)
Event
- NTSB case
- CHI91IA062
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Incident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 0 · all aircraft and ground
- Ground fatalities
- 0
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- Airline
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Instrument Meteorological Cond
Boeing 737-322
- Aircraft type
- Boeing 737
- Category
- Airplane
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N396UA
- Operator
- United Airlines
- Onboard fatalities
- Unknown
- Route
- From not recordedTo Denver International Airport (DEN), Denver, CO
- Aircraft age
- Not recorded
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 121: Air Carrier
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- Takeoff · roll/run
- First occurrenceThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Loss of control on ground/water
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- None
Cause areas
- Copilot/second pilot › Directional control, not maintained
- Copilot/second pilot › Throttle/power control, improper use of
Approximate · Estimated position: the centre of Kansas City, MO, the place the record names. Not the accident site.
NTSB narrative
THE FIRST OFFICER HAD CONTROL OF THE AIRCRAFT FOR TAKEOFF ON ICE COVERED RUNWAY. AFTER THE THROTTLES WERE ADVANCED FOR TAKEOFF, THE AIRCRAFT ROLLED STRAIGHT AHEAD FOR APPROXIMATELY 2 SECONDS, THEN BEGAN TO SLIDE TO THE LEFT. THE CAPTAIN TOOK CONTROL OF THE AIRCRAFT BUT COULD NOT MAINTAIN DIRECTIONAL CONTROL, OR STOP THE AIRCRAFT. THE AIRCRAFT DEPARTED THE LEFT SIDE OF THE RUNWAY AND CAME TO A STOP IN THE MUD AND SNOW. AN EMERGENCY EVACUATION WAS CONDUCTED. INVESTIGATION REVEALED THAT ON APPLICATION OF POWER FOR TAKEOFF, THE RIGHT ENGINE HAD A 10% GREATER N1 THAN THE LEFT ENGINE. THE FIRST OFFICER WAS ON HIS INITIAL OPERATING EXPERIENCE IN THE AIRCRAFT.
Probable cause
IMPROPER USE OF THE THROTTLES, AND FAILURE TO MAINTAIN DIRECTIONAL CONTROL BY THE FIRST OFFICER. FACTORS RELATED TO THE INCIDENT ARE: ICE ON THE RUNWAY, LACK OF TOTAL EXPERIENCE IN THE TYPE AIRCRAFT AND OPERATION BY THE FIRST OFFICER, AND INADEQUATE SUPERVISION BY THE CAPTAIN.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CHI91IA062
- Event ID
- 20001212X16273
- Case number
- CHI91IA062
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: local date, investigation status, damage. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 1991-01-08.
- API snapshot SHA-256: 234221d434cdb2e8d8d3fc471d28c95c971531919448d64bb6c95bb406afb886; retrieved 2026-09-18T18:57:29.418Z.