United Airlines Flight 1193
Boeing 737-522 · Incident during landing
From Billings Logan International Airport (BIL) to Denver International Airport (DEN)
Event
- NTSB case
- DEN07IA058
- 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
- Unknown
- 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
- Visual Meteorological Cond
Boeing 737-522
- 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
- N928UA
- Operator
- United Airlines
- Onboard fatalities
- Unknown
- Route
- From Billings Logan International Airport (BIL), Billings, MTTo 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
- Landing · landing roll
- 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
- Miscellaneous/other
- 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
- Driver of vehicle › Procedures/directives, not followed
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The snowplow driver had been plowing snow on an airport service road. When he finished, the driver departed for another area of the airport that needed plowing, which required crossing a taxiway and active runway. The driver stopped short of the taxiway, but without ATC or airport operations clearance, crossed the runway. The driver saw a landing airplane as he was crossing the runway and increased acceleration. The flight crew saw the snowplow holding short of the taxiway. They landed, but during the landing roll, they saw the snowplow cross in front of them. "Significant" reverse thrust and brakes were used to bring the aircraft to a halt on the runway. The ground controller did not see the snowplow, but was alerted to the runway incursion by the flight crew's report. The Airport Movement Area Safety System (AMASS) was operational, but no alarm sounded.
Probable cause
The snowplow driver's failure to follow procedures/directives by crossing an active runway without clearance, resulting in a runway incursion and near collision with an airplane during its landing roll.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record DEN07IA058
- Event ID
- 20070206X00142
- Case number
- DEN07IA058
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
Source notes (5)
- 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, coordinates, damage. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 2007-02-03.
- API snapshot SHA-256: 283548518644ebf371faef5d6eea268bde575c59b741dd5c9da9e14f8b477dde; retrieved 2026-09-18T14:47:24.440Z.
- The NTSB's operator name is blank for N928UA; the operator shown is the name the NTSB's other records give its FAA operator code, UALA.