United Airlines Boeing B777-200B incident
Boeing B777-200B · Incident: on ground/water collision with object while standing
From Denver International Airport (DEN) to Chicago O'Hare International Airport (ORD)
Event
- NTSB case
- DEN06IA034
- 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
- Instrument Meteorological Cond
Boeing B777-200B
- Aircraft type
- Boeing 777
- 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
- N798UA
- Operator
- United Airlines
- Onboard fatalities
- Unknown
- Route
- From Denver International Airport (DEN), Denver, COTo Chicago O'Hare International Airport (ORD), Chicago, IL
- 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
- Standing · engine(s) operating
- 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
- On ground/water collision with object
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Minor
Cause areas
- Driver of vehicle › Clearance, not maintained
- Ground personnel › Clearance, not verified
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The airplane was parked at the remote deicing pad and type 4 deicing fluid was being applied to the right rear quadrant and the right wing of the airplane using a deicing truck with a boom. The truck's boom was raised at the time. The driver maneuvered the vehicle too close to the right wing trailing edge at the aileron resulting in the mid-section of the boom coming in contact with the wing. The boom operator cleared the wing for movement when she was not actually clear. The airplane and truck sustained minor damage. An operational inspection of the truck revealed no anomalies. The routine aviation weather report reported visibility, 1/2 statute miles, light snow, and mist.
Probable cause
the truck driver's failure to maintain clearance from the airplane and the boom operator's failure to adequately clear the boom from the airplane. Contributing to the accident was the low visibility due to snow and mist.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record DEN06IA034
- Event ID
- 20060126X00127
- Case number
- DEN06IA034
- 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: investigation status, coordinates. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: e3955f955a0aa8dbe9329bc6336e65fc98c5717ebf49a3bbc5079b9d100f9396; retrieved 2026-09-18T14:55:42.359Z.
- The NTSB's operator name is blank for N798UA; the operator shown is the name the NTSB's other records give its FAA operator code, UALA.