United Airlines Flight 475
Boeing 737-322 · Accident: on ground/water collision with object during pushback
From Denver International Airport (DEN) to Ontario International Airport (ONT)
Event
- NTSB case
- FTW98FA273
- 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
- Accident
- 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
- Visual 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
- N364UA
- Operator
- United Airlines
- Onboard fatalities
- Unknown
- Route
- From Denver International Airport (DEN)To Ontario International Airport (ONT), Ontario, CA
- 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
- Pushback/towing
- 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
- Substantial
Cause areas
- Ground personnel › Visual lookout, inadequate
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The catering truck driver parked directly behind the airplane, awaiting the arrival of another flight at an adjacent gate. He set the parking brake, turned off the engine, but left the headlights on. He said he was not concerned about parking behind the airplane because the jetway was still in position, the airplane's rotating beacon was not flashing, and another catering truck was servicing the coach section. The other truck then moved around to the front of the airplane to service the first class section. After baggage had been loaded in the forward cargo bin, the belt loader was backed away from the airplane. Normally, the belt loader would then be positioned on the vehicle service road to warn traffic that an airplane was being pushed back. This was not possible because the belt loader was blocked by the catering truck that had backed away from the airplane. The tug operator had made a previous walk-around inspection of the airplane and observed no hazards. He said that prior to pushback, he looked under the airplane one more time and saw no obstacles. He said he did not see the parked catering truck. As the catering truck was backing away from the airplane, pushback began and the airplane collided with the parked catering truck.
Probable cause
Inadequate visual lookout by ground personnel (tug operator). Factors include failure of the airline to provide proper assistance (wing walkers) to the tug operator, and inadequate pushback procedures by the airline; inattention of the catering truck driver, and failure of the flight crew to illuminate the rotating beacon prior to or during pushback.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record FTW98FA273
- Event ID
- 20001211X10292
- Case number
- FTW98FA273
- 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. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 1998-06-18.
- API snapshot SHA-256: 0208ad14aa062b4ca0c020055b1d9a10557d3c6bc294dcdf34b2d1bef917e2e1; retrieved 2026-09-18T17:07:54.712Z.
- The NTSB's operator name is blank for N364UA; the operator shown is the name the NTSB's other records give its FAA operator code, UALA.