United Airlines Boeing 777-222 accident
Boeing 777-222 and American Airlines McDonnell Douglas MD 83 · Accident: on ground/water collision with object while taxiing
Event
- NTSB case
- CHI07FA184
- 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
- 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
Aircraft 1 · Boeing 777-222
- 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
- N213UA
- Operator
- United Airlines
- Onboard fatalities
- Unknown
- Route
- From Chicago O'Hare International Airport (ORD), Chicago, ILTo San Francisco International Airport (SFO), San Francisco, 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
- Taxi
- 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
Aircraft 2 · McDonnell Douglas MD 83
- Aircraft type
- McDonnell Douglas MD-83
- 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
- N9630A
- Operator
- American Airlines
- Onboard fatalities
- Unknown
- Route
- From Chicago O'Hare International Airport (ORD), Chicago, ILTo Seattle–Tacoma International Airport (SEA), Seattle, WA
- 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
- 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
- Airport personnel › Instructions, written/verbal, not coordinated/diseminated
- Flightcrew of other aircraft › Clearance, not maintained
- Flightcrew › Clearance, not maintained
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
Due to a weather hold, a McDonnell Douglas MD 83 was given clearance by Air Traffic Controllers (ATC) to park in a hold pad. A Boeing 777-222 was given similar ATC instruction. Rain and a micro burst were reported in the area obscuring visibility while taxiing. The runway 9R hold pad chart indicated that "pilots exercise caution taxiing past hold pad with parked aircraft - maintain centerline. Entire aircraft must be contained inside pad boundary line/lights." The 777-222 captain stated that he maintained the taxiway centerline while taxiing. The 777-222's flight crew used flight handbook reference points to remain clear of the parked airplanes. However, the 777-222's right wing impacted the MD 83's rudder. Wreckage on the ground was consistent with the MD 83 not fully parked within the hold pad. An ATC representative reported that ATC had received no guidance from the airport certificate holder on the entry and exit of airplanes on the 9R hold pad. The area encircling the hold pad was marked as taxiway. Taxiway Mike (M) borders the south area of the 9R hold pad and taxiway Kilo (K) borders the north area of the 9R hold pad.
Probable cause
The 777-222's flight crew not maintaining clearance from the parked/standing MD 83 and the airport not coordinating the taxi chart instructions with air traffic control. Contributing to the accident was the MD 83's flight crew not following the taxi chart instructions to fully park within the pad and the reduced visual lookout due to the weather.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CHI07FA184
- Event ID
- 20070705X00879
- Case number
- CHI07FA184
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
Source notes (6)
- 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. 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: da6798e122490ba511f0e3bdc71b2cf0ea19419c10c6290250e4ac8615632c3a; retrieved 2026-09-18T14:43:29.955Z.
- The NTSB's operator name is blank for N213UA; the operator shown is the name the NTSB's other records give its FAA operator code, UALA.
- The NTSB's operator name is blank for N9630A; the operator shown is the name the NTSB's other records give its FAA operator code, AALA.