United Airlines Boeing B737-300 incident
Boeing B737-300 · Incident: airframe, component or system failure during takeoff
From an unrecorded airport to Denver International Airport (DEN)
Event
- NTSB case
- CHI90IA070
- 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
- Visual Meteorological Cond
Boeing B737-300
- 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
- N338UA
- 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
- Airframe, component or system failure
- 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
- Landing gear, parking brake › Locked
- Landing gear, tire › Failure, total
Approximate · Estimated position: the centre of Cedar Rapids, IA, the place the record names. Not the accident site.
NTSB narrative
ALL FOUR MAIN LANDING GEAR TIRES FAILED DURING THE TAKEOFF ROLL JUST PRIOR TO ROTATION. THE PARKING BRAKE HAD BEEN SET ON THE ICY RUNWAY TO DO AN ENGINE RUNUP. THE CAPTAIN STATED HE HAD RELEASED THE BRAKES AT THE BEGINNING OF THE ROLL, AND THE COPILOT SAID HE HAD HEARD THE BRAKES RELEASE. HOWEVER, NEITHER PILOT HAD CHECKED TO SEE IF THE RED PARKING BRAKE LIGHT WAS ON. POST INCIDENT INSPECTION REVEALED BOTH THE CAPTAIN'S AND COPILOT'S PARKING BRAKE ACTUATION RIGGING TO BE OUT OF ADJUSTMENT.
Probable cause
THE FAILURE OF ALL FOUR MAIN LANDING GEAR TIRES ON TAKEOFF DUE TO THE PARKING BRAKE BEING LOCKED.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CHI90IA070
- Event ID
- 20001212X22388
- Case number
- CHI90IA070
- 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: 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: e6a9b78d160c02c85de431dcda329b078c4d26493792663f1ddabb19bf2bd545; retrieved 2026-09-18T19:05:26.945Z.