United Air Lines Flight 146
Boeing 757-222 · Incident: fire/smoke (non-impact) while standing
Narrative check · The NTSB narrative appears to contradict this record's location. Values are shown as recorded, not corrected; compare with the narrative.
Event
- NTSB case
- ENG09IA007
- 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
- Not recorded
Boeing 757-222
- Aircraft type
- Boeing 757
- 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
- N570UA
- Operator
- United Air Lines
- Onboard fatalities
- Unknown
- Route
- From not recordedTo not recorded
- 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) start-up
- Defining eventThe 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
- Fire/smoke (non-impact)
- 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
- Aircraft › Aircraft power plant
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
A United Airlines Boeing 757-222, N570UA, experienced a tailpipe fire on the No. 2, right, engine, a Pratt & Whitney PW2037(M) during engine start at the Denver International Airport. The airplane's right wing in back of the engine and adjacent fuselage suffered minor damage. Interrogation of the cockpit engine display showed several faults related to the electronic engine control (EEC) burner pressure (Pb) sensors. The interrogation of the cockpit engine display also showed the Pb indications were abnormally high for an engine start. Fuel is scheduled to the an engine as a function of Pb. So a high Pb indication would consequently result in a high fuel flow to the engine. Because the engine was just starting, the limited amount of airflow through the engine was insufficient for the excessive amount of fuel and resulted in a tailpipe fire. The EEC was removed from the engine and sent to the manufacturer for testing. The testing could not identify a cause for the malfunction and subsequent tailpipe fire.
Probable cause
There was a malfunction of the electronic engine control (EEC) burner pressure (Pb) sensor that had an abnormally high indication that resulted in an excessive amount of fuel being pumped into the engine that was still at a sub-idle condition. Because the engine was still accelerating to idle, the limited airflow through the engine engine was insufficient for the amount of fuel and resulted in a tailpipe fire. The cause of the EEC's Pb sensor fault could not be determined.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record ENG09IA007
- Event ID
- 20090610X65600
- Case number
- ENG09IA007
- Dataset
- full-current
- Source SHA-256
- 5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
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, 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: 87ff9b7b0f8ea1667eea8a97b56f5907cd958f1bbc9daab298b1894761993373; retrieved 2026-09-15T11:22:23.991Z.