Northwest Airlines Boeing 727-257 incident
Boeing 727-257 · Incident before flight
From Seattle–Tacoma International Airport (SEA) to an unrecorded destination
Event
- NTSB case
- CHI91IA041
- 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 727-257
- Aircraft type
- Boeing 727
- 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
- N715RC
- Operator
- Northwest Airlines
- Onboard fatalities
- Unknown
- Route
- From Seattle–Tacoma International Airport (SEA), Seattle, WATo 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
- Prior to flight
- 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
- Miscellaneous/other
- 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
- Company/operator management › Procedure inadequate
Approximate · Estimated position: the centre of Detroit, MI, the place the record names. Not the accident site.
NTSB narrative
THE INCIDENT AIRPLANE EXPERIENCED AN APU FIRE SHORTLY AFTER LANDING WHEN THE APU WAS STARTED. THE AIRPLANE HAD BEEN DEICED AT ITS POINT OF DEPARTURE WITH A GLYCOL AND WATER MIX. COMPANY POLICY CALLED FOR THE FLIGHT CREW TO SHUT OFF THE APU DURING DEICING. THE APU EXHAUST OUTLET IS ON TOP OF THE RIGHT WING NEAR THE FUSELAGE, AND WILL ACCEPT DEICE FLUID INTO THE EXHAUST AND SUBSEQUENTLY THE APU COMBUSTION CHAMBER IF DEICING FLUID IS DIRECTED INTO THE OPENING. GLYCOL IS HIGHLY FLAMMABLE ONCE THE WATER IS VAPORIZED/EVAPORATED. THE APU START FOLLOWING THE LANDING AT DETROIT IGNITED THE RESIDUAL GLYCOL IN THE APU, CAUSING THE EXHAUST STACK FIRE.
Probable cause
THE INADEQUATE DEICING PROCEDURES INSTITUTED BY COMPANY MANAGEMENT.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CHI91IA041
- Event ID
- 20001212X24734
- Case number
- CHI91IA041
- 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: d5823eecbea10a438f96bedeb09f308c349ffd12e484e289510c020e41558da1; retrieved 2026-09-18T18:58:08.565Z.