# NTSB SEA91IA081: Boeing 737-222, N9003U, Seattle, WA, April 10, 1991

- Type: NTSB incident investigation
- Classification: Incident · Minor injuries · Incident investigation · Final report
- Date: April 9, 1991, 19:54 local (Apr 10, 1991, 02:54 UTC)
- Place: Seattle, WA
- Coordinates: 47.439373, -122.280845 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=47.4394&lon=-122.2808&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 2 minor, 31 uninjured
- Status: Completed, report May 5, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 41346
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA91IA081
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/41346/pdf
- Page: https://openairdocs.org/ntsb/SEA91IA081

## Probable cause

TURBINE BLADE FAILURE FROM FATIGUE.  FACTORS TO THE INCIDENT WERE INOPERATIVE ENGINE FIRE EXTINGUISHER, INADEQUATE SERVICE OF AIRCRAFT AND DELAYED DEPLOYMENT OF EMERGENCY SLIDE.

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Loss of engine power(total) - mech failure/malf, takeoff - initial climb
  - turbine assembly,turbine blade - fatigue (cause)
- Fire, takeoff - initial climb
  - fire extinguisher,powerplant - inoperative
  - maintenance,service of aircraft/equipment - inadequate, company maintenance personnel (contributing factor)
- Airframe/component/system failure/malfunction, standing - engine(s) not operating
  - misc eqpt/furnishings,slides - other (contributing factor)

## Analysis

DURING THE INITIAL CLIMB, THE FLIGHT CREW HEARD A LOUD BANG FOLLOWED BY AIRFRAME VIBRATIONS.  THE CREW WAS NOTIFIED BY THE CONTROL TOWER THAT SMOKE AND FLAME WERE EMITTING FROM THE LEFT ENGINE. THE FLIGHT CREW DECLARED AN EMERGENCY AND WAS CLEARED TO LAND.  THE PILOT DISCHARGED A BANK OF FIRE EXTINGUISHING AGENT AND SHUT THE ENGINE DOWN.  THE FLIGHT LANDED WITHOUT FURTHER INCIDENT.  DURING THE FOLLOW-UP INVESTIGATION, IT WAS FOUND THAT A TURBINE BLADE FAILED IN FATIGUE.  THE FLIGHT CREW HAD RECEIVED AN INDICTION THAT THE FIRE EXTINGUISHING AGENT HAD DISCHARGED, HOWEVER, IT WAS LATER FOUND THAT IT DIDN'T DUE TO THE INSTALLATION OF AN INCORRECT DISCHARGE OUTLET.  THE REAR EMERGENCY SLIDE ON THE RIGHT SIDE WAS SLOW IN INFLATING AND WAS NOT USABLE FOR THE EVACUATION.  THE SLIDE WAS INSTALLED ON A TEST STAND AND FOUND TO OPERATE WITHIN NORMAL OPERATING PARAMETERS.

## Aircraft

- Registration: [N9003U](https://openairdocs.org/deregistered/N9003U-1997-10-14), registration cancelled 1997-10-14, S/N 19041 (OpenAirDocs)
- Reported make and model: BOEING 737-222
- Registry model: [Boeing 737-222](https://openairdocs.org/model/boeing-737-222) (registry code 1384473) (OpenAirDocs)
- Category: Airplane
- Serial number: 19041
- Engines: P&W JT8D-7B 14500 lbs thrust turbo jet
- Damage: Minor damage
- Fire: In-Flight
- Flight: Part 121
- Operator: United Airlines
- Registered owner: United Airlines
- Destination: SMF, SACRAMENTO, CA
- Flight plan: IFR
- Airport: SEA, Seattle, runway 16, 9,425 × 150 ft, concrete

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 56; commercial, airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, unknown; flight hours: 14,075 total, 188 in the last 90 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 250° at 15 knots
- Visibility: 10 statute miles
- Temperature: -0 °F, dew point -0 °F

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Incident 19910409031729I](https://openairdocs.org/incident/19910409031729I), Apr 9, 1991: Boeing 737222, Seattle, WA, Minor damage. Left engine caught fire after departure. Returned. Evacuated on taxiway. Had one slide problem.

## Other investigations on N9003U (1)

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

- [NTSB DCA71IZ003](https://openairdocs.org/ntsb/DCA71IZ003), Dec 31, 1970: Boeing 737 (N9003U), Washington, DC, incident, substantial damage

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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