Engine Fire and Extinguisher Malfunction During Initial Climb

Casualties unknown • Seattle, WA, US

An engine fire occurred during the initial climb of a flight, leading to an emergency landing where it was discovered that the fire extinguishing agent failed to discharge.

What happened

During the initial climb phase of the flight, the crew experienced a loud bang followed by significant airframe vibrations. The control tower notified the flight crew that smoke and flames were visible emitting from the left engine.

In response to the situation, the crew declared an emergency and received clearance to land. The pilot attempted to discharge a bank of fire extinguishing agent and subsequently shut down the affected engine. The aircraft landed without further incident, and there were no injuries reported.

The investigation

A follow-up investigation into the engine failure revealed that a turbine blade failed due to fatigue.

While the flight crew received an indication that the fire extinguishing agent had been successfully discharged, investigators determined that the agent did not actually exit the system. This failure was attributed to the installation of an incorrect discharge outlet.

Additionally, the investigation noted that the rear emergency slide on the right side of the aircraft was slow to inflate, rendering it unusable for evacuation. However, when the slide was later tested on a test stand, it was found to operate within normal operating parameters.

Probable cause

The failure of a turbine blade due to fatigue caused the engine fire and subsequent vibrations.

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Frequently asked questions

What happened in the 1991-04-10 Boeing 737-222 accident near Seattle, WA?

An engine fire occurred during the initial climb of a flight, leading to an emergency landing where it was discovered that the fire extinguishing agent failed to discharge.

What aircraft was involved and where did it happen?

The accident on 1991-04-10 involved a Boeing 737-222, registration N9003U, operated by United Airlines, at Seattle, WA.

What was the probable cause of the accident?

The failure of a turbine blade due to fatigue caused the engine fire and subsequent vibrations.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001212X16879. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.

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