Seattle Airport
Aircraft Accident/Incident Report

Seattle, Washington 98188
Tuesady, April 9, 1991 19:54 PDT

NTSB Narrative Summary Released at Completion of Accident

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.

NTSB Probable Cause Narrative

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

Event Information

Type of Event Incident
Event Date 4/9/1991
Event Day of the Week Tuesday
Time of Event 1954
Event Time Zone Pacific Daylight Time
Event City SEATTLE
Event State WASHINGTON
Event Country --
Zipcode of the event site 98188
Event Date Year 1991
Event Date Month 4
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude
Event Location Longitude
Event Location Airport SEATTLE
Event Location Nearest Airport ID SEA
Indicates whether the acc/inc occurred off or on an airport On Airport
Distance from airport in statute miles 0
Degrees magnetic from airport 0
Airport Elevation 429
Weather Briefing Completeness Full
Investigator's weather source Witness
Time of the weather observation 0
Direction of event from weather observation facility (degrees) 0
Weather Observation Facility ID
Elevation of weather observation facility 0
Distance of event from weather observation facility (units?) 0
Time Zone of the weather observation
Lighting Conditions Day
Lowest Ceiling Height 0
Lowest Non-Ceiling Height 3000
Sky/Lowest/Cloud Conditions Scattered
Sky Condition for Lowest Ceiling Unknown
Visibility Runway Visual Range (Feet) 0
Visibility Runway Visual Value (Statute Miles) 0
Visibility (Statute Miles) 10
Air Temperature at event time (in degrees celsius) -18
Dew Point at event time (in degress fahrenheit) -18
Wind Direction (degrees magnetic) 250
Variable Wind Indicator Unknown
Wind Speed (knots) 15
Wind Velocity Indicator Unknown
Wind Gust Indicator Unknown
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) --
Density Altitude (feet) 0
Intensity of Precipitation Unknown
METAR weather report --
Event Highest Injury Minor
On Ground, Fatal Injuries 0
On Ground, Minor Injuries 0
On Ground, Serious Injuries 0
Injury Total Fatal --
Injury Total Minor 2
Injury Total None 31
Injury Total Serious --
Injury Total All 2
Investigating Agency NTSB
NTSB Docket Number (internal use) 5032
NTSB Notification Source --
NTSB Notification Date --
NTSB Notification Time 0
Fiche Number and/or location -used to find docket information 44378
Date of most recent change to record Dec 18 2002 11:28AM
User who most recently changed record NTSB\GIUV
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N9003U
NTSB Number SEA91IA081
Missing Aircraft Indicator N
Federal Aviation Reg. Part Part 121: Air Carrier
Type of Flight Plan filed IFR
Flight plan Was Activated? --
Damage Minor
Aircraft Fire In-flight
Aircraft Explosion In-flight
Aircraft Manufacturer's Full Name BOEING
Aircraft Model 737-222
Aircraft Series Identifier 737-222
Aircraft Serial Number 19041
Certified Max Gross Weight 100800
Aircraft Category Airplane
Aircraft Registration Class U.S. Registered/U.S. Soil
Aircraft is a homebuilt? No
Flight Crew Seats --
Cabin Crew Seats --
Passenger Seats --
Total number of seats on the aircraft 100
Number of Engines 2
Fixed gear or retractable gear Retractable
Aircraft, Type of Last Inspection Unknown
Date of Last Inspection --
Airframe hours since last inspection 0
Airframe Hours --
ELT Installed Yes
ELT Activated No
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name UNITED AIRLINES
Aircraft Owner Street Address P.O. BOX 66100
Aircraft Owner City CHICAGO
Aircraft Owner State IL
Aircraft Owner Country
Aircraft Owner Zipcode 60606
Operator is an individual? --
Operator Name UNITED AIRLINES
Operator Same as Owner? Yes
Operator Is Doing Business As --
Operator Address Same as Owner? Yes
Operator Street Address P.O. BOX 66100
Operator City CHICAGO
Operator State IL
Operator Country
Operator Zip code 60606
Operator Code UALA
Owner has at least one certificate Yes - certificate holder
Other Operator of large aircraft? No
Certified for Part 133 or 137 Operation Unknown
Operator Certificate Number --
Indicates whether an air carrier operation was scheduled or not Scheduled
Indicates Domestic or International Flight Domestic
Operator carrying Pax/Cargo/Mail Passenger Only
Type of Flying (Per_Bus / Primary) Unknown
Second Pilot on Board Yes
Departure Point Same as Event Yes
Departure Airport Code
Departure City
Departure State
Departure Country
Departure Time 1945
Departure Time Zone PDT
Destination Same as Local Flt --
Destination Airport Code SMF
Destination City SACRAMENTO
Destination State CA
Destination Country
Specific Phase of Flight Takeoff
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Jan 2 2001 10:30AM
User who most recently changed record dbo
Since inspection or accident --
Event Location Runway Number and Location 16
Runway Length 9425
Runway Width 150
Sight Seeing flight No
Air Medical Flight No
Medical Flight --