Los Angeles Intl. Airport
Aircraft Accident/Incident Report

Los Angeles, California 90045
Monday, August 27, 1990 10:25 PDT

NTSB Narrative Summary Released at Completion of Accident

THE CREW NOTED THAT THE NOSE AND MAIN BODY GEAR INDICATED UP AND LOCKED AFTER NORMAL GEAR EXTENSION. THE CREW USED THE ALT GEAR EXTENSION PROCEDURE, WHICH WAS UNSUCCESSFUL. THE AIRCRAFT LANDED WITH THE NOSE AND MAIN BODY GEAR RETRACTED WHEN THE FLIGHT REACHED THE MIN FUEL STATE. EXAM OF THE AIRCRAFT REVEALED THAT THE SELECTOR VALVE FOR THE AFFECTED GEAR WAS IN THE UP AND LOCKED POSITION, AND THE BOLT WHICH CONNECTS THE VALVE ARM TO THE COCKPIT CONTROL CABLE SYSTEM WAS MISSING. THE BOLT FOR WING GEAR SELECTOR VALVE ARM WAS FOUND PARTIALLY BACKED OUT; THE NUT AND COTTER PIN WERE MISSING. THE AIRCRAFT WAS DELIVERED TO UNITED IN JAN OF 1990 AND HAD 2,952 FLT HRS AND 402 CYCLES. DETAILED REVIEW OF THE MAINT RECORDS PROVED THAT UNITED HAD NOT PERFORMED ANY MAINT ON THE LANDING GEAR SYSTEM. A SECOND ALT GEAR EXTENSION PROCEDURE INVOLVING DE-ENERGIZING THE HYDRAULIC SYSTEM FOR THE AFFECTED GEAR IS NOT PUBLISHED IN THE CREW MANUALS, TAUGHT DURING INITIAL TRAINING, NOR AVAILABLE ON ANY CHECKLIST.

NTSB Probable Cause Narrative

THE FAILURE OF THE MANUFACTURER TO ENSURE THAT THE LANDING GEAR SELECTOR VALVES AND THEIR ASSOCIATED DRUM LINK ASSEMBLIES WERE PROPERLY INSTALLED PRIOR TO DELIVERY OF THE AIRCRAFT. A FACTOR IN THE ACCIDENT WAS THE LACK OF INFORMATION AVAILABLE TO THE CREW CONCERNING THE SECONDARY ALTERNATE GEAR EXTENSION PROCDURE.

Event Information

Type of Event Incident
Event Date 8/27/1990
Event Day of the Week Monday
Time of Event 1025
Event Time Zone Pacific Daylight Time
Event City LOS ANGELES
Event State CALIFORNIA
Event Country --
Zipcode of the event site 90045
Event Date Year 1990
Event Date Month 8
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude
Event Location Longitude
Event Location Airport LOS ANGELES INTL.
Event Location Nearest Airport ID LAX
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 126
Weather Briefing Completeness Not pertinent
Investigator's weather source Weather Observation Facility
Time of the weather observation 1025 Pacific Daylight Time
Direction of event from weather observation facility (degrees) 0
Weather Observation Facility ID LAX
Elevation of weather observation facility 126
Distance of event from weather observation facility (units?) 0
Time Zone of the weather observation PDT
Lighting Conditions Day
Lowest Ceiling Height 0
Lowest Non-Ceiling Height 0
Sky/Lowest/Cloud Conditions Clear
Sky Condition for Lowest Ceiling None
Visibility Runway Visual Range (Feet) 0
Visibility Runway Visual Value (Statute Miles) 0
Visibility (Statute Miles) 12
Air Temperature at event time (in degrees celsius) 24
Dew Point at event time (in degress fahrenheit) 13
Wind Direction (degrees magnetic) 250
Variable Wind Indicator Unknown
Wind Speed (knots) 10
Wind Velocity Indicator Unknown
Wind Gust Indicator Not Gusting
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) 30
Density Altitude (feet) 0
Intensity of Precipitation Unknown
METAR weather report --
Event Highest Injury Minor
On Ground, Fatal Injuries 0
On Ground, Minor Injuries 2
On Ground, Serious Injuries 0
Injury Total Fatal --
Injury Total Minor 25
Injury Total None 320
Injury Total Serious --
Injury Total All 25
Investigating Agency NTSB
NTSB Docket Number (internal use) 5032
NTSB Notification Source --
NTSB Notification Date Aug 27 1990 12:00AM
NTSB Notification Time 1035
Fiche Number and/or location -used to find docket information 43528
Date of most recent change to record Dec 12 2000 5:16PM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N174UA
NTSB Number LAX90IA305
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 None
Aircraft Explosion None
Aircraft Manufacturer's Full Name BOEING
Aircraft Model 747-422
Aircraft Series Identifier 747-422
Aircraft Serial Number 24381
Certified Max Gross Weight 870000
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 348
Number of Engines 4
Fixed gear or retractable gear Retractable
Aircraft, Type of Last Inspection Continuous Airworthiness
Date of Last Inspection Aug 25 1990 12:00AM
Airframe hours since last inspection 31
Airframe Hours 2952
ELT Installed Yes
ELT Activated No
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name UNKNOWN
Aircraft Owner Street Address
Aircraft Owner City
Aircraft Owner State
Aircraft Owner Country
Aircraft Owner Zipcode
Operator is an individual? --
Operator Name UNITED AIRLINES
Operator Same as Owner? No
Operator Is Doing Business As --
Operator Address Same as Owner? No
Operator Street Address P.O. BOX 66100
Operator City CHICAGO
Operator State IL
Operator Country
Operator Zip code 60666
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 International
Operator carrying Pax/Cargo/Mail Passenger Only
Type of Flying (Per_Bus / Primary) Unknown
Second Pilot on Board Yes
Departure Point Same as Event No
Departure Airport Code ASSY
Departure City SYDNEY
Departure State OF
Departure Country
Departure Time 300
Departure Time Zone UTC
Destination Same as Local Flt crash at destination city
Destination Airport Code LAX
Destination City
Destination State
Destination Country
Specific Phase of Flight Landing
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 25R
Runway Length 12091
Runway Width 150
Sight Seeing flight No
Air Medical Flight No
Medical Flight --