Boeing 747-422 N174UA
27 August 1990 · Los Angeles, California, United States · Minor injuries
Summary
On 27 August 1990 at about 17:25 local time, a Boeing 747-422 registered N174UA, operated by United Airlines, was involved in an incident near Los Angeles, California, United States. 345 people were on board and 23 had minor injuries. The aircraft was slightly damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.
The record
- Date
- at 17:25
- Classification
- Incident
- Location
- Los Angeles, California, United States
- Nearest airport
- Los Angeles Intl. (LAX)
- Coordinates
- 33.9500, -118.4008
- Aircraft
- Boeing 747-422
- Registration
- N174UA
- Category
- Airplane
- Engines
- 4
- Operator
- United Airlines
- Operating rule
- Part 121: Air Carrier
- Purpose of flight
- Unknown
- Phase of flight
- Not recorded
- Route
- Sydney → Unknown
- Aircraft damage
- Minor
- Weather
- VMC
- Light
- Day
- NTSB number
- LAX90IA305
People
23 people had minor injuries.
| On board | Died | Serious | Minor | Uninjured |
|---|---|---|---|---|
| 345 | 0 | 0 | 23 | 320 |
Probable cause
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.
Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.
Read the full NTSB narrative
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.
Quoted verbatim from the NTSB record.
Other Boeing 747 accidents
| Date | Aircraft | Location | Operator | Outcome | Died |
|---|---|---|---|---|---|
| 10 Jan 1990 | Boeing 747-151 | Detroit, Michigan, United States | Northwest Airlines, Inc. | No injuries | - |
| 14 Jul 1990 | Boeing 747-136 | Miami, Florida, United States | British Airways | Serious injuries | - |
| 16 Jun 1990 | Boeing 747-230 | Jamaica, New York, United States | - | No injuries | - |
| 15 Feb 1990 | Boeing 747-446B | Everett, Washington, United States | - | No injuries | - |
| 8 May 1989 | Boeing 747 | Los Angeles, California, United States | Air New Zealand | Minor injuries | - |
| 16 Jun 1991 | Boeing 747-400 | Philadelphia, Pennsylvania, United States | KLM Royal Dutch Airline | Serious injuries | - |
Other accidents in this area
| Date | Aircraft | Location | Operator | Outcome | Died |
|---|---|---|---|---|---|
| 15 Apr 1990 | Cessna 180 | Soledad, California, United States | - | No injuries | - |
| 10 Oct 1990 | Cessna 150 | Riverside, California, United States | PAR Flight | No injuries | - |
| 17 Apr 1990 | Piper PA46 | Paso Robles, California, United States | Piper Aircraft Corp. | No injuries | - |
| 7 Oct 1990 | Cessna 182M | Bakersfield, California, United States | - | No injuries | - |
| 1 Apr 1990 | Piper J-3 | Creston, California, United States | - | Minor injuries | - |
| 11 Oct 1990 | Bell 47G4 | Merced, California, United States | John W. Myers | Serious injuries | - |