Boeing 737-277 and Boeing 747SP accident near Los Angeles, California, June 23, 1987
On June 23, 1987 at about 3:39 am local time, 2 aircraft, Boeing 737-277 (N184AW) and Boeing 747SP (N141UA), were involved in the same accident near Los Angeles, California (Los Angeles Int'L airport). No one was hurt; 83 people were on board or involved. The weather was conditions the NTSB did not record.
The NTSB's probable cause their words, unchanged
FAILURE OF THE QUALIFIED MECHANIC TO INSURE THE OPERATION OF THE AIRCRAFT BRAKES PRIOR TO TAXIING AND HIS FAILURE TO UTILIZE THE EMERGENY BRAKE SYSTEM TO PREVENT THE COLLISION. CONTRIBUTING TO THIS ACCIDENT WAS THE DECISION OF AIRLINE MAINTENANCE SUPERVISORS TO ALLOW A NON-QUALIFIED MECHANIC TO PERFORM RIGHT SEAT/FLIGHT ENGINEER PANEL DUTIES. ALSO CONTRIBUTING WAS THE QUALIFIED MECHANICS FAILURE TO USE THE AIRCRAFT'S INERTIAL NAVIGATION SYSTEM FOR CROSS REFERENCE OF TAXI SPEED.
FAILURE OF THE QUALIFIED MECHANIC TO INSURE THE OPERATION OF THE AIRCRAFT BRAKES PRIOR TO TAXIING AND HIS FAILURE TO UTILIZE THE EMERGENCY BRAKE SYSTEM TO PREVENT THE COLLISION. CONTRIBUTING TO THIS ACCIDENT WAS THE DECISION OF AIRLINE MAINTENCE SUPERVISORS TO ALLOW A NON QUALIFIED MECHANIC TO PERFORM RIGHT SEAT/FLIGHT ENGINEER PANEL DUTIES. ALSO CONTRIBUTING WAS THE QUALIFIED MECHANICS FAILURE TO USE THE AIRCRAFT'S INERTIAL NAVIGATION SYSTEM FOR CROSS REFERENCE TO TAXI SPEED.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 23, 1987 · about 3:39 am local time
- Place
- Los Angeles, California · Los Angeles Int'L
- Type
- Accident · collision on the ground
- Injuries
- No one was hurt; 83 people were on board or involved.
- Weather
- conditions the NTSB did not record
- Aircraft 1
- Boeing 737-277 · all 737-277s on the register
- Registration
- N184AW · no longer on the register · serial 22651
- Damage
- Substantial damage
- Flight
- Flight of an unrecorded kind · scheduled airline rules (Part 121)
- Aircraft 2
- Boeing 747SP · all 747SPs on the register
- Registration
- N141UA · no longer on the register · serial 21023
- Damage
- Substantial damage
- Flight
- Flight of an unrecorded kind · scheduled airline rules (Part 121)
The NTSB's narrative for the Boeing 737-277 final · quoted from the NTSB record
A BOEING 747SP COLLIDED WITH THE TAIL OF A BOEING 737. THE 737 WAS LINED UP ON A PARALLEL TAXIWAY AWAITING DEPARTURE. THE 747 WAS TAXIING FROM A TERMINAL GATE TO MAINTENANCE. THE 747 WAS BEING OPERATED BY TWO MECHANICS. ONE OF THE MECHANICS WAS NOT QUALIFIED TO TAXI THE 747. NO. 4 ENG HUNG START AND WAS NOT RUNNING DURING TAXI. THE NO. 4 ENG HYD SYS WAS SWITCHED OFF. THE NO. 4 HYD SYS IS THE PRIMARY POWER FOR THE ACFT BRAKE SYS. THE 747'S INERTIAL NAV SYS (INS) IS REQUIRED TO OPERATE WHILE TAXIING FOR SPEED REFERENCE. THE INS WAS ALSO SWITCHED OFF. THE 747 SPEED BECAME EXCESSIVE ON PARALLEL TAXIWAY. WHEN MECH ATTEMPTED TO STOP THERE WAS NO BRAKE POWER. 747 R WING COLLIDED WITH TAIL OF 737. THE AIRLINE MAINT SUPERVISOR OF 747'S WAS AWARE OF THE MECH NON-QUAL AND THE NO. 4 ENG NOT OPERATING. DECISION WAS MADE TO LET THE ACFT TAXI CONTRARY TO PROCEDURES.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The NTSB's narrative for the Boeing 747SP final · quoted from the NTSB record
A BOEING 747SP COLLIDED WITH THE TAIL OF A BOEING 737. THE 737 WAS LINED UP ON A PARALLEL TAXIWAY AWAITING DEPARTURE. THE 747 WAS TAXIING FROM A TERMINAL GATE TO MAINTENANCE. THE 747 WAS BEING OPERATED BY TWO MECHANICS. ONE OF THE MECHANICS WAS NOT QUALIFIED TO TAXI THE 747. NO. 4 ENG HUNG START AND WAS NOT RUNNING DURING TAXI. THE NO. 4 ENG HYD SYS WAS SWITCHED OFF. THE NO. 4 HYD SYS IS THE PRIMARY POWER FOR THE ACFT BRAKE SYS. THE 747'S INERTIAL NAV SYS (INS) IS REQUIRED TO OPERATE WHILE TAXIING FOR SPEED REFERENCE. THE INS WAS ALSO SWITCHED OFF. THE 747 SPEED BECAME EXCESSIVE ON PARALLEL TAXIWAY. WHEN MECH ATTEMPTED TO STOP THERE WAS NO BRAKE POWER. HE DID NOT ACTIVATE THE EMER BRAKE SYS POWERED BY NO. 2 ENG HYD SYS. THE MECH SWERVED THE 747 TO THE LEFT. THE 747 R WING COLLIDED WITH TAIL OF 737. THE AIRLINE MAINT SUPERVISOR OF 747'S WAS AWARE OF MECH NON-QUAL AND OF THE NO. 4 ENG NOT OPERATING. DECISION WAS MADE TO LET THE ACFT TAXI CONTRARY TO PROCEDURES.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record for the Boeing 737-277 from the NTSB's investigation tables, in plain English
Pilot
- Certificate: airline transport pilot, flight instructor, commercial pilot
- Ratings: multi-engine land; single-engine land; instructor: airplane single-engine; instrument: airplane
- Flight time: 6,271 hours in all; 1,320 in this make and model; 266 in the last 90 days
- Medical certificate: Class 1 (valid medical--no waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 13,290 hours
- Last inspection: continuous airworthiness programme; 102 hours since
- Maximum gross weight: 110,000 lb
- Seats: 122
- Landing gear: retractable
- Engine: P&W JT8D-15 (turbofan); 0 hours total
- Operator: America West Airlines
The flight
- Destination: PHX Phoenix AZ
- Flight plan: IFR
- Runway 0
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 250° at 8 knots
- Visibility: 8 statute miles
- Sky: not recorded; not recorded
- Temperature: 64°F (18°C), dew point 63°F (17°C)
- Altimeter: 29.00 inHg
- Observation at 3:42 am from LAX
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 5 | |||
| Passengers | 76 |
The factual record for the Boeing 747SP from the NTSB's investigation tables, in plain English
Pilot
- Medical certificate: None
- Seat: left
The aircraft
- Airframe total time: 52,233 hours
- Last inspection: continuous airworthiness programme; 171 hours since
- Maximum gross weight: 775,000 lb
- Seats: 233
- Landing gear: retractable
- Engine: P&W JT9D-7 (turbofan); 0 hours total
- Operator: United Airlines
The flight
- Flight plan: none
- Runway 0
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 2 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.