# NTSB LAX87LA243: Boeing 737-277, N184AW, Los Angeles, CA, June 23, 1987 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: June 22, 1987, 20:39 local (Jun 23, 1987, 03:39 UTC) - Place: Los Angeles, CA - Location: 33.9425° N, 118.4080° W: Placed by OpenAirDocs at LOS ANGELES INTL (LAX), within about a mile (OpenAirDocs) - Nearby events: https://openairdocs.org/map.md?lat=33.9425&lon=-118.4080&mi=10 - Phase of flight: [Standing](https://openairdocs.org/ntsb-phases/150) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 83 uninjured - Status: Completed, report November 28, 1989 - Report: Approved by Office Director - NTSB case key (mKey): 25616 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX87LA243 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/25616/pdf - Page: https://openairdocs.org/ntsb/LAX87LA243 ## Probable cause (aircraft 2) 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. ## Probable cause (aircraft 1) 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. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - On ground/water collision with object, standing - preflight planning/preparation - improper, pilot of other aircraft (cause) - brakes(normal) - improper use of, pilot of other aircraft (cause) - brakes(emergency) - not understood, pilot of other aircraft (contributing factor) - On ground/water collision with object, taxi - aircraft handling - improper, unqualified person (cause) - operation with known deficiencies in equipment - performed, company maintenance personnel (contributing factor) - navigation computer - not used, company maintenance personnel (contributing factor) - hydraulic system - not understood, company maintenance personnel (contributing factor) - brakes(normal) - inadvertent deactivation, company maintenance personnel (cause) - brakes(emergency) - not used, company maintenance personnel (cause) ## Analysis (aircraft 2) 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. ## Analysis (aircraft 1) 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. ## Aircraft 1 - Registration: [N184AW](https://openairdocs.org/deregistered/N184AW-2013-07-16), registration cancelled 2013-07-16, S/N 22651, built 1987 (OpenAirDocs) - Reported make and model: BOEING 737-277 - Registry model: [Boeing 737-277](https://openairdocs.org/model/boeing-737-277) (registry code 138447D) (OpenAirDocs) - Registry engine: [Amateur-built UNKNOWN ENG](https://openairdocs.org/engine/amateur-built-unknown-eng) (registry code 99999) (OpenAirDocs) - Category: Airplane - Serial number: 22651 - Airframe hours: 13290 - Engines: P&W JT8D-15 20550 lbs thrust turbo fan - Damage: Substantial damage - Flight: Part 121 - Operator: America West Airlines - Registered owner: America West Airlines - Airworthiness certificate: Standard, Transport - Destination: PHX, PHOENIX, AZ - Flight plan: IFR - Airport: LAX, Los Angeles Int'L ## Aircraft 2 - Registration: [N141UA](https://openairdocs.org/deregistered/N141UA-1996-01-05), registration cancelled 1996-01-05, S/N 21023 (OpenAirDocs) - Reported make and model: BOEING 747SP - Registry model: [Boeing 747SP-21](https://openairdocs.org/model/boeing-747sp-21) (registry code 1384802) (OpenAirDocs) - Category: Airplane - Serial number: 21023 - Airframe hours: 52233 - Engines: P&W JT9D-7 40000 lbs thrust turbo fan - Damage: Substantial damage - Flight: Part 121 - Operator: United Airlines, doing business as United Airlines - Registered owner: First Security Bank Of Utah - Airworthiness certificate: Standard, Transport - Airport: LAX, Los Angeles Int'L ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot, aircraft N184AW; age 31; commercial, airline transport, flight instructor; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 6,271 total, 1,320 in this make and model, 266 in the last 90 days - Pilot, aircraft N141UA; age 46; medical: unknown; seat: left ## Weather - Conditions: Day - Wind: 250° at 8 knots - Visibility: 8 statute miles - Temperature: 64 °F, dew point 63 °F - Altimeter: 29.00 inHg - Observed at: LAX ## FAA reports on this event (2) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 19870622055262A](https://openairdocs.org/incident/19870622055262A), Jun 22, 1987: Boeing 737277, Los Angeles, CA, Substantial damage. While holding on taxiway was struck by 747,N141UA,that a mechanic was taxiing without proper hydraulic brake system - [Accident 19870622055261A](https://openairdocs.org/incident/19870622055261A), Jun 22, 1987: Boeing 747SP21, Los Angeles, CA, Substantial damage. Mechanic taxiing 747 without brake hydraulic power struck a holding 737 N184AW. Had failed to use backup system. From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.