# NTSB WPR11LA300: Boeing 757-222, N526UA, Los Angeles, CA, May 31, 2011 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Limited investigation · Final report - Date: May 31, 2011, 12:15 local (19:15 UTC) - Place: Los Angeles, CA - Coordinates: 33.938888, -118.404724 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=33.9389&lon=-118.4047&mi=10 - Phase of flight: [Pushback/towing](https://openairdocs.org/ntsb-phases/200) (OpenAirDocs' grouping) - Defining event: [Pushback/tow-engine not oper: Ground handling event](https://openairdocs.org/ntsb-events/080) - Highest injury: Serious injuries - Injuries: 1 serious, 190 uninjured; on the ground: 1 serious - Status: Completed, report November 7, 2012 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration, United Airlines - NTSB case key (mKey): 80953 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR11LA300 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/80953/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=80953 - Page: https://openairdocs.org/ntsb/WPR11LA300 ## Probable cause The ground crewmembers’ failure to follow proper procedures for removing a stuck or jammed tow bar, which resulted in a ground crew injury. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Use of equip/info: use of policy/procedure](https://openairdocs.org/ntsb-findings/02063032): Personnel issues › Task performance · Ground crew (probable cause); cases with it: [Boeing 757-222, 1 case](https://openairdocs.org/ntsb-findings/02063032/cases.md?model=1384956), [All aircraft, 191 cases](https://openairdocs.org/ntsb-findings/02063032/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Pushback/tow-engine not oper: Ground handling event](https://openairdocs.org/ntsb-events/080) (defining event); cases with it: [Boeing 757-222, 1 case](https://openairdocs.org/ntsb-events/080/sequence.md?model=1384956), [All aircraft, 108 cases](https://openairdocs.org/ntsb-events/080/sequence.md) - [Standing-engine(s) not oper: Ground handling event](https://openairdocs.org/ntsb-events/080); cases with it: [Boeing 757-222, 1 case](https://openairdocs.org/ntsb-events/080/sequence.md?model=1384956), [All aircraft, 108 cases](https://openairdocs.org/ntsb-events/080/sequence.md) ## Analysis The tug’s tow bar’s shear pins broke while the airplane was being pushed back from the gate to an adjacent alley (a “turn reversal”), which required a significant (but within limits) turn of the nose landing gear. The tow bar became stuck and, despite repeated attempts by the operator’s ground crew personnel, would not disconnect from the tug or the airplane. When the operator’s ground personnel asked the pilots to release the airplane’s parking brake to ease the tension on the tow bar, the pilots did so. The airplane rolled slightly forward, contacting and fracturing the foot of one of the ground crewmembers. Although the operator’s ground crew ramp service manual procedure and flight manual guidance specified that the airplane’s parking brakes should not be released to assist in releasing a stuck tow bar, the pilots stated that they released the brakes believing that they were going to resume pushback. As a result of a postaccident hazard assessment, the operator stopped performing turn reversal tow operations similar to the accident operation. ## Factual narrative On May 31, 2011, about 1215 Pacific daylight time, a Boeing 757-222, N526UA, operating as flight number 840, was being pushed back from the gate at the Los Angeles International Airport (LAX), Los Angeles, California, when, one of its nose wheel tires made contact with and trapped a ground crewmember's foot. The airplane's nose gear tire sustained minor damage while the ground crewmember sustained a serious foot injury. United Airlines was operating the domestic passenger flight from Los Angeles to Chicago, Illinois, under the provisions of Title 14 Code of Federal regulations Part 121. There were 182 passengers on board, along with six cabin crewmembers and two airline transport certificated pilots. Representatives from United Airlines reported the accident occurred as the airplane was being turned to a nose out position in the alley, adjacent to the dispatch gate. The tow bar's shear pins broke during the turn, and additional ground personnel arrived on scene to assist in removing the tow bar and its respective pins. The position of the tow bar was about at an 80 degree angle, but not past the limit, as marked on the airplane nose landing gear door. The flight crew was requested to set the brakes and attempts to release the tow bar from the tractor and airplane were initially unsuccessful. Proper company tow bar removal procedures for abnormal conditions were not referenced by ground personnel during these efforts. In an attempt to relieve tension on the tow bar, ground personnel requested the flight crew to release the parking brakes. Although, the company flight manual has a caution for flight crews not to release the parking brakes to assist in releasing a stuck tow bar, the flight crew complied with the ground crew’s request. The flight crew assumed they were resuming the pushback since they were not made aware of any difficulty in removing the tow bar. The airplane brakes were released while ground personnel attempted to release the tow bar. Attempts to open the locking handle on the tow bar were successful and the tow bar immediately dropped to the ramp. The airplane rolled slightly forward and overran the tow bar and then made contact with and trapped one of the assisting ground personnel's foot before coming to a stop. Post accident inspection revealed no mechanical discrepancies in the airplane braking system. ## Aircraft - Registration: [N526UA](https://openairdocs.org/deregistered/N526UA-2019-02-23), registration cancelled 2019-02-23, S/N 24994, built 1991 (OpenAirDocs) - Reported make and model: BOEING 757-222 - Registry model: [Boeing 757-222](https://openairdocs.org/model/boeing-757-222) (registry code 1384956) (OpenAirDocs) - Registry engine: [Pratt & Whitney PW2040](https://openairdocs.org/engine/pratt-whitney-pw2040) (registry code 52121, turbo-fan) (OpenAirDocs) - Category: Airplane - Serial number: 24994 - Airframe hours: 67211 - Engines: P & W PW2040 40900 lbs thrust turbo fan; P & W PW2040 40900 lbs thrust turbo fan - Damage: Minor damage - Flight: Part 121 - Operator: United Airlines - Registered owner: Wells Fargo Bank Northwest Na Trustee - Airworthiness certificate: Standard, Transport - Last inspection: Continuous airworthiness, May 23, 2011 - Departed: LAX, Los Angeles, CA - Destination: ORD, Chicago, IL - Flight plan: IFR - Airport: LAX, Los Angeles Intl. ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 52; injuries: none; commercial, airline transport; airplane ratings: multi-engine land; instrument ratings: airplane; medical: class 1, unknown; last flight review March 1, 2011; seat: left; flight hours: 11,829 total, 4,810 in this make and model, 3,445 as pilot in command, 88 in the last 90 days, 45 in the last 30 days, 7 in the last 24 hours - Co-pilot; age 47; injuries: none; commercial, airline transport; airplane ratings: multi-engine land; instrument ratings: airplane; medical: class 1, unknown; last flight review May 1, 2011; seat: right; flight hours: 10,064 total, 1,794 in this make and model, 2,399 as pilot in command, 236 in the last 90 days, 69 in the last 30 days, 0 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Visibility: 10 statute miles - Lowest ceiling: none ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20110531013149A](https://openairdocs.org/incident/20110531013149A), May 31, 2011: Boeing 757-222, Los Angeles, CA, Minor damage. During push-back for takeoff, towbar pin sheared and aircraft nose wheel rolled over a ground crewmember's foot. ## Other investigations on N526UA (2) 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. - [NTSB ENG11IA051](https://openairdocs.org/ntsb/ENG11IA051), Sep 26, 2011: Boeing 757-222 (N526UA), Denver, CO, incident, minor damage. Probable cause: **This probable cause was modified on 4/5/2012. Please see the public docket for this accident to view the original probable cause.** The initial damage to the fan blades was caused by the ingestion… - [NTSB SEA04IA175](https://openairdocs.org/ntsb/SEA04IA175), Aug 27, 2004: Boeing 757-200 (N526UA), Richmond, BC, Canada, incident, minor damage. Probable cause: The slat was impacted by birds after takeoff and subsequently the slat delaminated due to flight loads. ## Docket (8 files) The files NTSB released with the investigation on September 12, 2012, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=80953. 2.0 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 1.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40372321&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Witness Statement (item 2, .PDF, 47 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40372323&FileExtension=.PDF&FileName=Witness%20Statement-Redacted.PDF - Record of Email (Dr. Mitch Garber) (item 3, .PDF, 68 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40372336&FileExtension=.PDF&FileName=Record%20of%20Email%20(Dr.%20Mitch%20Garber)-Master.PDF - Record of Email (United Airlines) (item 4, .PDF, 33 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40373668&FileExtension=.PDF&FileName=Record%20of%20Email%20(United%20Airlines)-Master.PDF - Reports from Parties to the Investigation (item 5, .PDF, 17 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40372337&FileExtension=.PDF&FileName=Reports%20from%20Parties%20to%20the%20Investigation-Master.PDF - General Ramp Procedures, Chapter 11, Paragraph 22 (item 6, .PDF, 244 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40376489&FileExtension=.PDF&FileName=General%20Ramp%20Procedures,%20Chapter%2011,%20Paragraph%2022-Master.PDF - B-757 Company Flight Manual, Section 10-30-1 (item 7, .PDF, 192 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40376092&FileExtension=.PDF&FileName=B-757%20Company%20Flight%20Manual,%20Section%2010-30-1-Master.PDF - Statement of Party Representatives to NTSB Investigation (item 8, .PDF, 99 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40372322&FileExtension=.PDF&FileName=Statement%20of%20Party%20Representatives%20to%20NTSB%20Investigation-Redacted.PDF 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.