# NTSB DCA16CA207: Boeing 737 3H4, N368SW, Baltimore, MD, August 5, 2016 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: August 4, 2016, 21:02 local (Aug 5, 2016, 01:02 UTC) - Place: Baltimore, MD - Coordinates: 39, -76 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=39.0000&lon=-76.0000&mi=10 - Phase of flight: [Pushback/towing](https://openairdocs.org/ntsb-phases/200) (OpenAirDocs' grouping) - Defining event: [Pushback/towing: Ground handling event](https://openairdocs.org/ntsb-events/080) - Highest injury: No injuries - Injuries: 134 uninjured - Status: Completed, report January 23, 2017 - Report: Approved by Office Director - NTSB office: Major Investigations Division - NTSB case key (mKey): 93766 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DCA16CA207 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/93766/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=93766 - Page: https://openairdocs.org/ntsb/DCA16CA207 ## Probable cause the tug operators excessive speed during pushback. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Towing and taxiing: towing](https://openairdocs.org/ntsb-findings/01010910): Aircraft › Aircraft handling/service · Incorrect use/operation (probable cause); cases with it: [Boeing 737-3H4, 1 case](https://openairdocs.org/ntsb-findings/01010910/cases.md?model=138447K), [All aircraft, 10 cases](https://openairdocs.org/ntsb-findings/01010910/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Pushback/towing: Ground handling event](https://openairdocs.org/ntsb-events/080) (defining event); cases with it: [Boeing 737-3H4, 3 cases](https://openairdocs.org/ntsb-events/080/sequence.md?model=138447K), [All aircraft, 108 cases](https://openairdocs.org/ntsb-events/080/sequence.md) ## Analysis On August 4, 2016 at 9:02pm eastern daylight time, Southwest Airlines flight 149, a Boeing 737, N368SW, experienced a failure of the nose landing gear during pushback from the gate at the Baltimore/Washington Thurgood Marshall International Airport (BWI), Baltimore, Maryland. The aircraft was substantially damaged and there were no injuries to the 6 crewmembers or 129 passengers but the airplane was substantially damaged. The flight was being operated under 14 Code of Federal Regulation Part 121 as a regularly scheduled passenger flight to Atlanta-Hartsfield International Airport (ATL), Atlanta, Georgia. According to the flight crew, as the pushback tug was maneuvering the aircraft off the gate, the flight crew felt the front of the airplane bounce up and down, and then came to rest on the nose. The passengers were deplaned via air stairs. The nose gear collapsed in a forward direction, resulting in substantial damage to the gear structure, the nose gear well, and crushing the forward bulkhead. An airport surveillance camera video was obtained, which showed the tug pushing the aircraft at approximately 6 knots. The tug specifications indicate that speed could be achieved only in second gear or higher. The airline general operating manual specifies that pushback must be conducted in low or first gear, and at a walking speed. ## Factual narrative On August 4, 2016 at 9:02pm eastern daylight time, Southwest Airlines flight 149, a Boeing 737, N368SW, experienced a failure of the nose landing gear during pushback from the gate at the Baltimore/Washington Thurgood Marshall International Airport (BWI), Baltimore, Maryland. The aircraft was substantially damaged and there were no injuries to the 6 crewmembers or 129 passengers but the airplane was substantially damaged. The flight was being operated under 14 Code of Federal Regulation Part 121 as a regularly scheduled passenger flight to Atlanta-Hartsfield International Airport (ATL), Atlanta, Georgia. According to the flight crew, as the pushback tug was maneuvering the aircraft off the gate, the flight crew felt the front of the airplane bounce up and down, and then came to rest on the nose. The passengers were deplaned via air stairs. The nose gear collapsed in a forward direction, resulting in substantial damage to the gear structure, the nose gear well, and crushing the forward bulkhead. An airport surveillance camera video was obtained, which showed the tug pushing the aircraft at approximately 6 knots. The tug specifications indicate that speed could be achieved only in second gear or higher. The airline general operating manual specifies that pushback must be conducted in low or first gear, and at a walking speed. ## Aircraft - Registration: [N368SW](https://openairdocs.org/deregistered/N368SW-2018-03-22), registration cancelled 2018-03-22, S/N 26579, built 1993 (OpenAirDocs) - Reported make and model: BOEING 737 3H4 (3H4) - Registry model: [Boeing 737-3H4](https://openairdocs.org/model/boeing-737-3h4) (registry code 138447K) (OpenAirDocs) - Registry engine: [CFM International CFM56 series](https://openairdocs.org/engine/cfm-international-cfm56-series) (registry code 13802, turbo-fan) (OpenAirDocs) - Category: Airplane - Serial number: 26579 - Year built: 1993 - Airframe hours: 72354 - Engines: CFM INTL. CFM56 SERIES turbo fan; CFM INTL. CFM56 SERIES turbo fan - Damage: Substantial damage - Flight: Part 121 - Operator: Southwest Airlines - Registered owner: Southwest Airlines - Airworthiness certificate: Standard, Transport - Last inspection: July 28, 2016 - Departed: KBWI, Baltimore, MD - Destination: KATL, Atlanta, GA - Flight plan: IFR - Airport: KBWI, Baltimore/Thurgood Marshall In - Equipment: Heads up display, Onboard weather, Satellite tracking device, Stall warning system, ADS-B, Angle of attack indicator, Data recorder ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 51; injuries: none; airline transport; airplane ratings: multi-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review June 8, 2016; seat: left; restraint: 4-point; flight hours: 20,000 total, 16,000 in this make and model, 15,200 as pilot in command, 190 in the last 90 days, 50 in the last 30 days, 9 in the last 24 hours - Co-pilot; age 45; injuries: none; airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review April 22, 2016; seat: right; restraint: 4-point; flight hours: 13,800 total, 7,000 in this make and model, 9,000 as pilot in command, 120 in the last 90 days, 9 in the last 30 days, 9 in the last 24 hours ## Weather - Conditions: Visual (VMC), Night - Wind: 170° at 4 knots - Visibility: 10 statute miles - Lowest ceiling: 25,000 ft - Temperature: 79 °F, dew point 63 °F - Altimeter: 30.06 inHg - Observed at: KBWI ## 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 20160804013139A](https://openairdocs.org/incident/20160804013139A), Aug 4, 2016: Boeing 737-3H4, Baltimore, MD, Substantial damage. During aircraft pushback the tug applied brakes and the aircraft's nose landing gear collapsed. ## Other investigations on N368SW (1) 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 SEA04IA045](https://openairdocs.org/ntsb/SEA04IA045), Feb 24, 2004: Boeing 737-300 (N368SW), Seattle, WA, incident, no damage. Probable cause: The First Officer's misidentification of the parallel taxiway as the active runway, resulting in the need for a sidestep maneuver while on short final for a full-stop landing. Factors include… ## Docket (7 files) The files NTSB released with the investigation on January 25, 2017, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=93766. 6.9 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 599 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40458610&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Employee Statements (item 2, .PDF, 32 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40448593&FileExtension=.PDF&FileName=Employee%20Statements-Master.PDF - Pushback Tug Instructions (item 3, .PDF, 117 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40448594&FileExtension=.PDF&FileName=Pushback%20Tug%20Instructions-Master.PDF - Pushback Tug Specs (item 4, .PDF, 41 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40448595&FileExtension=.PDF&FileName=Pushback%20Tug%20Specs-Master.PDF - Damage Assessment (item 5, .PDF, 83 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40448596&FileExtension=.PDF&FileName=Damage%20Assessment-Master.PDF - Photos of Damage (item 6, .PDF, 2 photos, 5.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40452869&FileExtension=.PDF&FileName=Photos%20of%20Damage-Master.PDF - Video snapshots (item 7, .PDF, 3 photos, 313 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40452870&FileExtension=.PDF&FileName=Video%20snapshots-Master.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.