# NTSB DCA14CA093: Mcdonnell Douglas MD90 - 30, N933DN, Boston, MA, May 12, 2014 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: May 12, 2014, 19:30 local (23:30 UTC) - Place: Boston, MA - Coordinates: 42.363334, -71.023056 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=42.3633&lon=-71.0231&mi=10 - Phase of flight: [Pushback/towing](https://openairdocs.org/ntsb-phases/200) (OpenAirDocs' grouping) - Defining event: [Pushback/tow-engine not oper: Landing gear collapse](https://openairdocs.org/ntsb-events/094) - Highest injury: No injuries - Injuries: 166 uninjured - Status: Completed, report March 30, 2020 - Report: Approved by Office Director - NTSB office: Major Investigations Division - NTSB case key (mKey): 89211 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DCA14CA093 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/89211/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=89211 - Page: https://openairdocs.org/ntsb/DCA14CA093 ## Probable cause the captain's failure to verify the communications between himself and the tug operator, which resulted in him applying of brakes while the airplane was being pushed back from the gate by the tug with tow bar attached. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Attention/monitoring: monitoring communications](https://openairdocs.org/ntsb-findings/02021530): Personnel issues › Psychological · Pilot (probable cause); cases with it: [Mcdonnell Douglas MD-90-30, 1 case](https://openairdocs.org/ntsb-findings/02021530/cases.md?model=3023690), [All aircraft, 8 cases](https://openairdocs.org/ntsb-findings/02021530/cases.md) - [Action: incorrect action selection](https://openairdocs.org/ntsb-findings/02041010): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Mcdonnell Douglas MD-90-30, 1 case](https://openairdocs.org/ntsb-findings/02041010/cases.md?model=3023690), [All aircraft, 397 cases](https://openairdocs.org/ntsb-findings/02041010/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: Landing gear collapse](https://openairdocs.org/ntsb-events/094) (defining event); cases with it: [Mcdonnell Douglas MD-90-30, 1 case](https://openairdocs.org/ntsb-events/094/sequence.md?model=3023690), [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md) ## Analysis On May 12, 2014, at about 1737 eastern daylight time (EDT), Delta Airlines flight 1612, a Boeing MD-90, N933DN, experienced a partially collapsed nose gear during pushback from the gate at Boston Logan International Airport (KBOS), Boston, Massachusetts. The passengers and crew exited the aircraft via the jet bridge and there were no injuries. The flight was operating as a 14 Code of Federal Regulations Part 121 regularly scheduled passenger flight between KBOS and Minneapolis-Saint Paul International Airport (KMSP), Minneapolis, Minnesota. According to the flight crew, during pushback they received a new route clearance due to weather along the route. The captain and first officer discussed how they would handle the associated tasks, and agreed they would load the new route and then contact dispatch after the engine start had been accomplished. The crew stated the interphone conversation quality was degraded due to low volume, and there was considerable radio traffic on both clearance delivery and ramp frequencies. As the flight crew finished coordinating tasks, the captain heard on the interphone what he believed was "set brakes" and, because he did not discern any aircraft motion, began to apply the brakes. The airplane immediately shook and several warnings went off in cockpit. According to the tug operator, while at the gate he received brakes released and clear to push from the flight crew, and he proceeded to push the airplane off of the gate and to the area where it was clear to start engines. As they airplane approached the engine start spot, the tug operator stated "cleared to start", and the airplane immediately stopped, and the tug operator saw the airplane nose immediately drop and the nose gear partially collapse. Further inspection revealed the airplane sustained substantial damage to the nose landing gear assembly. ## Factual narrative On May 12, 2014, at about 1737 eastern daylight time (EDT), Delta Airlines flight 1612, a Boeing MD-90, N933DN, experienced a partially collapsed nose gear during pushback from the gate at Boston Logan International Airport (KBOS), Boston, Massachusetts. The passengers and crew exited the aircraft via the jet bridge and there were no injuries. The flight was operating as a 14 Code of Federal Regulations Part 121 regularly scheduled passenger flight between KBOS and Minneapolis-Saint Paul International Airport (KMSP), Minneapolis, Minnesota. According to the flight crew, during pushback they received a new route clearance due to weather along the route. The captain and first officer discussed how they would handle the associated tasks, and agreed they would load the new route and then contact dispatch after the engine start had been accomplished. The crew stated the interphone conversation quality was degraded due to low volume, and there was considerable radio traffic on both clearance delivery and ramp frequencies. As the flight crew finished coordinating tasks, the captain heard on the interphone what he believed was "set brakes" and, because he did not discern any aircraft motion, began to apply the brakes. The airplane immediately shook and several warnings went off in cockpit. According to the tug operator, while at the gate he received brakes released and clear to push from the flight crew, and he proceeded to push the airplane off of the gate and to the area where it was clear to start engines. As they airplane approached the engine start spot, the tug operator stated "cleared to start", and the airplane immediately stopped, and the tug operator saw the airplane nose immediately drop and the nose gear partially collapse. Further inspection revealed the airplane sustained substantial damage to the nose landing gear assembly. ## Aircraft - Registration: [N933DN](https://openairdocs.org/deregistered/N933DN-2020-10-08), registration cancelled 2020-10-08, S/N 53543, built 1997 (OpenAirDocs) - Reported make and model: MCDONNELL DOUGLAS MD90 - 30 (30) - Registry model: [Mcdonnell Douglas MD-90-30](https://openairdocs.org/model/mcdonnell-douglas-md-90-30) (registry code 3023690) (OpenAirDocs) - Registry engine: [IAE V2500SERIES](https://openairdocs.org/engine/iae-v2500series) (registry code 34601, turbo-jet) (OpenAirDocs) - Category: Airplane - Serial number: 53543 - Year built: 1997 - Airframe hours: 31006 - Engines: International Aero Engines V2500 28000 lbs thrust turbo fan; International Aero Engines V2500 28000 lbs thrust turbo fan - Damage: Substantial damage - Flight: Part 121 - Operator: Drelat Air Lines, Inc. - Registered owner: Wells fargo Delaware Trust Co Trustee - Airworthiness certificate: Standard, Transport - Last inspection: Continuous airworthiness, May 12, 2014 - Departed: KBOS, Boston, MA - Destination: MSP, MINNEAPOLIS, MN - Flight plan: IFR - Airport: KBOS, Boston Logan International - Equipment: Electronic multifunction display, Electronic primary flight display, Onboard weather, Stall warning system, Angle of attack indicator, Auto-pilot, Data recorder ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 53; injuries: none; commercial, airline transport; airplane ratings: single-engine sea, multi-engine land; instrument ratings: airplane; medical: class 1, unknown; last flight review October 15, 2013; seat: left; restraint: 5-point; flight hours: 12,066 total, 1,450 in this make and model, 7,934 as pilot in command, 172 in the last 90 days, 3 in the last 24 hours - Co-pilot; age 36; injuries: none; airline transport, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, unknown; last flight review July 19, 2013; seat: right; restraint: 5-point; flight hours: 3,575 total, 773 in this make and model, 221 in the last 90 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 190° at 10 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 75 °F, dew point 48 °F - Altimeter: 29.96 inHg - Observed at: KBOS ## 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 20140512008291A](https://openairdocs.org/incident/20140512008291A), May 12, 2014: Mcdonnell Douglas MD-90-30, Boston, MA, Substantial damage. Delta airlines was being pushed back from the gate. The pilot engaged the brakes and the nose gear collapsed onto the tow bar. ## Docket (1 files) The files NTSB released with the investigation on March 31, 2020, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=89211. 3.7 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 and crew statements (item 1, .PDF, 3.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40481725&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1%20and%20crew%20statements-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.