DCA14CA093

NTSB accident investigation · Mcdonnell Douglas MD90 - 30 · Boston, MA · May 12, 2014

Accident · No injuriesData collectionFinal report
Date
May 12, 2014, 19:30 local (23:30 UTC)
Place
Boston, MA
Injuries
166 uninjured
Damage
Substantial damage
Phase of flight
Pushback/towing
Aircraft
N933DNMcdonnell Douglas MD90 - 30
Defining event
Pushback/tow-engine not oper: Landing gear collapse
Weather
Visual (VMC) · Day
Status
Completed · report March 30, 2020
Report
Approved by Office Director
NTSB office
Major Investigations Division
FAA report
20140512008291A
Case key
89211

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

On this page

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 · 2

NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.

Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.

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
Reported as
Mcdonnell Douglas MD90 - 30 (30)
Category
Airplane
Serial number
53543
Built
1997
Airframe hours
31,006
Engines
International Aero Engines V2500, 28,000 lbs thrust, turbo fanInternational Aero Engines V2500, 28,000 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

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew · 2

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
53
Injuries
None
Certificates
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
Role
Co-pilot
Age
36
Injuries
None
Certificates
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

Docket · 1

The files NTSB released with the investigation on March 31, 2020, on NTSB’s docket system: statements, records, photos and specialists’ reports. 3.7 MB in all.

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.