DCA16CA207

NTSB accident investigation · Boeing 737 3H4 · Baltimore, MD · August 5, 2016

Accident · No injuriesData collectionFinal report
Date
August 4, 2016, 21:02 local (Aug 5, 2016, 01:02 UTC)
Place
Baltimore, MD
Injuries
134 uninjured
Damage
Substantial damage
Phase of flight
Pushback/towing
Aircraft
N368SWBoeing 737 3H4
Defining event
Pushback/towing: Ground handling event
Weather
Visual (VMC) · Night
Status
Completed · report January 23, 2017
Report
Approved by Office Director
NTSB office
Major Investigations Division
FAA report
20160804013139A
Case key
93766

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 tug operators excessive speed during pushback.

Findings · 1

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.

Towing and taxiing: towingAircraft › Aircraft handling/service · Incorrect use/operationBoeing 737-3H4: 1 caseAll aircraft: 10 casesProbable cause

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 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
Reported as
Boeing 737 3H4 (3H4)
Category
Airplane
Serial number
26579
Built
1993
Airframe hours
72,354
Engines
CFM Intl. CFM56 SERIES, turbo fanCFM 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

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
51
Injuries
None
Certificate
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
Role
Co-pilot
Age
45
Injuries
None
Certificate
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

Docket · 7

The files NTSB released with the investigation on January 25, 2017, on NTSB’s docket system: statements, records, photos and specialists’ reports. 6.9 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.

Other investigations on N368SW · 1

Matched to the same aircraft by N-number and date.