DCA19CA091

NTSB accident investigation · Boeing 737 · Franklin, TN · February 18, 2019

Accident · Serious injuriesClass 4 · Data collectionFinal report
Date
February 17, 2019, 18:04 local (Feb 18, 2019, 00:04 UTC)
Place
Franklin, TN
Injuries
1 serious, 1 minor, 143 uninjured
Damage
No damage
Phase of flight
Enroute
Aircraft
N3730BBoeing 737
Defining event
Enroute-descent: Turbulence encounter
Weather
Instrument (IMC) · Night
Status
Completed
Report
Approved by Office Director
Investigation class
Class 4 - Basic report with no Prelim publish
NTSB office
Major Investigations Division
Case key
99058

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

an encounter with convective turbulence during descent.

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.

Turbulence: convective turbulenceEnvironmental issues › Conditions/weather/phenomena · Effect on personnelBoeing 737-832: 1 caseAll aircraft: 145 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 February 17, 2019, about 1804 central standard time, Delta Air Lines flight 957, a Boeing 737-800, N3730B, encountered turbulence during descent into Atlanta Hartsfield-Jackson International Airport (KATL), Atlanta, Georgia. Of the 145 passengers and crew onboard, one flight attendant sustained serious injuries and one received minor injuries. The airplane was not damaged. The flight was operating under 14 Code of Federal Regulations Part 121 as a regularly scheduled passenger flight from Bozeman Yellowstone International Airport (KBZN), Bozeman, Montana, to KATL. According to the flight crew, air traffic control informed them to expect light and occasional moderate turbulence during the descent. About 10 minutes before beginning their descent, the flight crew illuminated the seat belt sign and instructed the flight attendants (FA) to stow the carts and take their seats. Shortly after departing FL350 for FL250, and the airplane encountered two “rapid-bumps of light-moderate turbulence” at approximately FL345. The flight crew slowed the airplane and contacted the FAs and was informed that the aft FA was injured. According to the flight attendants, the flight had been routine, having experienced only occasional light turbulence. The two aft FAs had finished their meal service and secured the galley. The two FAs were making their final walkthrough of the cabin when the captain made the public address announcement to discontinue cabin service, when the turbulence was encountered. The two aft FAs reported they were thrown up to the ceiling and then came “crashing back down” onto the galley floor. One of the FAs was in intense pain after striking the floor hard and was attended to by two medically qualified passengers. The FA was moved to an empty passenger row for landing and was provided oxygen and pain medication. The flight crew declared an emergency and requested paramedics meet the flight at the gate. The FA was transported to the hospital where she was diagnosed with a fractured vertebra. Post accident examination of the weather data determined that the accident flight was in instrument meteorological conditions (IMC) in an area of convectively induced turbulence due to embedded rain shower activity when the turbulence was encountered. While there was no lightning activity around the accident site at the accident time, there were pockets of strong rain shower cells within the complex of precipitation as a whole. The area where the accident occurred was covered by AIRMET Tango that warned of moderate turbulence conditions.

Aircraft

Registration
N3730B
Reported as
Boeing 737 (832)
Category
Airplane
Serial number
30538
Built
2000
Airframe hours
54,653
Engines
CFM CFM56-7B26, 26,300 lbs thrust, turbo fanCFM CFM56-7B26, 26,300 lbs thrust, turbo fan
Damage
No damage
Flight
Part 121
Operator
Delta Air Lines Inc
Registered owner
Delta Air Lines Inc
Airworthiness certificate
Standard, Transport
Last inspection
Continuous airworthiness · February 16, 2019
Departed
KBZN · Bozeman, MT
Destination
KATL · Atlanta, GA
Flight plan
IFR
Equipment
Stall warning system, Onboard weather, Heads up display, ADS-B, Electronic primary flight display, Electronic multifunction display, Electronic flight bag or handheld device, Data recorder, Auto-pilot, Angle of attack indicator

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 · 6

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
63
Injuries
None
Certificate
Airline transport
Airplane ratings
Single-engine land, Multi-engine land
Instrument ratings
Airplane
Medical
Class 1, With waivers/limitations
Last flight review
September 15, 2018
Seat
Left
Flight hours
16,098 total · 6,637 in this make and model · 4,161 as pilot in command · 186 in the last 90 days · 5 in the last 24 hours
Role
Co-pilot
Age
38
Injuries
None
Certificate
Airline transport
Airplane ratings
Single-engine land, Multi-engine land
Instrument ratings
Airplane
Medical
Class 1, With waivers/limitations
Last flight review
January 7, 2019
Seat
Right
Flight hours
1,308 total · 83 in this make and model · 97 in the last 90 days · 2 in the last 24 hours
Role
Cabin crew
Injuries
None
Medical
Unknown
Seat
None
Restraint
None
Flight hours
0 total · 0 in this make and model
Role
Cabin crew
Injuries
None
Medical
Unknown
Seat
None
Restraint
None
Flight hours
0 total · 0 in this make and model
Role
Cabin crew
Injuries
Minor
Medical
Unknown
Seat
None
Restraint
None
Flight hours
0 total · 0 in this make and model
Role
Cabin crew
Injuries
Serious
Medical
Unknown
Seat
None
Restraint
None
Flight hours
0 total · 0 in this make and model

Weather

Conditions
Instrument (IMC) · Night
Wind
100° at 6 knots
Visibility
0.25 statute miles
Temperature
48 °F, dew point 48 °F
Altimeter
29.86 inHg
Icing
Unknown
Observed at
KATL, 184 nm away

Docket · 19

The files NTSB released with the investigation on July 13, 2021, on NTSB’s docket system: statements, records, photos and specialists’ reports. 330 MB in all.

Pilot/operator aircraft accident report, NTSB form 6120.1Item 1 · PDF · 11 pages · 487 KBWeather study reportItem 2 · PDF · 30 pages · 2.0 MBWeather attachment 1Item 3 · GIF · 3.5 MBWeather attachment 2Item 4 · GIF · 12.5 MBWeather attachment 3Item 5 · GIF · 9.7 MBWeather attachment 4Item 6 · PDF · 5 pages · 2.6 MBWeather attachment 5Item 7 · PDF · 15 pages · 506 KBWeather attachment 6Item 8 · ZIP · 294 MBOperational factors specialists reportItem 9 · PDF · 41 pages · 1.4 MBOperational factors - attachment 1 - crew statementsItem 10 · PDF · 8 pages · 342 KBOperational factors - attachment 2 - flight crew training records [excerpts]Item 11 · PDF · 4 pages · 124 KBOperational factors - attachment 3 - accident flight weight data recordsItem 12 · PDF · 7 pages · 66 KBOperational factors - attachment 4 - accident flight releaseItem 13 · PDF · 30 pages · 113 KBOperational factors - attachment 5 - acars message [excerpts]Item 14 · PDF · 3 pages · 63 KBOperational factors - attachment 6 - archived pirepsItem 15 · CSV · 55 KBOperational factors - attachment 7 - delta air lines airway manual [excerpts]Item 16 · PDF · 7 pages · 174 KBOperational factors - attachment 8 - delta air lines flight operations manual [excerpts]Item 17 · PDF · 10 pages · 315 KBOperational factors - attachment 9 - delta air lines operations manual [excerpts]Item 18 · PDF · 10 pages · 280 KBOperational factors - attachment 10 - delta air lines on-board manual [excerpts]Item 19 · PDF · 7 pages · 1.9 MB

Other investigations on N3730B · 1

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