DCA25LA041

NTSB accident investigation · Boeing 757-231 · Cooper Hill, MO · November 18, 2024

Accident · Serious injuriesClass 4 · LimitedFinal report
Date
November 18, 2024, 17:35 local (23:35 UTC)
Place
Cooper Hill, MO
Injuries
1 serious, 106 uninjured
Damage
No damage
Phase of flight
Enroute
Aircraft
N717TWBoeing 757-231
Defining event
Enroute-cruise: Turbulence encounter
Weather
Not reported
Status
Completed
Report
Approved by Office Director
Investigation class
Class 4 - Basic report with no Prelim publish
NTSB office
Major Investigations Division
Parties
FAA, Delta Air Lines
Case key
195519

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 induced turbulence which resulted in a flight attendant serious injury.

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 757-231: 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

Delta Airlines flight 1660, encountered turbulence at an altitude of FL 320 while enroute from Kansas City International Airport (MCI), Kansas City, Missouri, to Hartsfield–Jackson Atlanta International Airport (ATL), Atlanta, Georgia. One flight attendant (FA) sustained a serious injury, and the remaining crewmembers and passengers were uninjured. According to the captain, during the inbound leg to MCI, the flight encountered light turbulence. As a precaution, he instructed the FAs to complete the initial and final announcements simultaneously. That arrival was uneventful. For the outbound leg (MCI–ATL), the captain briefed the FAs to remain seated until he advised them it was safe to begin service. During climbout, the aircraft encountered light turbulence; however, upon reaching cruise altitude above a cloud deck, the flight was smooth. The flight crew reviewed the Flight Weather Viewer – a Delta proprietary app provided to their flight crews to use as a secondary source of weather, which indicated they were exiting the outer edge of an area of convection. No turbulence plots had been issued by Delta for the area, and other aircraft in the area also reported smooth conditions. The National Weather Service (NWS) Aviation Weather Center had issued a Convective Significant Meteorological Information (SIGMET) for an area of thunderstorms moving from 230° at 45 knots with tops to FL420 for the area. The advisory implied the potential for severe turbulence in and near the storms. After confirming smooth conditions, the captain advised the lead FA that cabin service could begin. About five minutes later, while in clear air, the airplane abruptly rolled about 15° to the right. The autopilot corrected the deviation, and the airplane experienced about 3 to 4 seconds of “moderate turbulence” before returning to smooth flight. The captain contacted the cabin to check on the FAs. One FA reported she had struck her head and shoulder but declined immediate medical assistance. The remainder of the flight continued uneventfully, and the airplane landed without further incident in Atlanta. After parking at the gate, the captain again confirmed the condition of the FA. The FA who struck her head stated she was communicating with inflight services and crew tracking regarding her next assignment. The captain provided his contact information for follow-up and reported the incident to the duty pilot. Meteorological reports provided by the airline indicated the flight likely encountered convective turbulence while overflying an area of convection which extended along the general route of flight. Delta issued a turbulence plot about 30 minutes later for the area.

Aircraft

Registration
N717TW
Reported as
Boeing 757-231
Category
Airplane
Serial number
28485
Built
1999
Airframe hours
90,764.24
Engines
P & W PW2037, 37,530 lbs thrust, turbo fanP & W PW2037, 37,530 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 · November 3, 2024
Departed
KMCI · Kansas City, MO
Destination
KATL · Atlanta, GA
Flight plan
IFR
Equipment
Angle of attack indicator, ADS-B, Stall warning system, Onboard weather, Electronic primary flight display, Electronic multifunction display, Electronic flight bag or handheld device, Data recorder, Auto-pilot

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
Certificate
Airline transport
Airplane ratings
Multi-engine land, Single-engine land
Instrument ratings
Airplane
Medical
Class 1
Last flight review
October 15, 2024
Seat
Left
Restraint
Lap only
Flight hours
6,417 total · 6,417 in this make and model · 1,141 as pilot in command · 127 in the last 90 days · 54 in the last 30 days · 4 in the last 24 hours
Role
Co-pilot
Age
36
Injuries
None
Certificate
Airline transport
Airplane ratings
Multi-engine land, Single-engine land
Instrument ratings
Airplane
Medical
Class 1, With waivers/limitations
Last flight review
April 25, 2024
Seat
Right
Restraint
Lap only
Flight hours
4,948 total · 290 in this make and model · 1,051 as pilot in command · 135 in the last 90 days · 80 in the last 30 days · 2 in the last 24 hours

Weather

Conditions
Not reported