DCA23LA382

NTSB accident investigation · Boeing 737-924ER · Myrtle Beach (Atlantic Ocean) · July 28, 2023

Accident · Serious injuriesClass 4 · LimitedFinal report
Date
July 28, 2023, 08:16 local (12:16 UTC)
Place
Myrtle Beach (Atlantic Ocean)
Injuries
1 serious, 184 uninjured
Damage
No damage
Phase of flight
Enroute
Aircraft
N77431Boeing 737-924ER
Defining event
Enroute-cruise: Turbulence encounter
Weather
Instrument (IMC) · Day
Status
Completed
Report
Approved by Office Director
Investigation class
Class 4 - Basic report with no Prelim publish
NTSB office
Major Investigations Division
Parties
Federal Aviation Administration
Case key
192742

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 convectively induced turbulence (CIT) while in cruise flight.

Findings · 3

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 737-924ER: 2 casesAll aircraft: 145 casesProbable cause
Turbulence: convective turbulenceEnvironmental issues › Conditions/weather/phenomena · Awareness of conditionBoeing 737-924ER: 2 casesAll aircraft: 145 cases

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

United Airlines flight 2122 encountered severe turbulence while in cruise flight at flight level (FL) 330 enroute to Punta Cana Airport (PUJ), Dominican Republic, and a flight attendant (FA) sustained serious injuries. The flight crew reported that after reaching a cruise altitude of FL330 and before entering oceanic airspace they downloaded the latest Weather Services International (WSI) radar image, lightning data, and SkyPath ride reports. The airborne radar was in use which depicted some very small, scattered cells well below their altitude. Shortly thereafter, the captain visually acquired a cloud buildup immediately ahead and below their altitude. With no visual indication of the cloud on the weather radar they made a right turn to avoid any potential turbulence. While in the right turn, the airplane entered visual meteorological conditions and the captain visually acquired another cloud buildup directly ahead. To avoid the buildup the captain continued the right turn to no avail. The airplane entered the clouds and immediately encountered severe turbulence for about 5 seconds. A public address (PA) announcement was immediately made “be seated immediately, be seated immediately”. Following the turbulence encountered the flight crew was notified that two aft FAs had been injured. Just before the turbulence event, the number 2L and 2R FAs had moved the beverage cart to the aft galley, so the 2R FA could use the lavatory. After entering the lavatory, she was thrown into the air and landed on her left ankle and knee. The 2L FA stated that as soon as the 2R FA entered the lavatory, they encountered severe turbulence. She and the beverage cart were tossed into the air, and she impacted the floor of the airplane on her left side. She stated that the impact was like “slamming down from a 5th floor building”. Upon being notified of the injuries, the flight crew declared an emergency and diverted to Myrtle Beach, South Carolina, for medical assistance. The two injured FAs were transported to local hospitals where one was diagnosed with serious injuries. At the time of the turbulence encounter there were no active significant meteorological information (SIGMETs), convective SIGMETs, airman’s meteorological information (AIRMETs), or pilot reports (PIREPs) of any significant turbulence.

Aircraft

Registration
N77431
Reported as
Boeing 737-924ER
Category
Airplane
Serial number
32833
Built
2009
Airframe hours
43,798
Engines
CFM Intl CFM56-7B26/3, 27,300 lbs thrust, turbo fanCFM Intl CFM56-7B26/3, 27,300 lbs thrust, turbo fan
Damage
No damage
Flight
Part 121
Operator
United Airlines Inc
Registered owner
United Airlines Inc
Airworthiness certificate
Standard, Transport
Last inspection
Continuous airworthiness · August 5, 2022
Departed
EWR · Newark, NJ
Destination
PUJ · Punta Cana, OF
Flight plan
IFR
Equipment
Stall warning system, Satellite tracking device, Onboard weather, Electronic primary flight display, Electronic multifunction display, Electronic flight bag or handheld device, Data recorder, Auto-pilot, Angle of attack indicator, ADS-B

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
41
Injuries
None
Certificates
Airline transport, Flight instructor
Airplane ratings
Multi-engine land, Single-engine land
Instrument ratings
Airplane
Medical
Class 1, With waivers/limitations
Last flight review
December 17, 2022
Seat
Left
Restraint
4-point
Flight hours
12,900 total · 6,850 in this make and model · 1,800 as pilot in command · 180 in the last 90 days · 73 in the last 30 days
Role
Co-pilot
Age
35
Injuries
None
Certificate
Airline transport
Airplane ratings
Single-engine land, Multi-engine land
Instrument ratings
Helicopter, Airplane
Medical
Class 1, Without waivers/limitations
Last flight review
March 29, 2023
Seat
Right
Restraint
4-point
Flight hours
4,223 total · 280 in this make and model · 1,298 as pilot in command · 218 in the last 90 days · 99 in the last 30 days · 5 in the last 24 hours

Weather

Conditions
Instrument (IMC) · Day
Turbulence
Severe
Observed at
KMYR
METAR
KMYR 281256Z 00000KT 10SM CLR 29/26 A3017 RMK AO2 SLP216 T02940256

Docket · 3

The files NTSB released with the investigation on November 15, 2023, on NTSB’s docket system: statements, records, photos and specialists’ reports. 2.2 MB in all.