DCA11CA116

NTSB accident investigation · Boeing 737 7H4 · Cape Coral, FL · September 6, 2011

Accident · Serious injuriesData collectionFinal report
Date
September 6, 2011, 12:09 local (17:09 UTC)
Place
Cape Coral, FL
Injuries
1 serious, 141 uninjured
Damage
No damage
Phase of flight
Enroute
Aircraft
N936WNBoeing 737 7H4
Defining event
Enroute-descent: Turbulence encounter
Weather
Visual (VMC) · Day
Status
Completed · report February 23, 2017
Report
Approved by Office Director
NTSB office
Major Investigations Division
Case key
82964

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 the 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 737-7H4: 8 casesAll 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 September 6, 2011, at about 1209 EDT, Southwest Airlines flight 983, a B737-700, N936WN, encountered turbulence enroute from Chicago Midway International Airport (MDW), Chicago, Illinois, to Fort Lauderdale-Hollywood International Airport (FLL), Fort Lauderdale, Florida. Of the five crew members and 137 passengers on board, one flight attendant received seriously injuries. The airplane was not damaged. According to flight crew statements, air traffic control informed them to expect turbulence from thunderstorms in mid to south Florida. In preparation for the possibility of turbulence, the captain called the flight attendants (FA) and advised them to close the galleys and to be seated and that they would likely be able to complete the cabin cleanup after clearing the weather at 10,000 feet. The flight deviated west of the weather and mostly smooth conditions were experienced for about 20 minutes during the descent. As the flight descended below about 14,000 feet, the flight momentarily encountered "large bumps" and two FAs were thrown to the floor after having just gotten out of their jump seats to finish cleaning up the aft galley. As a result, one FA experienced severe pain in her leg and was unable to complete her duties for the remainder of the flight. The captain was immediately informed of the injured FAs condition and medical assistance was requested to meet the airplane at the gate. After an uneventful landing, the FA was transported to the hospital and diagnosed with a broken leg.

Factual narrative

On September 6, 2011, at about 1209 EDT, Southwest Airlines flight 983, a B737-700, N936WN, encountered turbulence enroute from Chicago Midway International Airport (MDW), Chicago, Illinois, to Fort Lauderdale-Hollywood International Airport (FLL), Fort Lauderdale, Florida. Of the five crew members and 137 passengers on board, one flight attendant received serious injuries. The airplane was not damaged. According to flight crew statements, air traffic control informed them to expect turbulence from thunderstorms in mid to south Florida. In preparation for the possibility of turbulence, the captain called the flight attendants (FA) and advised them to close the galleys and to be seated and that they would likely be able to complete the cabin cleanup after clearing the weather at 10,000 feet. The flight deviated west of the weather and mostly smooth conditions were experienced for about 20 minutes during the descent. As the flight descended below about 14,000 feet, the flight momentarily encountered "large bumps" and two FAs were thrown to the floor after having just gotten out of their jump seats to finish cleaning up the aft galley. As a result, one FA experienced severe pain in her leg and was unable to complete her duties for the remainder of the flight. The captain was immediately informed of the injured FAs condition and medical assistance was requested to meet the airplane at the gate. After an uneventful landing, the FA was transported to the hospital and diagnosed with a broken leg.

Aircraft

Registration
N936WN
Reported as
Boeing 737 7H4 (7H4)
Category
Airplane
Serial number
36643
Built
2009
Airframe hours
8,317
Engines
CFM Intl CFM56-7B24/3, 24,000 lbs thrust, turbo fanCFM Intl CFM56-7B24/3, 24,000 lbs thrust, turbo fan
Damage
No damage
Flight
Part 121
Operator
Southwest Airlines
Registered owner
Southwest Airlines Co
Airworthiness certificate
Standard, Transport
Last inspection
Continuous airworthiness · April 25, 2011
Departed
KMDW · Chicago, IL
Destination
KFLL · Fort Lauderdale, FL
Flight plan
IFR
Equipment
Stall warning system, 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
58
Injuries
None
Certificates
Airline transport, Flight instructor
Airplane ratings
Single-engine land, Multi-engine land, Single-engine sea
Instrument ratings
Airplane
Medical
Class 1, Without waivers/limitations
Seat
Left
Restraint
5-point
Flight hours
18,500 total · 12,500 in this make and model · 13,500 as pilot in command · 245 in the last 90 days · 87 in the last 30 days · 7 in the last 24 hours
Role
Co-pilot
Age
38
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
November 7, 2010
Seat
Right
Restraint
5-point
Flight hours
12,852 total · 3,382 in this make and model · 7,506 as pilot in command · 164 in the last 90 days · 46 in the last 30 days · 0 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
230° at 4 knots
Lowest ceiling
5,000 ft broken
Temperature
81 °F, dew point 72 °F
Altimeter
29.89 inHg
Turbulence
Moderate
Observed at
KRSW, 27 nm away

Docket · 1

The files NTSB released with the investigation on February 23, 2017, on NTSB’s docket system: statements, records, photos and specialists’ reports. 498 KB in all.