# NTSB CEN09LA256: Boeing 737-724, N27722, McAllen, TX, April 18, 2009

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Limited investigation · Final report
- Date: April 18, 2009, 01:52 local (06:52 UTC)
- Place: McAllen, TX
- Coordinates: 26.172222, -98.236389 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=26.1722&lon=-98.2364&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Defining event: [Enroute-descent: Turbulence encounter](https://openairdocs.org/ntsb-events/360)
- Highest injury: Serious injuries
- Injuries: 1 serious, 3 minor, 105 uninjured
- Status: Completed, report May 28, 2010
- Report: Approved by Office Director
- NTSB office: Central Region
- Parties: Continental Airlines
- NTSB case key (mKey): 73693
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN09LA256
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/73693/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=73693
- Page: https://openairdocs.org/ntsb/CEN09LA256

## Probable cause

The injured passenger's failure to comply with the requirement to remain seated with a fastened seatbelt.

## Findings

NTSB's coded findings; those marked are part of the probable cause.

- [Turbulence](https://openairdocs.org/ntsb-findings/03032000): Environmental issues › Conditions/weather/phenomena · Compliance w/ procedure; cases with it: [Boeing 737-724, 2 cases](https://openairdocs.org/ntsb-findings/03032000/cases.md?model=13844BY), [All aircraft, 92 cases](https://openairdocs.org/ntsb-findings/03032000/cases.md)
- [Communication (personnel): following instructions](https://openairdocs.org/ntsb-findings/02063537): Personnel issues › Task performance · Passenger (probable cause); cases with it: [Boeing 737-724, 1 case](https://openairdocs.org/ntsb-findings/02063537/cases.md?model=13844BY), [All aircraft, 31 cases](https://openairdocs.org/ntsb-findings/02063537/cases.md)
- [Turbulence](https://openairdocs.org/ntsb-findings/03032000): Environmental issues › Conditions/weather/phenomena · Effect on personnel; cases with it: [Boeing 737-724, 2 cases](https://openairdocs.org/ntsb-findings/03032000/cases.md?model=13844BY), [All aircraft, 92 cases](https://openairdocs.org/ntsb-findings/03032000/cases.md)

## Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event best describes what happened.

- [Enroute-descent: Turbulence encounter](https://openairdocs.org/ntsb-events/360) (defining event); cases with it: [Boeing 737-724, 3 cases](https://openairdocs.org/ntsb-events/360/sequence.md?model=13844BY), [All aircraft, 423 cases](https://openairdocs.org/ntsb-events/360/sequence.md)
- [Enroute-descent: Cabin safety event](https://openairdocs.org/ntsb-events/110); cases with it: [Boeing 737-724, 1 case](https://openairdocs.org/ntsb-events/110/sequence.md?model=13844BY), [All aircraft, 151 cases](https://openairdocs.org/ntsb-events/110/sequence.md)

## Analysis

Before departure the captain briefed all crew members not to perform any services and remain in their jump seats for the duration of the flight due to the possibility of severe weather. The lead flight attendant then made a public address announcement to the passengers that due to possible bad weather there would be no service and the seat belt sign would remain on during the entire flight, stressing the need for the passengers to remain in their seats. In addition, the first officer made a similar announcement to the crew and passengers stressing the need to remain seated for their safety. While descending to the destination airport, a passenger who had gotten up and went into the lavatory sustained serious injuries when the airplane encountered an area of severe turbulence. In addition, two passengers and a flight attendant not wearing their seatbelts sustained minor injuries.

## Factual narrative

On April 18, 2009 at 0152 (Unless otherwise noted, all times in this report are central daylight time based on a 24-hour clock) a Boeing 737-724, N27722 encountered severe turbulence while descending for approach to McAllen Miller International Airport (KMFE). The flight was being operated by Continental Airlines as Flight 511, a Title 14 Code of Federal Regulations (CFR) Part 121 scheduled domestic passenger flight from George Bush Intercontinental/Houston Airport (KIAH), Houston, Texas, to McAllen Miller International Airport (KMFE), McAllen, Texas. The flight was being conducted during night instrument conditions with an active instrument flight rules (IFR) flight plan. A total of 109 people were on board consisting of 2 flight crew, 3 flight attendants, and 104 passengers. One flight attendant sustained minor injuries, 2 passengers sustained minor injuries, and 1 passenger was critically injured. The airplane landed at KMFE at 0216, and arrived at the gate at 0220. In a written report the captain stated that he had briefed all crew members not to perform any services and remain in their jump seats for the duration of the flight due to the possibility of severe weather. The lead flight attendant made a public address announcement to the passengers that due to possible bad weather there would be no service and the seat belt sign would remain on during the entire flight and stressed the need for the passengers to remain in their seats. The flight took off from Houston approximately 3 hours later than scheduled and climbed to 38,000 feet. While en route to KMFE, the pilot had to circumnavigate to avoid thunderstorm cells. The first officer made a similar announcement to the crew and passengers stressing the need to remain seated for their safety. A total of 4 or 5 announcements were made to passengers during the flight to please remain in their seats as several passengers attempted to get up to use the lavatories. The seat belt sign was illuminated for the entire flight. The descent to KMFE began, with the airplane at an airspeed of 280 knots and a descent rate of approximately 1,000 feet per minute. A line of precipitation about 5 to 10 nautical miles wide was indicated on the airplane's weather radar. The depiction was green in color from -2 to +2 degrees. The airplane entered a cloud formation about 20,000 feet mean seal level (MSL) and encountered severe turbulence for about 15 seconds. This included up and down drafts and a roll of about 30 degrees. During the turbulence encounter a passenger, who had gotten up and went into the lavatory, sustained serious injuries. In addition, two passengers and a flight attendant not wearing their seatbelts sustained minor injuries. The descent continued to 10,000 feet MSL as cleared. At that time the lead flight attendant called the captain and notified him of injuries in the aft cabin. The captain continued to the approach and communicating with Air Traffic Control (ATC) the need to land as quickly aspossible for a medical emergency. The flight data recorder was removed and secured for further analysis and the airplane was inspected for damage in accordance with Continental and Boeing maintenance manuals. There was no damage noted and the airplane was released for further flight.

## Aircraft

- Registration: [N27722](https://openairdocs.org/aircraft/N27722), registered now, S/N 28789, built 1999 (OpenAirDocs)
- Reported make and model: BOEING 737-724
- Registry model: [Boeing 737-724](https://openairdocs.org/model/boeing-737-724) (registry code 13844BY) (OpenAirDocs)
- Registry engine: [CFM International CFM56 series](https://openairdocs.org/engine/cfm-international-cfm56-series) (registry code 13802, turbo-fan) (OpenAirDocs)
- Category: Airplane
- Serial number: 28789
- Engines: CFM INTL. CFM56 SERIES 2200 horsepower turbo jet; CFM INTL. CFM56 SERIES 2200 horsepower turbo jet
- Damage: No damage
- Flight: Part 121
- Operator: Continental Airlines Inc, doing business as Continental Airlines
- Registered owner: Continental Airlines Inc
- Airworthiness certificate: Standard, Normal
- Departed: KIAH, Houston, TX
- Destination: KMFE, McAllen, TX
- Flight plan: IFR
- Airport: KMFE, McAllen Miller International

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 49; injuries: none; military, flight engineer, airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review November 9, 2008; seat: left; flight hours: 12,000 total, 6,500 in this make and model, 125 in the last 90 days, 50 in the last 30 days, 8 in the last 24 hours
- Co-pilot; age 36; injuries: none; flight instructor, airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review July 1, 2008; seat: right; flight hours: 6,707 total, 2,417 in this make and model, 2,450 as pilot in command, 217 in the last 90 days, 82 in the last 30 days, 10 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Night
- Wind: 120° at 14 knots
- Visibility: 7 statute miles
- Temperature: 77 °F, dew point 72 °F
- Altimeter: 29.81 inHg
- Observed at: KFME

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 20090418008699A](https://openairdocs.org/incident/20090418008699A), Apr 18, 2009: Boeing 737724, Mc Allen, TX, No damage. Aircraft departed iah enroute to mfe, upon descent into mfe @280 knots and approx 1000 VSI, FL 200 aircraft entered a line of precipitation about 5-10 NM wide,…

## Docket (6 files)

The files NTSB released with the investigation on March 2, 2010, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=73693. 1.0 MB in all.

- Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 264 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40325223&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF
- Flight Attendant Statements (3) (item 2, .PDF, 18 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40325228&FileExtension=.PDF&FileName=Flight%20Attendant%20Statements%20(3)-Redacted.PDF
- Weather Reports and Records (item 3, .PDF, 180 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40325229&FileExtension=.PDF&FileName=Weather%20Reports%20and%20Records-Master.PDF
- Flight Data Recorder Plot (item 4, .PDF, 49 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40325231&FileExtension=.PDF&FileName=Flight%20Data%20Recorder%20Plot-Master.PDF
- Reports from Parties to the Investigation CO QAR report (item 5, .XLS, 493 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40325230&FileExtension=.xls&FileName=Reports%20from%20Parties%20to%20the%20Investigation%20%20CO%20QAR%20report-Master.xls
- Statement of Party Representatives to NTSB Investigation (item 6, .PDF, 41 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40325232&FileExtension=.PDF&FileName=Statement%20of%20Party%20Representatives%20to%20NTSB%20Investigation-Redacted.PDF

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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