# NTSB FTW91FA070: Bell 206B, N213AL, So. Marsh 275, April 23, 1991

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Field investigation · Final report
- Date: April 23, 1991, 07:45 local (12:45 UTC)
- Place: So. Marsh 275
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 2 fatal
- Status: Completed, report January 25, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 23255
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW91FA070
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/23255/pdf
- Page: https://openairdocs.org/ntsb/FTW91FA070

## Probable cause

THE INFLIGHT STRUCTURAL FAILURE AND SEPARATION OF THE VERTICAL FIN WHICH LED TO A LOSS OF CONTROL AND MAST BUMPING. THE FAILURE OF THE FIN WAS DUE TO INADEQUATE CORROSION CONTROL EFFORTS BY THE OPERATOR.

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Airframe/component/system failure/malfunction, cruise
  - vertical stabilizer attachment - failure,total (cause)
  - maintenance,inspection - inadequate, company maintenance personnel (cause)
  - vertical stabilizer attachment - fatigue (cause)
  - vertical stabilizer attachment - corroded (cause)
- Loss of control - in flight, cruise
  - remedial action - not possible, pilot in command
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

THE PILOT DID NOT MAKE THE REQUIRED 15 MINUTE RADIO CHECK AFTER DEPARTURE FROM AN OFFSHORE RIG AND A RADIO AND AIR SEARCH WAS INITIATED. ABOUT TWO HOURS LATER, DEBRIS WAS FOUND FLOATING ABOUT THREE MILES FROM THE DEPARTURE POINT. RECOVERED DEBRIS INDICATED THAT THE AIRCRAFT HAD EXPERIENCED AN INFLIGHT SEPARATION OF THE VERTICAL FIN AND SUBSEQUENT MAST BUMPING. METALLURGICAL EXAMINATION OF THE VERTICAL FIN ATTACHMENT FITTINGS REVEALED THAT THEY HAD SEPARATED DUE TO FATIGUE INDUCED BY CORROSION AND CORROSION PITTING. THE EXAMINATION ALSO REVEALED THAT THE OPERATOR HAD UNSUCCESSFULLY ATTEMPTED TO COMBAT THE CORROSION DURING A REFURBISHMENT OF THE AIRFRAME. ALL OF THE FATIGUE FRACTURES APPEARED OLD AND ONE HAD PAINT IN THE FRACTURE.

## Aircraft

- Registration: [N213AL](https://openairdocs.org/deregistered/N213AL-1997-12-13), registration cancelled 1997-12-13, S/N 1066 (OpenAirDocs)
- Reported make and model: BELL 206B
- Registry model: [Bell 206B](https://openairdocs.org/model/bell-206b) (registry code 1181511) (OpenAirDocs)
- Category: Helicopter
- Serial number: 1066
- Airframe hours: 11375
- Engines: ALLISON 250-C20 400 horsepower turbo shaft
- Damage: Destroyed
- Flight: Part 135
- Operator: Offshore Logistics, Inc., doing business as Air Logistics
- Airworthiness certificate: Standard, Normal
- Last inspection: AAIP, March 2, 1991, 74 hours before
- Departed: NONE, S. MARSH 261, GM
- Destination: NONE, EWING BANKS 947, GM
- Flight plan: Company VFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 43; airline transport, commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: helicopter, airplane; medical: class 1, valid medical--w/ waivers/lim; seat: right; toxicology performed; flight hours: 3,971 total, 265 in this make and model, 1,883 as pilot in command, 81 in the last 90 days, 70 in the last 30 days, 2 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 10° at 10 knots
- Visibility: 7 statute miles
- Lowest ceiling: 2,000 ft overcast
- Temperature: 73 °F, dew point 72 °F
- Altimeter: 29.00 inHg

## 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 19910423015959A](https://openairdocs.org/incident/19910423015959A), Apr 23, 1991: Bell 206B, S Marsh 275, LA, Destroyed, 2 fatal. Tail rotor fin fittings failed due to fatigue. Helicopter crashed and sank in gulf.

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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