# NTSB FTW89FA013: Aerospatiale AS-355F-1, N355EH, W. Cameron 617, November 4, 1988

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Field investigation · Final report
- Date: November 4, 1988, 06:51 local (12:51 UTC)
- Place: W. Cameron 617
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 4 fatal, 2 serious
- Status: Completed, report June 25, 1990
- Report: Approved by Office Director
- Safety recommendations: Yes
- NTSB case key (mKey): 22751
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW89FA013
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/22751/pdf
- Page: https://openairdocs.org/ntsb/FTW89FA013

## Probable cause

THE LOSS OF CONTROL OF THE AIRCRAFT WHICH OCCURRED WHEN THE TAIL ROTOR DRIVE SHAFT EXPERIENCED A FATIGUE INDUCED MATERIAL FAILURE AND TAIL ROTOR THRUST WAS LOST. EVIDENCE INDICATED THAT THE SHAFT WAS UNDER DESIGNED FOR THE LOADS THAT WERE ENCOUNTERED DURING NORMAL OPERATIONS.

## Sequence of events

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

- Airframe/component/system failure/malfunction, takeoff - initial climb
  - rotor drive system,tail rotor drive shaft - separation (cause)
  - acft/equip,inadequate design, manufacturer (cause)
  - rotor drive system,tail rotor drive shaft - fatigue (cause)
- Loss of control - in flight, takeoff - initial climb
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

ACFT WAS DEPARTING AN ELEVATED HELIDECK ON AN OFFSHORE PRODUCTION PLATFORM WHEN IT EXPERIENCED A COMPLETE LOSS OF TAIL ROTOR THRUST AND ACFT CONTROL DUE TO A FAILURE OF THE TAIL ROTOR DRIVE SHAFT. THE FAILURE OCCURRED AS THE PLT INITIATED HIS TAKEOFF WITH THE ACFT HAVING JUST CLEARED THE DECK AND RECOVERY WAS NOT POSSIBLE. INVESTIGATION REVEALED THAT THE DRIVE SHAFT HAD FAILED AS A RESULT OF FATIGUE CRACKING IN AN AREA OF FRETTING WHERE THE SHAFT WAS BONDED AND BOLTED TO ITS COUPLING. THIS AND PREVIOUS FAILURES IN THE SAME AREA INDICATED THAT THE SHAFT WAS UNDER DESIGNED FOR THE APPLICATION AND NORMAL OPERATING STRESSES. SHAFT WAS SUBSEQUENTLY RE-DESIGNED AND THE FLEET RETROFITTED.

## Aircraft

- Registration: [N355EH](https://openairdocs.org/deregistered/N355EH-1991-12-23), registration cancelled 1991-12-23, S/N 5137 (OpenAirDocs)
- Reported make and model: AEROSPATIALE AS-355F-1
- Registry model: [Aerospatiale AS 355 F ECUREUIL](https://openairdocs.org/model/aerospatiale-as-355-f-ecureuil) (registry code 8680806) (OpenAirDocs)
- Category: Helicopter
- Serial number: 5137
- Airframe hours: 8747
- Engines: ALLISON 250-C20F 425 horsepower turbo shaft
- Damage: Destroyed
- Flight: Part 135
- Registered owner: Era Helicopters
- Airworthiness certificate: Standard, Normal; Standard, Utility
- Last inspection: AAIP, November 3, 1988
- Departed: NONE, W. CAMERON 617, GM
- Flight plan: Company VFR
- Airport: WC61, W. Cameron 617

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 43; airline transport; instrument ratings: helicopter; medical: class 1, valid medical--w/ waivers/lim; seat: right; toxicology performed; flight hours: 8,819 total, 1,081 in this make and model, 8,162 as pilot in command, 270 in the last 90 days, 81 in the last 30 days, 6 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 180° at 25 knots, gusting 35
- Visibility: 10 statute miles
- Lowest ceiling: 1,500 ft broken
- Altimeter: 29.00 inHg
- Observed at: C556, 15 nm away

## 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 19881104049389A](https://openairdocs.org/incident/19881104049389A), Nov 4, 1988: Aerosp AS355F, West Cameron, LA, Destroyed, 4 fatal. Tail rotor drive shaft snapped at takeoff hover. Loss control,spun into water at high impact.

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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