# NTSB FTW84LA136: Sikorsky S-58E, N70709, Morgan City, LA, February 13, 1984

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Limited investigation · Final report
- Date: February 13, 1984, 16:30 local (21:30 UTC)
- Place: Morgan City, LA
- Coordinates: 29.729045, -91.129096 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=29.7290&lon=-91.1291&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Serious injuries
- Injuries: 1 serious, 3 minor, 1 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 21259
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW84LA136
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/21259/pdf
- Page: https://openairdocs.org/ntsb/FTW84LA136

## Sequence of events

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

- Airframe/component/system failure/malfunction, hover
  - rotor drive system,intermediate gearbox(42 deg) - fatigue (cause)
- Forced landing, descent - emergency
  - autorotation - performed, pilot in command
- In flight collision with object, landing
  - object - tree(s) (contributing factor)
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

THE HELICOPTER WAS HOVERING ABOVE TREES AT ABOUT 100 FT AGL WHEN THE TAIL ROTOR CHIP DETECTOR LGT FLICKERED SVRL TIMES, THEN ILLUMINATED STEADILY. THIS WAS FOLLOWED BY A LOUD GRINDING NOISE FROM THE TAIL AREA & THE ACFT YAWED TO THE RIGHT. THE ACFT ENTERED AN AUTOROTATION AFTER MAKING 3 TURNS TO THE RIGHT. IT DESCENDED INTO THE TREES AT WHICH TIME THE MAIN ROTOR BLADES WERE BROKEN OFF. AN EXAM OF THE INTERMEDIATE TAIL ROTOR GEAR BOX DISCLOSED THAT 6 TEETH IN THE INPUT BEVEL PINION GEAR, PN S1635-64114, HAD FAILED IN THE ROOT AREA. A METALLURGICAL EXAM DETERMINED THAT THE FAILURE ZONE HAD FATIGUE INDICATIONS. CRACKS WERE FOUND IN OTHER AREAS OF THE GEAR BOX. SIKORSKY ENGINEERS DETERMINED THAT THE GEAR BOX HAD BEEN SUBJECTED TO HEAVY LOADS. THE GEAR BOX HAD BEEN LAST OPENED IN 1968. ONE GEAR WAS NOT A SIKORSKY PRODUCT.

## Aircraft

- Registration: [N70709](https://openairdocs.org/deregistered/N70709-2014-11-13), registration cancelled 2014-11-13, S/N 145693, built 1958 (OpenAirDocs)
- Reported make and model: SIKORSKY S-58E
- Registry model: [Sikorsky H-34J](https://openairdocs.org/model/sikorsky-h-34j) (registry code 8141813) (OpenAirDocs)
- Registry engine: [Wright R-1820 series](https://openairdocs.org/engine/wright-r-1820-series) (registry code 67020, reciprocating) (OpenAirDocs)
- Category: Helicopter
- Serial number: 145693
- Engines: WRIGHT R-1820-84 1525 horsepower reciprocating
- Damage: Substantial damage
- Flight: Aerial observation, Part 91
- Registered owner: John J. Eakin
- Airworthiness certificate: Standard, Utility

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 33; commercial; medical: class 2, valid medical--no waivers/lim.; seat: left; flight hours: 3,124 total, 63 in this make and model, 3,008 as pilot in command, 63 in the last 90 days, 2 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 270° at 6 knots
- Visibility: 20 statute miles
- Lowest ceiling: none
- Temperature: 73 °F

## 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 19840213003279A](https://openairdocs.org/incident/19840213003279A), Feb 13, 1984: Skrsky S58E, Morgan City, LA, Substantial damage. Lost tail rotor drive at hover. Hit trees on autorotation. Tail rotor pinion gear failed. Illegal logging operation

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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