# NTSB ATL88FA213: Bell TH-1L, N465JR, Walterboro, SC, July 12, 1988

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Field investigation · Final report
- Date: July 12, 1988, 07:30 local (11:30 UTC)
- Place: Walterboro, SC
- Coordinates: 32.899494, -80.669235 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=32.8995&lon=-80.6692&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Serious injuries
- Injuries: 1 serious
- Status: Completed, report October 6, 1989
- Report: Approved by Office Director
- NTSB case key (mKey): 7616
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ATL88FA213
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/7616/pdf
- Page: https://openairdocs.org/ntsb/ATL88FA213

## 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)
  - rotor drive system,intermediate gearbox(42 deg) - failure,total (cause)
  - acft/equip,inadequate design, manufacturer (contributing factor)
  - inadequate certification/approval,aircraft, faa(organization) (contributing factor)
- Loss of control - in flight, hover
  - directional control - not possible
- In flight collision with terrain/water, descent - emergency
  - autorotation - attempted
  - object - tree(s) (contributing factor)

## Analysis

THE MILITARY SURPLUS HELICOPTER EXPERIENCED A 42 DEGREE GEAR BOX FAILURE WHILE LIFTING A LOAD OF LOGS. THE HELICOPTER SUBSEQUENTLY LANDED HARD AS THE PLT WAS ATTEMPTING TO AUTOROTATE TO A LDG. METALLURGICAL EXAMINATION OF THE GEARBOX REVEALED THAT A GEAR TOOTH ON THE INPUT QUILL PINION HAD FAILED DUE TO FATIGUE. NO EVIDENCE OF PREEXISTING DAMAGE OR IMPROPER OVERHAUL PROCEDURES WAS FOUND. THE GEARBOX TSO WAS ABOUT 440 HRS. THE 42 DEG GEAR BOX MAY BE OVER- HAULED ON CONDITION. INVESTIGATION REVEALED THAT THE HELICOPTER HAD EXPERIENCED IN EXCESS OF 13,000 LIFT CYCLES IN 380 HRS SINCE IT WAS PLACED IN SERVICE IN A LOGGING OPERATION. THE HELICOPTER HAD BEEN FAA-CERTIFICATED IN THE RESTRICTED CATEGORY FOR EXTERNAL LOAD OPERATIONS; HOWEVER, BELL RPTS THAT THE ACFT WAS NOT DESIGNED FOR REPEATED HEAVY LIFTING. THERE HAVE BEEN AT LEAST 2 OTHER SIMILAR FAILURES INVOLVING SURPLUS UH-1/TH-1 HELICOPTERS USED IN LOGGING OPERATIONS. THE LANDING SITE WAS STREWN WITH CUT TIMBER AND SMALL TREES.

## Aircraft

- Registration: [N465JR](https://openairdocs.org/deregistered/N465JR-2018-01-23), registration cancelled 2018-01-23, S/N 157828 (OpenAirDocs)
- Reported make and model: BELL TH-1L
- Registry model: [Bell TH-1L](https://openairdocs.org/model/bell-th-1l) (registry code 1180817) (OpenAirDocs)
- Registry engine: [Lycoming T53-L-13](https://openairdocs.org/engine/lycoming-t53-l-13) (registry code 41551, turbo-shaft) (OpenAirDocs)
- Category: Helicopter
- Serial number: 157828
- Airframe hours: 7676
- Engines: LYCOMING T53-L13BA 1400 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Other work use, Part 133
- Operator: S. Eastern Helicopter Logging
- Registered owner: Moore, W Marvin
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: 100 hour, May 14, 1988, 131 hours before

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 42; commercial, flight instructor, airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane, helicopter; medical: class 2, valid medical--no waivers/lim.; seat: left; flight hours: 7,334 total, 3,900 in this make and model, 5,500 as pilot in command, 212 in the last 90 days, 82 in the last 30 days, 6 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 5 statute miles
- Lowest ceiling: none
- Temperature: 70 °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 19880712026399A](https://openairdocs.org/incident/19880712026399A), Jul 12, 1988: Bell TH13T, Walterboro, SC, Substantial damage. Vibration on sling load dropped load spin right to crash. Tail rotor gear box failed.

## Other investigations on N465JR (1)

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.

- [NTSB SEA97LA025](https://openairdocs.org/ntsb/SEA97LA025), Nov 5, 1996: Garlick TH-1L (N465JR), Leavenworth, WA, destroyed, 1 fatal. Probable cause: Fatigue failure of the vertical stabilizer spar cap and subsequent loss of the rotorcraft's vertical stabilizer. Factors include inadequate inspection or trouble-shooting of the aircraft tail cone…

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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