# NTSB MKC84LA128: Hiller UH-12E, N9740C, Pocahontas, AR, April 24, 1984

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: April 24, 1984, 13:30 local (19:30 UTC)
- Place: Pocahontas, AR
- Coordinates: 36.260837, -90.960327 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=36.2608&lon=-90.9603&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 33671
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=MKC84LA128
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/33671/pdf
- Page: https://openairdocs.org/ntsb/MKC84LA128

## Sequence of events

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

- Loss of engine power(total) - mech failure/malf, maneuvering - aerial application
  - accessory drive assy - failure,partial
  - accessory drive assy - fatigue (cause)
  - engine accessories,engine starter - failure,partial
  - engine accessories,engine starter - fatigue (cause)
  - maintenance,overhaul - improper, other maintenance personnel (cause)
- In flight collision with terrain/water, descent - emergency

## Analysis

THE ACFT CRASHED AFTER AN ENGINE FAILURE DURING A SWATH RUN AT AN ALT OF 20 FT AGL. EXAMINATION OF THE ENGINE REVEALED 3 DOWEL PINS AND 6 SCREWS WHICH HOLD THE STARTER DRIVE GEAR AND THE ACCESSORY DRIVE GEAR HAD SHEARED. METALLURGICAL EXAM REVEALED THAT DOWEL PINS AND SCREWS FAILED FROM FATIGUE. THE ENGINE HAD BEEN IN OPERATION FOR 6 HRS SINCE A MAJOR OVERHAUL.

## Aircraft

- Registration: [N9740C](https://openairdocs.org/deregistered/N9740C-2013-05-24), registration cancelled 2013-05-24, S/N 2118, built 1961 (OpenAirDocs)
- Reported make and model: HILLER UH-12E
- Registry model: [Hiller UH-12E](https://openairdocs.org/model/hiller-uh-12e) (registry code 4360122) (OpenAirDocs)
- Registry engine: [Lycoming 0-540 series](https://openairdocs.org/engine/lycoming-0-540-series) (registry code 41532, reciprocating) (OpenAirDocs)
- Category: Helicopter
- Serial number: 2118
- Airframe hours: 2811
- Engines: LYCOMING VO-540 305 horsepower reciprocating
- Damage: Destroyed
- Flight: Aerial application, Part 137
- Registered owner: Jerry L. Archer
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: Annual, November 13, 1983, 73 hours before
- Departed: POCAHONTAS, AR
- Airport: Helicopter Ag Strip

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 44; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: right; flight hours: 8,050 total, 1 in this make and model

## Weather

- Conditions: Visual (VMC), Day
- Wind: 235° at 10 knots, gusting 12
- Visibility: 20 statute miles
- Lowest ceiling: none
- Temperature: 75 °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 19840424014299A](https://openairdocs.org/incident/19840424014299A), Apr 24, 1984: Hiller UH12E, Pocahontas, AR, Substantial damage. Engine failed. Starter drive and accessory drive gear dowel pins and attach bolts sheared. Recently majored engine.

## Other investigations on N9740C (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 FTW80FPD20](https://openairdocs.org/ntsb/FTW80FPD20), Mar 22, 1980: Hiller UH-12E (N9740C), Mineral Wells, TX, substantial damage

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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