# NTSB MKC83LA207: Hiller UH-12E, N173HA, Corwith, IA, August 31, 1983

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: August 31, 1983, 16:45 local (21:45 UTC)
- Place: Corwith, IA
- Coordinates: 42.980072, -93.950325 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=42.9801&lon=-93.9503&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 1 minor
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 33480
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=MKC83LA207
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/33480/pdf
- Page: https://openairdocs.org/ntsb/MKC83LA207

## Sequence of events

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

- Airframe/component/system failure/malfunction, cruise - normal
  - rotor system,main rotor blade cuff - fatigue (cause)
- Forced landing, landing - flare/touchdown
- In flight collision with terrain/water, landing

## Analysis

WHILE EN ROUTE, THE PLT HEARD A CLANKING NOISE BEHIND HIM WHICH WAS FOLLOWED BY A SEVERE VIBRATION OF THE FLT CONTROLS. HE INITIATED AN AUTOROTATIVE DESCENT FROM 3000 FT. HE SAID THE HELICOPTER BEGAN TO ROLL LEFT, THEN RIGHTED ITSELF. THE HELICOPTER TOUCHED DOWN WITH A FORWARD SPEED OF ABOUT 50 MPH, THEN ROLLED & WAS DESTROYED. AN INVESTIGATION REVEALED THAT THE CONTROL ROTOR CUFF, PN 36124-3, HAD FAILED FROM FATIGUE.

## Aircraft

- Registration: [N173HA](https://openairdocs.org/deregistered/N173HA-2018-02-28), registration cancelled 2018-02-28, S/N HA3073, built 1977 (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 VO-540-C2A](https://openairdocs.org/engine/lycoming-vo-540-c2a) (registry code 42244, reciprocating) (OpenAirDocs)
- Category: Helicopter
- Serial number: HA-3073
- Airframe hours: 1410
- Engines: LYCOMING VO-540-B1A 305 horsepower reciprocating
- Damage: Destroyed
- Flight: Ferry, Part 91
- Operator: Benson Flying Service
- Registered owner: Warren A. Jackson
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, May 9, 1983, 300 hours before
- Departed: 1D5, GARNER, IA
- Destination: FONDA, IA

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 36; commercial; airplane ratings: single-engine land; instrument ratings: helicopter; medical: class 2, valid medical--w/ waivers/lim; seat: left; flight hours: 5,623 total, 1,800 in this make and model, 5,471 as pilot in command, 391 in the last 90 days, 8 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 70° at 8 knots
- Visibility: 15 statute miles
- Lowest ceiling: none
- Temperature: 90 °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 19830831045439A](https://openairdocs.org/incident/19830831045439A), Aug 31, 1983: Hiller UH12E, Corwith, IA, Destroyed. Helicopter crashed during autorotation landing after failure in main rotor control system.

## Other investigations on N173HA (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 CHI88DER06](https://openairdocs.org/ntsb/CHI88DER06), Jul 30, 1988: Hiller UH-12E (N173HA), Buffalo Lake, MN, destroyed

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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