# NTSB ATL88LA030: Hiller UH-12B, N922TE, Newnan, GA, November 7, 1987

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: November 7, 1987, 13:30 local (18:30 UTC)
- Place: Newnan, GA
- Location: 33.3758° N, 84.7773° W: Placed by OpenAirDocs: center of Newnan, GA, within about 6 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=33.3758&lon=-84.7773&mi=10
- Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed, report February 14, 1989
- Report: Approved by Office Director
- NTSB case key (mKey): 7671
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ATL88LA030
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/7671/pdf
- Page: https://openairdocs.org/ntsb/ATL88LA030

## Sequence of events

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

- Airframe/component/system failure/malfunction, approach - vfr pattern - final approach
  - rotor drive system,tail rotor gearbox(90 deg) - vibration (cause)
  - rotor drive system,tail rotor gearbox(90 deg) - fatigue (cause)
  - rotor drive system,tail rotor gearbox(90 deg) - separation (cause)
  - autorotation - performed, pilot in command
- Roll over, landing
  - directional control - reduced

## Analysis

THE TAIL ROTOR 90 DEGREE GEARBOX MOUNTING FLANGE FRACTURED DURING APCH TO LAND, WHILE THE HELICOPTER WAS AT ABOUT 75 FT AGL. THE GEARBOX SUBSEQUENTLY SEPARATED FROM THE HELICOPTER. THE PLT INITIATED AN AUTOROTATION. THE HELICOPTER ROLLED OVER ON LDG. METALLURGICAL ANALYSIS INDICATED THAT THE FLANGE FAILED AS A RESULT OF EXTENSIVE PREEXISTENT FATIGUE CRACKING, AND THAT THE CRACKING WAS THE RESULT OF EXCESSIVE VIBRATION.

## Aircraft

- Registration: [N922TE](https://openairdocs.org/deregistered/N922TE-2020-01-28), registration cancelled 2020-01-28, S/N 714 (OpenAirDocs)
- Reported make and model: HILLER UH-12B
- Registry model: [Hiller UH-12B](https://openairdocs.org/model/hiller-uh-12b) (registry code 4360110) (OpenAirDocs)
- Category: Helicopter
- Serial number: 714
- Engines: FRANKLIN 6V-335-B 210 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Unlimited Directions,Inc.
- Registered owner: Unlimited Directions, Inc
- Departed: CARROLLTON, GA

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 39; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: center; flight hours: 3,141 total, 28 in this make and model, 43 in the last 90 days, 2 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Lowest ceiling: none

## 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 19871107067439A](https://openairdocs.org/incident/19871107067439A), Nov 7, 1987: Hiller UH12B, Newnan, GA, Substantial damage. PIC lost tail rotor control on approach. Initiated autorotation but plane rolled over on impact. Gear box separated.

## Other investigations on N922TE (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 ATL83FA261](https://openairdocs.org/ntsb/ATL83FA261), Jul 9, 1983: Hiller UH-12B (N922TE), Huntsville, AL, 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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