# NTSB CHI91LA205: Hiller UH-12D, N94515, Savoy, IL, July 2, 1991

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: July 2, 1991, 12:00 local (17:00 UTC)
- Place: Savoy, IL
- Coordinates: 40.059837, -88.250869 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=40.0598&lon=-88.2509&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report March 24, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 15111
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI91LA205
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/15111/pdf
- Page: https://openairdocs.org/ntsb/CHI91LA205

## Probable cause

THE PILOT'S FAILURE TO MAINTAIN TAIL ROTOR CLEARANCE FROM THE GROUND.  A RELATED FACTOR IS THE PILOT'S LACK OF TOTAL EXPERIENCE IN HELICOPTERS.

## Sequence of events

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

- In flight collision with terrain/water, maneuvering
  - lack of total experience in type of aircraft, pilot in command (contributing factor)
  - clearance - misjudged, pilot in command (cause)
- Hard landing, landing
  - terrain condition - grass

## Analysis

THE COMMERCIAL AIRPLANE PILOT WAS PERFORMING 'QUICK STOP' MANEUVERS WHILE PRACTICING FOR HIS HELICOPTER RATING.  HE REPORTED THAT HE ENTERED THE MANEUVER AT 20 FEET ABOVE THE GROUND, THEN MADE SEVERAL ADJUSTMENTS WITH BOTH CYCLIC AND COLLECTIVE IN AN ATTEMPT TO MAINTAIN ROTOR RPM AND ALTITUDE.  THE HELICOPTER DESCENDED DURING THE MANEUVER AND THE TAIL ROTOR STRUCK THE GROUND.  THE PILOT STATED THAT HE BEGAN TO LOSE DIRECTIONAL CONTROL AFTER THE TAIL ROTOR GROUND CONTACT, SO HE REDUCED COLLECTIVE AND MADE A HARD LANDING ON THE GRASS ADJACENT TO THE RUNWAY.

## Aircraft

- Registration: [N94515](https://openairdocs.org/aircraft/N94515), registered now, S/N 1172 (OpenAirDocs)
- Reported make and model: HILLER UH-12D
- Registry model: [Hiller UH-12D](https://openairdocs.org/model/hiller-uh-12d) (registry code 4360118) (OpenAirDocs)
- Registry engine: [Lycoming VO-435 series](https://openairdocs.org/engine/lycoming-vo-435-series) (registry code 41525, reciprocating) (OpenAirDocs)
- Category: Helicopter
- Serial number: 1172
- Airframe hours: 7124
- Engines: LYCOMING V0-435-23C-8 260 horsepower reciprocating
- Damage: Substantial damage
- Flight: Instructional, Part 91
- Operator: Board Of Trustees-U. Of I.
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, June 28, 1991, 4 hours before
- Airport: CMI, Champaign-Willard

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 25; flight instructor, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: center; flight hours: 360 total, 42 in this make and model, 276 as pilot in command, 48 in the last 90 days, 15 in the last 30 days, 2 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 250° at 5 knots
- Visibility: 20 statute miles
- Lowest ceiling: none
- Temperature: 88 °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 19910702025679A](https://openairdocs.org/incident/19910702025679A), Jul 2, 1991: Hiller UH12D, Champaign-Urban, IL, Substantial damage. Practicing quick stop maneuver. Tail rotor hit ground. Lost directional control. Set down hard to avoid spin.

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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