# NTSB CHI84LA181: Bell 47D-1, N13012, Ridge Farm, IL, May 6, 1984

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: May 5, 1984, 20:02 local (May 6, 1984, 01:02 UTC)
- Place: Ridge Farm, IL
- Coordinates: 39.889232, -87.650238 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=39.8892&lon=-87.6502&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 12603
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI84LA181
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/12603/pdf
- Page: https://openairdocs.org/ntsb/CHI84LA181

## Sequence of events

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

- Loss of engine power(partial) - nonmechanical, takeoff - initial climb
  - adequate rotor rpm - not maintained, pilot in command (cause)
- Forced landing, descent - emergency
  - autorotation - performed, pilot in command
- Other gear collapsed, landing - flare/touchdown
  - landing gear,skid assembly - overload
  - flare - not possible, pilot in command
- Roll over, landing

## Analysis

THE HELICOPTER ROLLED OVER AFTER A HARD LANDING FOLLOWING LOSS OF ROTOR RPM. THE PLT REPORTED THAT DURING INITIAL CLIMB AT ABOUT 300 FT AGL THE ROTOR DECREASED ABOUT 500 RPM. HE TRIED TO REGAIN ROTOR RPM UNTIL ABOUT 100 FT AGL AND THEN TRIED AN AUTOROTATION. UPON LANDING THE ACFT ROLLED OVER. POST ACCIDENT INVESTIGATION REVEALED NO MECHANICAL DISCREPENCIES WITH THE ACFT.

## Aircraft

- Registration: [N13012](https://openairdocs.org/deregistered/N13012-2018-02-08), registration cancelled 2018-02-08, S/N 648, built 1953 (OpenAirDocs)
- Reported make and model: BELL 47D-1
- Registry model: [Bell 47D1](https://openairdocs.org/model/bell-47d1) (registry code 1180802) (OpenAirDocs)
- Registry engine: [Franklin 6V4 series](https://openairdocs.org/engine/franklin-6v4-series) (registry code 27033, reciprocating) (OpenAirDocs)
- Category: Helicopter
- Serial number: 648
- Airframe hours: 2264
- Engines: FRANKLIN 6 VS-335-A 225 horsepower reciprocating
- Damage: Substantial damage
- Flight: Aerial application, Part 137
- Operator: Ag Air, Inc.
- Registered owner: Illiana Helicopter Service Inc
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: Annual, May 31, 1985, 74 hours before

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 27; flight instructor, commercial; airplane ratings: single-engine land, single-engine sea, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: left; flight hours: 1,751 total, 313 in this make and model, 1,511 as pilot in command, 6 in the last 90 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 12 statute miles
- Lowest ceiling: 15,000 ft overcast
- Temperature: 63 °F, dew point 41 °F
- Altimeter: 29.00 inHg
- Observed at: CMI, 25 nm away

## 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 19840505017089A](https://openairdocs.org/incident/19840505017089A), May 5, 1984: Bell 47D1, Ridge Farm, IL, Substantial damage. Lost engine and rotor RPM after takeoff. Made a hard autorotation landing and rolled over. No engine defects found.

## Other investigations on N13012 (3)

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 FTW98LA144](https://openairdocs.org/ntsb/FTW98LA144), Mar 11, 1998: Bell 47D1 (N13012), Jeanerette, LA, substantial damage. Probable cause: The in-flight disconnect of the rotating scissors due to the separation of its hinge bolt.
- [NTSB FTW75DPG02](https://openairdocs.org/ntsb/FTW75DPG02), Jul 6, 1974: Bell 47D-1 (N13012), Almyra, AR, substantial damage
- [NTSB NYCA3FKM14](https://openairdocs.org/ntsb/NYCA3FKM14), Oct 6, 1972: Bell 47D1 (N13012), Charlotte, NC, 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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