# NTSB MKC90LA144: Bell 47D-1, N8117, Fair Oaks, AR, July 12, 1990

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: July 12, 1990, 07:00 local (12:00 UTC)
- Place: Fair Oaks, AR
- Coordinates: 35.22924, -90.779159 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=35.2292&lon=-90.7792&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 1 minor
- Status: Completed, report September 29, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 35013
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=MKC90LA144
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/35013/pdf
- Page: https://openairdocs.org/ntsb/MKC90LA144

## Probable cause

TAIL ROTOR CABLE DISENGAGEMENT DUE TO INADEQUATE MAINTENANCE.

## Sequence of events

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

- Airframe/component/system failure/malfunction, cruise
  - rotorcraft flight control,tail rotor cable - disengaged (cause)
  - maintenance - inadequate, other maintenance personnel (cause)
- In flight collision with terrain/water, descent - uncontrolled
  - aircraft control - not possible, pilot in command

## Analysis

THE COMMERCIAL PLT SAID THAT WHILE CONDUCTING AN AERIAL APPLICATION OPERATION HE FELT A VIBRATION IN THE AIRCRAFT. HE SAID THAT THERE WAS NO LEFT OR RIGHT PEDAL RESPONSE IMMEDIATELY AFTERWARD. HE INITIATED A RIGHT TURN TO RETURN TO THE AIRSTRIP AND THE HELICOPTER WOULD NOT RECOVER. IT CONTINUED TURNING RIGHT AND DESCENDED UNTIL IT COLLIDED WITH THE TERRAIN. POST-ACCIDENT INVESTIGATION REVEALED THE TAIL ROTOR CABLE HAD BECOME DISENGAGED FROM THE TAIL ROTOR PITCH DRUM AND HAD WRAPPED AROUND THE FLANGE OF THE PITCH CHANGE DRUM. THE TAIL ROTOR BLADES WERE LOCKED IN THE RIGHT PEDAL POSITION.

## Aircraft

- Registration: [N8117](https://openairdocs.org/aircraft/N8117), registered now, S/N K732, built 1967 (OpenAirDocs)
- Reported make and model: BELL 47D-1
- Registry model: [Bell 47D1](https://openairdocs.org/model/bell-47d1) (registry code 1180802) (OpenAirDocs)
- Registry engine: [Lycoming VO-435 series](https://openairdocs.org/engine/lycoming-vo-435-series) (registry code 41525, reciprocating) (OpenAirDocs)
- Category: Helicopter
- Serial number: K732
- Engines: LYCOMING VO-435-A1D 260 horsepower reciprocating
- Damage: Substantial damage
- Flight: Aerial application, Part 137
- Registered owner: Taylor Aviation Inc.
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: Annual, June 25, 1990, 43 hours before
- Airport: Hess

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 50; commercial; airplane ratings: single-engine land; medical: class 2, valid medical--w/ waivers/lim; seat: left; flight hours: 35,000 total, 200 in this make and model

## Weather

- Conditions: Visual (VMC), Day
- Wind: 220° at 3 knots
- Visibility: 6 statute miles
- Lowest ceiling: none
- Temperature: 73 °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 19900712025479A](https://openairdocs.org/incident/19900712025479A), Jul 12, 1990: Bell 47D1, Fairoaks, AR, Substantial damage. Lost pedal response on spray run. Made right turn. Unable stop. Impacted. Tail rotor cable broke. Locked right turn

## Other investigations on N8117 (2)

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 FTW91LA091](https://openairdocs.org/ntsb/FTW91LA091), Jun 5, 1991: Bell 47D-1 (N8117), Peach Orchard, AR, substantial damage. Probable cause: THE PILOT'S FAILURE TO MAINTAIN ADEQUATE MAIN ROTOR RPM RESULTING IN DETERIORATED HELICOPTER PERFORMANCE. A FACTOR WAS THE TAILWIND CONDITION.
- [NTSB MKC70DCA14](https://openairdocs.org/ntsb/MKC70DCA14), Jun 7, 1970: Bell 47D1 (N8117), Perry, MO, 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.

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.