# NTSB MIA89LA165: Bell 47G-3B-1, N53SP, Keystone Hgts., FL, May 30, 1989

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: May 30, 1989, 08:45 local (12:45 UTC)
- Place: Keystone Hgts., FL
- Coordinates: 29.780031, -82.029174 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=29.7800&lon=-82.0292&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 1 minor
- Status: Completed, report July 9, 1990
- Report: Approved by Office Director
- NTSB case key (mKey): 32443
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=MIA89LA165
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/32443/pdf
- Page: https://openairdocs.org/ntsb/MIA89LA165

## Probable cause

THE TAIL ROTOR DRIVE SYSTEM BECAME DISCONNECTED DUE TO A BENT TAIL ROTOR DRIVE SHAFT.  THE TREES CONTRIBUTED TO THE HELICOPTER DAMAGE.

## 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 drive system,tail rotor drive shaft - bent (cause)
  - rotor drive system,tail rotor drive shaft - disconnected (cause)
- Forced landing, descent - emergency
  - autorotation
- In flight collision with object, landing - flare/touchdown
  - object - tree(s) (contributing factor)

## Analysis

THE PLT RPRTD THAT WHILE DEPG ON A SPRAYING OPN, THE HELICOPTER YAWED TO THE RGT & LEFT PEDAL APPLICATION WOULD NOT CORRECT THE YAW. HE THEN PERFORMED AN AUTOROTATIVE LANDING, SUBSEQUENTLY PULLING THE COLLECTIVE TO CUSHION IMPACT WITH TREES. A POST-ACDNT EXAM OF THE HELICOPTER REVEALED THE TAIL ROTOR DRIVE SHAFT HAD BECOME BENT BETWEEN THE #1 & #2 BEARINGS, ALLOWING THE FWD SHAFT TO PULL FROM THE COUPLING.

## Aircraft

- Registration: [N53SP](https://openairdocs.org/deregistered/N53SP-2001-08-10), registration cancelled 2001-08-10, S/N 67-17111 (OpenAirDocs)
- Reported make and model: BELL 47G-3B-1
- Registry model: [Bell 47G-3B-1](https://openairdocs.org/model/bell-47g-3b-1) (registry code 1181028) (OpenAirDocs)
- Category: Helicopter
- Serial number: 67-17111
- Engines: LYCOMING TVO-435-G1A 280 horsepower reciprocating
- Damage: Substantial damage
- Flight: Aerial application, Part 137
- Operator: Valley Air
- Registered owner: Danny L. Turner
- Airworthiness certificate: Standard, Normal
- Airport: 42J, Keystone Airpark

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 41; commercial; airplane ratings: single-engine land; instrument ratings: helicopter, airplane; medical: class 2, valid medical--no waivers/lim.; seat: right; flight hours: 11,800 total

## Weather

- Conditions: Visual (VMC), Day
- Wind: 130° at 6 knots
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 82 °F, dew point 73 °F
- Altimeter: 30.00 inHg
- Observed at: GNV, 15 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 19890530013449A](https://openairdocs.org/incident/19890530013449A), May 30, 1989: Bell 47G3B1, Keystone Height, FL, Substantial damage. Lost tail rotor control on start of spray run. Autorotated safely. Tail rotor drive shaft became uncoupled.

## Other investigations on N53SP (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 MIA00LA257](https://openairdocs.org/ntsb/MIA00LA257), Sep 1, 2000: Bell 47G-3B-1 (N53SP), Canton, MS, destroyed. Probable cause: The pilot's inadequate visual lookout which resulted in the helicopter colliding with power lines, catching fire, and being consumed by fire after landing.
- [NTSB MIA86LA222](https://openairdocs.org/ntsb/MIA86LA222), Jun 20, 1986: Bell 47G3B1 (N53SP), Cleveland, MS, 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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