# NTSB ATL99LA105: Bell 47, N23590, Trenton, GA, July 2, 1999

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: July 2, 1999, 07:30 local (11:30 UTC)
- Place: Trenton, GA
- Coordinates: 34.869815, -85.500099 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=34.8698&lon=-85.5001&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 1 minor
- Status: Completed, report June 21, 2000
- Report: Approved by Office Director
- NTSB case key (mKey): 46720
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ATL99LA105
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/46720/pdf
- Page: https://openairdocs.org/ntsb/ATL99LA105

## Probable cause

The loss of main rotor rpm due to improper use of the flight controls by the pilot. Factors were the tailwind and trees.

## Sequence of events

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

- Loss of control - in flight, maneuvering
  - adequate rotor rpm - not maintained, pilot in command (cause)
  - flight controls - improper use of, pilot in command (cause)
  - weather condition - tailwind (contributing factor)
- Forced landing, emergency landing
  - autorotation - initiated, pilot in command
- In flight collision with object, emergency descent/landing
  - object - tree(s) (contributing factor)

## Analysis

According to the pilot, he was unable to maintain flight after a loss of rotor rpm. He initiated an autorotation and collided with trees during the descent. The pilot attempted the autorotation with about a five knot tail wind. The pilot reported no mechanical deficiencies with the helicopter.

## Factual narrative

On July 2, 1999, at 0730 eastern daylight time, a Bell 47, N23590, collided with trees during a forced landing near Trenton, Georgia, following a loss of rotor rpm. The agricultural flight was operated by the pilot under the provisions of Title 14 CFR Part 137, and no flight plan was filed. Visual meteorological conditions prevailed at the time of the accident. The helicopter sustained substantial damage and the commercial pilot received minor injuries. The flight departed Trenton, Georgia, at an undetermined time.

The pilot was conducting an aerial application for agricultural purposes. According to the pilot, the helicopter experienced a decay in rotor rpm and he was unable to maintain flight. He executed an autorotation and collided with trees on the descent.

According to the FAA, the pilot attempted the autorotation with about a five knot tailwind. No mechanical deficiencies were reported by the pilot. A Pilot/Operator Aircraft Accident Report (Form 6120.1/2) was not submitted by the pilot.

## Aircraft

- Registration: [N23590](https://openairdocs.org/aircraft/N23590), registered now, S/N 3506, built 1965 (OpenAirDocs)
- Reported make and model: Bell 47
- Registry model: [Bell TH-13T](https://openairdocs.org/model/bell-th-13t) (registry code 1180813) (OpenAirDocs)
- Registry engine: [Lycoming TVO-435-GIA](https://openairdocs.org/engine/lycoming-tvo-435-gia) (registry code 41526, turbo-prop) (OpenAirDocs)
- Category: Helicopter
- Serial number: 3506
- Engines: Lycoming VO-435-AIF 280 horsepower reciprocating
- Damage: Substantial damage
- Flight: Aerial application, Part 137
- Registered owner: Southern Helicopter
- Airworthiness certificate: Special, Restricted (Special)

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 52; commercial; airplane ratings: single-engine land; medical: class 2, valid medical--no waivers/lim.; seat: right; flight hours: 8,440 total, 2,450 in this make and model, 110 in the last 90 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 160° at 5 knots
- Visibility: 8 statute miles
- Lowest ceiling: none
- Temperature: 73 °F, dew point 66 °F
- Altimeter: 30.00 inHg
- Observed at: CHA, 22 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 19990702008149A](https://openairdocs.org/incident/19990702008149A), Jul 2, 1999: Trenton, GA, Substantial damage. 1965 Bell TH-13T helicopter was involved in aerial application when it crashed in the woods under unknown circumstances and sustained substantial damage. (-23)…

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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