# NTSB FTW91DRD07: Grumman G-164B, N573AF, Donaldsonville, LA, July 28, 1991

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Final report
- Date: July 28, 1991, 11:00 local (16:00 UTC)
- Place: Donaldsonville, LA
- Coordinates: 30.090663, -90.98944 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=30.0907&lon=-90.9894&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report May 3, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 23226
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW91DRD07
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/23226/pdf
- Page: https://openairdocs.org/ntsb/FTW91DRD07

## Probable cause

THE MECHANICAL FAILURE OF THE PROPELLER BLADE PITCH POSITIONING BOLT. A FACTOR WAS THE LACK OF SUITABLE TERRAIN AVAILABLE FOR THE FORCED LANDING.

## Sequence of events

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

- Airframe/component/system failure/malfunction, maneuvering - aerial application
  - propeller system/accessories,counterweight - failure,total (cause)
  - aircraft control - reduced, pilot in command
- Forced landing, descent - emergency
- On ground/water encounter with terrain/water, landing - roll
  - terrain condition - ditch
  - terrain condition - none suitable (contributing factor)

## Analysis

THE PILOT EXPERIENCED A SEVERE ENGINE VIBRATION WHILE CONDUCTING AERIAL APPLICATION. THE VIBRATION WAS DUE TO THE FAILURE OF A BLADE PITCH POSITIONING BOLT WHICH RENDERED THE PROPELLER UNCONTROLLABLE. THE PILOT EXECUTED A FORCED LANDING AND COLLIDED WITH A DRAINAGE DITCH DURING THE LANDING ROLLOUT.

## Aircraft

- Registration: [N573AF](https://openairdocs.org/aircraft/N573AF), registered now, S/N 573B, built 1979 (OpenAirDocs)
- Reported make and model: GRUMMAN G-164B
- Registry model: [Grumman Acft ENG Cor-Schweizer G-164B](https://openairdocs.org/model/grumman-acft-eng-cor-schweizer-g-164b) (registry code 3952802) (OpenAirDocs)
- Registry engine: [Pratt & Whitney R1340 series](https://openairdocs.org/engine/pratt-whitney-r1340-series) (registry code 52016, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 573B
- Engines: P&W R-1340-AN1 600 horsepower reciprocating
- Damage: Substantial damage
- Flight: Aerial application, Part 137
- Operator: W.M. Melancon Enterprises, Inc, doing business as Air Farm, Inc.
- Registered owner: W.M. Melancon Enterprises, Inc
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: Annual, April 20, 1991, 439 hours before

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 45; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: center; flight hours: 12,000 total, 5,000 in this make and model, 150 in the last 90 days, 50 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 355° at 7 knots
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 91 °F, dew point 73 °F
- Altimeter: 29.00 inHg

## 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 19910728030329A](https://openairdocs.org/incident/19910728030329A), Jul 28, 1991: Scwzer G164B, Donaldsonville, LA, Substantial damage. Prop blade pitch bolt failed causing severe vibration. Struck a ditch and flipped over on forced landing.

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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