# NTSB MKC89LA142: Grumman-Schweizer G-164A, N9725, Waldenburg, AR, June 23, 1989

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: June 23, 1989, 07:30 local (12:30 UTC)
- Place: Waldenburg, AR
- Location: 35.5653° N, 90.9346° W: Placed by OpenAirDocs: center of Waldenburg, AR, within about 6 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=35.5653&lon=-90.9346&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report August 2, 1990
- Report: Approved by Office Director
- NTSB case key (mKey): 34817
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=MKC89LA142
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/34817/pdf
- Page: https://openairdocs.org/ntsb/MKC89LA142

## Probable cause

THE TOTAL FAILURE OF THE ENGINE SUPERCHARGER WHICH RESULTED IN A LOSS OF ENGINE POWER.

## Sequence of events

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

- Loss of engine power(partial) - mech failure/malf, cruise
  - eng assembly,blower/impeller/integral supercharger - failure,total (cause)
- Forced landing, descent - emergency
- Nose over, landing
  - terrain condition - none suitable (contributing factor)

## Analysis

THE PILOT SAID THAT SHORTLY AFTER TAKEOFF, ENROUTE TO PERFORM AN AERIAL APPLICATION OPERATION THE ENGINE LOST POWER. AN EMERGENCY LDG WAS ATTEMPTED IN A CORN FIELD WHICH RESULTED IN A NOSE OVER. POST ACCIDENT INVESTIGATION REVEALED THE ENGINE SUPERCHARGER FAILED.

## Aircraft

- Registration: [N9725](https://openairdocs.org/deregistered/N9725-1991-12-27), registration cancelled 1991-12-27, S/N 1235 (OpenAirDocs)
- Reported make and model: GRUMMAN-SCHWEIZER G-164A
- Registry model: [Grumman Acft ENG Cor-Schweizer G-164A](https://openairdocs.org/model/grumman-acft-eng-cor-schweizer-g-164a) (registry code 3952801) (OpenAirDocs)
- Category: Airplane
- Serial number: 1235
- Airframe hours: 3965
- Engines: P&W R-1340-AN1 600 horsepower reciprocating
- Damage: Substantial damage
- Flight: Aerial application, Part 137
- Operator: Sky Hawk Inc.
- Registered owner: Sky Hawk, Inc
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: Annual, April 20, 1989, 206 hours before
- Departed: NONE, WALDENBURG, AR
- Airport: NONE

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 37; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: left; flight hours: 4,600 total, 3,700 in this make and model, 4,600 as pilot in command, 260 in the last 90 days, 125 in the last 30 days, 8 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 180° at 4 knots
- Visibility: 7 statute miles
- Lowest ceiling: none
- Temperature: 81 °F, dew point 72 °F
- Altimeter: 30.00 inHg
- Observed at: JBR, 20 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 19890623017509A](https://openairdocs.org/incident/19890623017509A), Jun 23, 1989: Scwzer G164A, Waldenburg, AR, Substantial damage. Sulper charger blower failed on takeoff. Landed in tall corn and nosed over.

## Other investigations on N9725 (1)

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 MIA74DKJ63](https://openairdocs.org/ntsb/MIA74DKJ63), Jun 16, 1974: Grumman G-164 (N9725), Moundville, AL, 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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