# NTSB LAX92LA131: Grumman G-164A, N5408, Vernalis, CA, February 29, 1992

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: February 29, 1992, 09:30 local (17:30 UTC)
- Place: Vernalis, CA
- Coordinates: 37.610275, -121.250549 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=37.6103&lon=-121.2505&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report August 26, 1993
- Report: Approved by Office Director
- ADs cited in the narratives: [AD 86-08-06 R1](https://openairdocs.org/ad/86-08-06-R1) (OpenAirDocs)
- NTSB case key (mKey): 27568
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX92LA131
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/27568/pdf
- Page: https://openairdocs.org/ntsb/LAX92LA131

## Probable cause

THE OPERATOR'S FAILURE TO PROPERLY COMPLY WITH AN AIRWORTHINESS DIRECTIVE AFFECTING THE SECOND-STAGE TURBINE WHEEL ASSEMBLY.  CONTRIBUTING TO THIS ACCIDENT WAS THE UNCONTAINED FAILURE OF THE SECOND-STAGE TURBINE WHEEL AND THE ROUGH/UNEVEN TERRAIN.

## Sequence of events

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

- Loss of engine power(total) - mech failure/malf, maneuvering
  - turbine assembly,turbine wheel - failure,total (contributing factor)
  - maintenance,compliance with ad - improper, company maintenance personnel (cause)
- Forced landing, descent - emergency
- Nose over, landing - roll
  - terrain condition - rough/uneven (contributing factor)

## Analysis

THE AIRPLANE EXPERIENCED AN UNCONTAINED SEPARATION OF THE SECOND-STAGE STATOR TURBINE WHEEL WHILE EXECUTING AN AERIAL APPLICATION PROCEDURE TURN. THE AIRPLANE'S ALTITUDE WAS INSUFFICIENT FOR THE PILOT TO ALIGN IT WITH THE CULTIVATED FURROWS.  THE LANDING WAS NORMAL BUT THE AIRPLANE NOSED OVER ONTO ITS BACK DURING THE LANDING ROLL WHEN THE WHEELS DUG INTO THE FURROWS.  EXAMINATION OF THE ENGINE'S LOGBOOK DISCLOSED THAT THE OPERATOR HAD NOT PROPERLY COMPLIED WITH AIRWORTHINESS DIRECTIVE (AD) 86-08-06. THIS AD REQUIRES RADIOGRAPHIC INSPECTION OF THE SECOND-STAGE STATOR TURBINE WHEEL ASSEMBLY.

## Aircraft

- Registration: [N5408](https://openairdocs.org/deregistered/N5408-2007-06-25), registration cancelled 2007-06-25, S/N 981, built 1972 (OpenAirDocs)
- Reported make and model: GRUMMAN 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)
- Registry engine: [AiResearch TPE331 series](https://openairdocs.org/engine/airesearch-tpe331-series) (registry code 01517, turbo-prop) (OpenAirDocs)
- Category: Airplane
- Serial number: 981
- Airframe hours: 4058
- Engines: GARRETT TPE 331-43BL 575 horsepower turbo prop
- Damage: Substantial damage
- Flight: Aerial application, Part 137
- Operator: Trinkle & Boys Agricultural
- Registered owner: Trinkle & Boys Agricultural
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: Annual, April 4, 1991, 362 hours before

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 39; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane, helicopter; medical: class 2, valid medical--no waivers/lim.; seat: front; flight hours: 7,729 total, 1,773 in this make and model, 7,412 as pilot in command, 128 in the last 90 days, 88 in the last 30 days, 6 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 10 statute miles

## 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 19920229004689A](https://openairdocs.org/incident/19920229004689A), Feb 29, 1992: Scwzer G164A, Vernalis, CA, Substantial damage. Second stage turbine inner seal contacted turbine wheel caused engine blowup. AD on problem not fully complied.

## Other investigations on N5408 (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 FTW76DRA30](https://openairdocs.org/ntsb/FTW76DRA30), Apr 10, 1976: Grumman G-164A (N5408), Damon, TX, 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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