# NTSB SEA91LA105: Grumman G-164A, N8792H, Lapwai, ID, May 14, 1991

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Limited investigation · Final report
- Date: May 14, 1991, 12:30 local (19:30 UTC)
- Place: Lapwai, ID
- Coordinates: 46.319725, -116.780128 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=46.3197&lon=-116.7801&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Serious injuries
- Injuries: 1 serious
- Status: Completed, report February 8, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 41429
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA91LA105
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/41429/pdf
- Page: https://openairdocs.org/ntsb/SEA91LA105

## Probable cause

THE PILOT'S MISJUDGMENT OF AN AERIAL APPLICATION SWATH RUN.  FACTORS INCLUDE A DOWNDRAFT CONDITION AND SOFT TERRAIN.

## Sequence of events

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

- In flight collision with terrain/water, maneuvering - aerial application
  - terrain condition - crop
  - terrain condition - soft (contributing factor)
  - weather condition - downdraft (contributing factor)
  - maneuver - misjudged (cause)
  - low pass - misjudged (contributing factor)

## Analysis

THE PILOT STATED THAT HE ENCOUNTERED DOWNDRAFTS AND RAPID SINK AT THE EDGE OF THE FIELD HE WAS PREPARING TO SPRAY DURING AERIAL APPLICATION ACTIVITY. HE ATTEMPTED TO CORRECT, BUT THE MAIN LANDING GEAR TOUCHED THE CROPS AND THE AIRCRAFT TOUCHED DOWN IN THE MUDDY SOIL.  THE AIRCRAFT SLID TO A STOP AND STARTED BURNING.

## Aircraft

- Registration: [N8792H](https://openairdocs.org/deregistered/N8792H-1991-10-03), registration cancelled 1991-10-03, S/N 1530 (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)
- Category: Airplane
- Serial number: 1530
- Engines: P&W R-1340-AN1 600 horsepower reciprocating
- Damage: Destroyed
- Fire: On-Ground
- Flight: Aerial application, Part 137
- Operator: Schumacher Agri-Flite, Inc
- Registered owner: Schumacher Agri-Flite, Inc
- Airworthiness certificate: Special, Restricted (Special)
- Departed: LWS, LEWISTON, ID

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 33; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; flight hours: 2,411 total, 170 in this make and model, 2,295 as pilot in command, 196 in the last 90 days, 75 in the last 30 days, 4 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 330° at 7 knots
- Visibility: 30 statute miles
- Lowest ceiling: 12,000 ft overcast
- Temperature: 61 °F, dew point 39 °F
- Altimeter: 30.00 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 19910514016529A](https://openairdocs.org/incident/19910514016529A), May 14, 1991: Scwzer G164A, Lapwai, ID, Destroyed. Encountered downdraft at end of field. Main gear hit muddy ground. Impact tore off engine. Aircraft totaled by fire

## Other investigations on N8792H (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 SEA89LA059](https://openairdocs.org/ntsb/SEA89LA059), Mar 25, 1989: Grumman-Schweizer G-164A (N8792H), Rosalia, WA, substantial damage. Probable cause: A LOSS OF ENGINE POWER DUE TO A SUPERCHARGER FAILURE. CONTRIBUTING TO THE ACCIDENT WAS THE SOFT TERRAIN ON WHICH THE FORCED LANDING WAS MADE.
- [NTSB CHI76FEE16](https://openairdocs.org/ntsb/CHI76FEE16), Aug 29, 1975: Grum Amer G-164A (N8792H), Harvard, IL, 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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