# NTSB LAX90DVA07: Air Tractor AT-401, N7315S, San Joaquin, CA, July 26, 1990

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Final report
- Date: July 26, 1990, 00:30 local (07:30 UTC)
- Place: San Joaquin, CA
- Coordinates: 36.589801, -120.190879 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=36.5898&lon=-120.1909&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 1 fatal
- Status: Completed, report November 23, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 26561
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX90DVA07
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/26561/pdf
- Page: https://openairdocs.org/ntsb/LAX90DVA07

## Probable cause

THE FAILURE OF THE NO. 4 CYLINDER HEAD.

## 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 - aerial application
  - engine assembly,cylinder - cracked (cause)
- Forced landing, descent - emergency
- Nose over, landing - roll

## Analysis

THE PILOT EXPERIENCED AN ENGINE FAILURE DURING AERIAL APPLICATION, LANDED IN A FIELD AND THE AIRCRAFT FLIPPED OVER. THE AIRCRAFT REMAINED INTACT WITH NO FIRE. THE PILOT EXPIRED FROM 'POSITIONAL ASPHYXIA.' EXAMINATION OF THE ENGINE REVEALED THE NO. 4 CYLINDER WAS CRACKED AROUND THE COOLING FINS AND CONTINUED THROUGH THE CENTER OF THE SPARK PLUG BOSS. THE ENGINE HAD 7251 TOTAL HOURS AND 339 HOURS SINCE OVERHAUL.

## Aircraft

- Registration: [N7315S](https://openairdocs.org/deregistered/N7315S-2009-10-22), registration cancelled 2009-10-22, S/N 401-0673, built 1987 (OpenAirDocs)
- Reported make and model: AIR TRACTOR AT-401
- Registry model: [Air Tractor AT-401](https://openairdocs.org/model/air-tractor-at-401) (registry code 0390204) (OpenAirDocs)
- Registry engine: [Pratt & Whitney R1340 series](https://openairdocs.org/engine/pratt-whitney-r1340-series) (registry code 52016, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 401-0673
- Airframe hours: 1682
- Engines: P&W R1340-AN-1 600 horsepower reciprocating
- Damage: Substantial damage
- Flight: Aerial application, Part 137
- Operator: Grouleff Aviation, Inc.
- Registered owner: Grouleff Aviation, Inc
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: Annual, April 11, 1990, 249 hours before
- Destination: CA

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 56; commercial; airplane ratings: single-engine land; medical: class 2, valid medical--w/ waivers/lim; seat: center; toxicology performed; flight hours: 16,500 total, 8,000 in this make and model, 16,500 as pilot in command, 175 in the last 90 days, 100 in the last 30 days, 7 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Night/dark
- Wind: 310° at 9 knots
- Visibility: 20 statute miles
- Lowest ceiling: none
- Temperature: 75 °F, dew point 46 °F
- Altimeter: 29.00 inHg
- Observed at: FAT, 25 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 19900726028719A](https://openairdocs.org/incident/19900726028719A), Jul 26, 1990: Airtrc AT401, San Joaquin, CA, Substantial damage, 1 fatal. Engine blew a cylinder during a spray run turn around. Aircraft flipped over landing in a sugar beet field.

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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