# NTSB DEN87LA084: Air Tractor AT-301, N23069, Conrad, MT, April 5, 1987

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: April 5, 1987, 14:00 local (21:00 UTC)
- Place: Conrad, MT
- Coordinates: 48.199542, -111.850395 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=48.1995&lon=-111.8504&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report May 19, 1989
- Report: Approved by Office Director
- NTSB case key (mKey): 17190
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN87LA084
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/17190/pdf
- Page: https://openairdocs.org/ntsb/DEN87LA084

## 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, cruise - normal
  - eng assembly,blower/impeller/integral supercharger - foreign object damage (cause)
  - maintenance - improper, other maintenance personnel (cause)
  - ignition system,magneto - failure,total (contributing factor)
  - ignition system,spark plug - shorted (contributing factor)
- Forced landing, descent - emergency
- In flight collision with terrain/water, landing - flare/touchdown
  - terrain condition - dirt bank/rising embankment (contributing factor)
  - proper touchdown point - misjudged, pilot in command (contributing factor)

## Analysis

AN AG PLT WAS RETURNING FROM AN AERIAL APPLICATION. SIX MILES FROM THE DESTINATION ARPT THE ENGINE QUIT. THE PLT ATTEMPTED TO LAND ON A ROAD BUT THE ACFT STRUCK THE EDGE OF A PIT, SPUN ACROSS THE ROAD AND CAME TO REST FACING 180 DEGREES FROM THE ORIGINAL HEADING. ENGINE EXAMINATION DISCLOSED SUPERCHARGER IMPELLER DAMAGE TYPICAL OF FOREIGN OBJECT INGESTION. FIVE OF THE NINE CYLINDERS HAD LOW COMPRESSION AND SHOWED METAL PARTICLES ON PISTON AND VALVE SURFACES. THE LEFT MAGNETO HAD BRASS, COPPER, AND ALUMINUM PARTICLES THROUGHOUT THE INTERIOR AND FAILED TO PRODUCE SPARK WHEN ROTATED. THE RIGHT MAGNETO DID PRODUCE SPARK WHEN ROTATED BUT THREE OF THE NINE PLUGS SERVED BY THIS MAGNETO WERE METAL FOULED IN THE ELECTRODES.

## Aircraft

- Registration: [N23069](https://openairdocs.org/aircraft/N23069), registered now, S/N 301-0350, built 1981 (OpenAirDocs)
- Reported make and model: AIR TRACTOR AT-301
- Registry model: [Air Tractor AT-301](https://openairdocs.org/model/air-tractor-at-301) (registry code 0390103) (OpenAirDocs)
- Registry engine: [Pratt & Whitney R1340 series](https://openairdocs.org/engine/pratt-whitney-r1340-series) (registry code 52016, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 301-0350
- Airframe hours: 1095
- Engines: P&W R-1340-AN-1 600 horsepower reciprocating
- Damage: Substantial damage
- Flight: Aerial application, Part 137
- Registered owner: Mark G. Mamuzich
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: Annual, March 1, 1987, 12 hours before

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 27; commercial; airplane ratings: multi-engine land, single-engine land; medical: class 2, valid medical--no waivers/lim.; seat: front; flight hours: 2,404 total, 934 in this make and model, 1,627 as pilot in command, 21 in the last 90 days, 2 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 40 statute miles
- Lowest ceiling: none
- Temperature: 63 °F, dew point 37 °F
- Altimeter: 29.00 inHg
- Observed at: CTB, 28 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 19870405008359A](https://openairdocs.org/incident/19870405008359A), Apr 5, 1987: Airtrc AT301, Conrad, MT, Substantial damage. The aircraft was forced to land after engine failure. Turbocharger damaged by loose washer. One magneto had failed.

## Other investigations on N23069 (3)

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 CEN25LA306](https://openairdocs.org/ntsb/CEN25LA306), Aug 7, 2025: Air Tractor AT-301 (N23069), Davenport, ND, substantial damage, investigation ongoing
- [NTSB DEN83LA136](https://openairdocs.org/ntsb/DEN83LA136), Jun 9, 1983: Air Tractor AT-301 (N23069), Conrad, MT, substantial damage
- [NTSB DEN82DTI09](https://openairdocs.org/ntsb/DEN82DTI09), Jan 3, 1982: Air Tractor AT-301 (N23069), Greenough, MT, 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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