Air Tractor INC AT 301 accident near Weiser, Idaho, August 2, 2016
On August 2, 2016 at about 3:35 pm local time, a 1982 Air Tractor INC AT 301, registered N23923, was substantially damaged in an accident during maneuvering (low-alt flying) near Weiser, Idaho. It was an aerial application (crop spraying) flight under agricultural flying rules (Part 137). No one was hurt; 1 person was on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
A partial loss of engine power due to an internal catastrophic failure of the master rod crankpin bearing.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 2, 2016 · about 3:35 pm local time
- Place
- Weiser, Idaho · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Air Tractor INC AT 301 NO SERIES, built 1982 · all AT 301s on the register
- Registration
- N23923 · no longer on the register · serial 301-0466
- Damage
- Substantial damage
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative final · quoted from the NTSB record
The airline transport pilot reported that, during an aerial application flight, he observed rising engine cylinder head temperatures and a partial loss of engine power. Unable to maintain altitude, he jettisoned the load of liquid fertilizer and made a forced landing to an alfalfa field. During the landing, the airplane collided with a wheel line sprinkler system. A postaccident examination of the radial engine revealed damage to the No. 1 cylinder lower piston skirt and the oil scraper ring. The inside of the piston exhibited multiple indentations consistent with continued battering. The remaining eight cylinders and pistons were removed and exhibited similar signatures. Multiple metallic fragments that resembled bearing material were found in the crankcase, and the magnetic chip detector displayed metallic debris. The master rod and link rod assembly were removed from the crankshaft, and the front side of the master rod exhibited two perpendicular dents. The master rod crankpin bearing revealed substantial wear and gouging-type damage, consistent with its failure initiating the engine failure. The master rod crankpin bearing was thinned, or gouged out, consistent with the metallic shavings found in the crankcase and oil galley. No maintenance records were provided, and the engine's service and maintenance history could not be determined.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
What happened, in order
- Loss of engine power (partial) during maneuvering (low-alt flying) defining event
- Off-field or emergency landing during landing (landing roll)
- Collision with terrain or object (not controlled flight into terrain) during landing (landing roll)
The NTSB's findings
- cause Aircraft › Aircraft power plant › Engine (reciprocating) › Recip eng cyl section › Failure
- cause Aircraft › Aircraft power plant › Engine (reciprocating) › (general) › Damaged/degraded
- Environmental issues › Physical environment › Object/animal/substance › Ground equipment › Contributed to outcome
- Environmental issues › Physical environment › Object/animal/substance › Tree(s) › Contributed to outcome
Pilot
- Certificate: airline transport pilot
- Ratings: multi-engine land; single-engine land; instructor: airplane multi-engine; instructor: airplane single-engine; instrument: airplane
- Flight time: 9,205 hours in all; 110 in this make and model; 220 in the last 90 days; 95 in the last 30 days; 6,420 as pilot in command; 500 on instruments
- Last flight review: March 21, 2016
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: sngl
- Injury: no injuries
The aircraft
- Maximum gross weight: 7,400 lb
- Seats: 1
- Landing gear: fixed
- Engine: P&W R1340 SERIES (piston); 0 hours total
The flight
- Departed from: S87 Weiser ID at 3:20 pm
- Destination: S87 Weiser ID
- Flight plan: none
Weather at the time
- Light: daylight
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 70°F (21°C), dew point 48°F (9°C)
- Altimeter: 30.00 inHg
- Observation at 3:53 pm from KONO, 13 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.