# NTSB SEA98LA079: Air Tractor AT-301, N4326S, Idaho Falls, ID, May 19, 1998 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: May 19, 1998, 06:30 local (12:30 UTC) - Place: Idaho Falls, ID - Coordinates: 43.430194, -111.889587 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=43.4302&lon=-111.8896&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report February 11, 2000 - Report: Approved by Office Director - NTSB case key (mKey): 42788 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA98LA079 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/42788/pdf - Page: https://openairdocs.org/ntsb/SEA98LA079 ## Probable cause The pilot's inadequate inflight decision to land with a tailwind and his failure to maintain aircraft control. Also contributing was the pilot's improper setting of the fuel mixture which resulted in a partial loss of engine power. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power(partial) - nonmechanical, landing - aborted - mixture - improper, pilot in command (contributing factor) - mixture - not corrected, pilot in command (cause) - Nose over, landing - roll - weather condition - tailwind (contributing factor) - in-flight planning/decision - inadequate, pilot in command (cause) - aborted landing - discontinued, pilot in command - aircraft control - not maintained, pilot in command (cause) ## Analysis As the pilot approached the agricultural application airstrip, he decided that he would land downwind so that he would end his landing roll near the equipment that would be used to load the aircraft. After the aircraft touched down, the pilot became uncomfortable with the downwind landing, and elected to make a go-around. He applied power two separate times during the attempted go-around, but both times the engine coughed and sputtered and would not accelerate. The pilot therefore decided to abort the go-around, and attempted to stop the aircraft in the remaining runway. According to the pilot, as the aircraft was slowing, the tailwind picked up the aft end of the aircraft and caused it to nose over. In a post- accident telephone interview, the pilot said that he had failed to readjust the engine fuel mixture from its more-lean cruise setting prior to landing. He further stated that the engine had been working fine, and that he felt sure that if he had adjusted the mixture prior to landing that the engine would have accelerated when he added power for the go-around. ## Factual narrative On May 19, 1998, approximately 0630 mountain daylight time, an Air Tractor AT-301, N4326S, nosed over during an aborted landing at an agricultural application airstrip about three miles northwest of Idaho Falls, Idaho. The airline transport pilot, who was the sole occupant, was not injured, but the aircraft, which was owned and operated by Lewis Flying Service, sustained substantial damage. The 14 CFR Part 91 repositioning flight, which departed Rigby-Jefferson County Airport, about 15 minutes earlier, was being operated in visual meteorological conditions at the time of the accident. According to the pilot, he elected to land with a tailwind because landing in that direction would allow him to come to a stop near the equipment that was going to be used to load chemicals into the aircraft. He said that after the aircraft touched down, he became uncomfortable with the downwind landing, and elected to execute a go-around. When he applied power, the engine coughed and did not accelerate, so he retarded the throttle and then applied power a second time. During the second power application, the engine again coughed and failed to accelerate, so the pilot retarded the power to idle and attempted to complete the landing. During the landing roll, the pilot brought the stick to the full-aft position, and the tailwheel settled onto the terrain. But, according to the pilot, as the aircraft slowed, the tailwind lifted the tail and the aircraft nosed over on the dirt airstrip. In a post-accident interview, the pilot, who had leaned the fuel mixture en route, said that the engine had been running fine prior to the attempted go-around, but that he had failed to adjust the mixture prior to the landing. He further stated that he felt that if the mixture would have been richer when he applied power for the go-around that the engine would have accelerated normally. ## Aircraft - Registration: [N4326S](https://openairdocs.org/aircraft/N4326S), registered now, S/N 301-0006 (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 R-985 series](https://openairdocs.org/engine/pratt-whitney-r-985-series) (registry code 52008, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 301-0006 - Airframe hours: 8031 - Engines: P&W 1340-AN1 600 horsepower reciprocating - Damage: Substantial damage - Flight: Other work use, Part 91 - Registered owner: Orlin D. Lewis - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, May 6, 1998, 1 hours before - Departed: U56, RIGBY, ID - Airport: Private Agricultural ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 36; flight instructor, airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: front; flight hours: 6,200 total, 6 in this make and model, 3,266 as pilot in command, 12 in the last 90 days ## Weather - Conditions: Visual (VMC), Dawn - Wind: 360° at 12 knots - Visibility: 20 statute miles - Lowest ceiling: none - Temperature: 50 °F ## 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 19980519010269A](https://openairdocs.org/incident/19980519010269A), May 19, 1998: Airtrc AT301, Idaho Falls, ID, Substantial damage. Acft landed downwind on a dirt strip and a gust of wind caught the tail and flipped the acft over. (.4)as the pilot approached the agricultural application… ## Other investigations on N4326S (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 CEN22LA354](https://openairdocs.org/ntsb/CEN22LA354), Aug 1, 2022: Air Tractor AT-301 (N4326S), Lamoni, IA, destroyed. Probable cause: A loss of airplane performance for reasons that could not be determined. - [NTSB SEA95LA154](https://openairdocs.org/ntsb/SEA95LA154), Jul 17, 1995: Air Tractor AT-301 (N4326S), Roberts, ID, substantial damage. Probable cause: A LOSS OF ENGINE POWER DUE TO THE SEPARATION OF THE NUMBER 3 CYLINDER EXHAUST VALVE ROCKER ARM SHAFT FROM THE CYLINDER HEAD, WHICH DISABLED MOVEMENT OF THE EXHAUST VALVE. A FACTOR WAS THE LACK OF… - [NTSB LAX82DA265](https://openairdocs.org/ntsb/LAX82DA265), Jul 18, 1982: Air Tractor AT-301 (N4326S), San Joaquin, CA, 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. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.