SEA98LA079

NTSB accident investigation · Air Tractor AT-301 · Idaho Falls, ID · May 19, 1998

Accident · No injuriesLimited investigationFinal report
Date
May 19, 1998, 06:30 local (12:30 UTC)
Place
Idaho Falls, ID
Injuries
1 uninjured
Damage
Substantial damage
Phase of flight
Landing
Aircraft
N4326SAir Tractor AT-301
Weather
Visual (VMC) · Dawn
Status
Completed · report February 11, 2000
Report
Approved by Office Director
FAA report
19980519010269A
Case key
42788

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

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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

NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.

Loss of engine power(partial) - nonmechanicalLanding - aborted
Mixture - improperPilot in commandFactor
Mixture - not correctedPilot in commandCause
Nose overLanding - roll
Weather condition - tailwindFactor
In-flight planning/decision - inadequatePilot in commandCause
Aborted landing - discontinuedPilot in command
Aircraft control - not maintainedPilot in commandCause

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
Reported as
Air Tractor AT-301
Category
Airplane
Serial number
301-0006
Airframe hours
8,031
Engine
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

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
36
Certificates
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.

Other investigations on N4326S · 3

Matched to the same aircraft by N-number and date.