CEN23LA244

NTSB accident investigation · Air Tractor AT-502 · Sturgis, SD · June 18, 2023

Accident · No injuriesClass 4 · LimitedFinal report
Date
June 18, 2023, 13:30 local (19:30 UTC)
Place
Sturgis, SD · Runway 11 at 49B
Injuries
1 uninjured
Damage
Substantial damage
Phase of flight
Landing
Aircraft
N290LAAir Tractor AT-502
Defining event
Landing-flare/touchdown: Loss of control on ground
Weather
Visual (VMC) · Day
Status
Completed
Report
Approved by Office Director
Investigation class
Class 4 - Basic report with no Prelim publish
NTSB office
Central Region
Parties
FAA Rapid City FSDO
FAA report
20230618005079A
Case key
192396

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 improper timing to initiate beta mode with the propeller and his failure to maintain directional during the full load landing that resulted in a runway excursion. Contributing to the accident was the pilot’s lack of recent experience with performing a full load landing and the high-density altitude that likely affected aircraft performance during the landing.

Findings · 6

NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.

Use of equip/info: aircraft controlPersonnel issues › Task performance · PilotAir Tractor AT-502A: 4 casesAll aircraft: 9,295 casesProbable cause
Action: incorrect action sequencePersonnel issues › Action/decision · PilotAir Tractor AT-502A: 1 caseAll aircraft: 77 casesProbable cause
Performance/control parameters: directional controlAircraft › Aircraft oper/perf/capability · Not attained/maintainedAir Tractor AT-502A: 2 casesAll aircraft: 3,958 casesProbable cause
Temp/humidity/pressure: high density altitudeEnvironmental issues › Conditions/weather/phenomena · Effect on equipmentAir Tractor AT-502A: 1 caseAll aircraft: 278 casesProbable cause

Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.

Analysis

The pilot reported he departed in the airplane with about 660 lbs of fuel and about 3,500 lbs of liquid chemical for application to a pasture. After arriving at the pasture, the chemical dispersal system was malfunctioning, and the pilot decided to return to the airport. During the landing to the first quarter of the runway, the airplane was about 125 mph, with “half flap” applied, and the tailwheel was locked. As the tailwheel touched down on the dry concrete runway, the pilot initiated beta mode with the propeller, and the airplane “started veering to the right.” The pilot assessed that he “reversed the propeller too aggressively and too soon.” The airplane departed the runway to the right, the left main landing gear separated after impacting a ditch, and the airplane came to rest upright on a grass field. The pilot was able to egress from the airplane without further incident. The airplane sustained substantial damage to the fuselage and the left wing. The operator reported there were no preimpact mechanical malfunctions or failures with the airframe or the engine that would have precluded normal operation. A postaccident examination of the chemical dispersal system found foreign object debris that was likely blocking the flow of the chemical. Title 14 Code of Federal Regulations Part 137 Agricultural Aircraft Operations does not contain full load landing training and recurrency requirements. The pilot reported the last time he performed a full load landing was about 2 years prior. The estimated density altitude for the airport was 6,101 ft.

Aircraft

Registration
N290LA
Reported as
Air Tractor AT-502 (A)
Category
Airplane
Serial number
502A-3137
Built
2018
Airframe hours
487
Engine
Pratt & Whitney Canada PT6A-140AG, 867 horsepower, turbo prop
Damage
Substantial damage
Flight
Aerial application · Part 137
Operator
Ascend Ag Inc, doing business as Ascend Ag Inc
Registered owner
Ascend Ag Inc
Airworthiness certificate
Special, Restricted (Special)
Last inspection
Annual · January 15, 2023 · 27 hours before
Flight plan
VFR
Airport
49B · Sturgis Muni, runway 11, 5,100 × 75 ft, concrete
Equipment
Stall warning system, ADS-B

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
35
Injuries
None
Certificate
Commercial
Airplane ratings
Single-engine land
Medical
Class 2, Without waivers/limitations
Last flight review
May 22, 2022
Seat
Single
Restraint
5-point
Flight hours
1,927 total · 690 in this make and model · 1,927 as pilot in command · 70 in the last 90 days · 22 in the last 30 days

Weather

Conditions
Visual (VMC) · Day
Wind
180° at 17 knots
Visibility
10 statute miles
Lowest ceiling
None
Temperature
84 °F, dew point 48 °F
Altimeter
29.60 inHg
Observed at
KRCA, 20 nm away
METAR
KRCA 181855Z AUTO 18017KT 10SM CLR 29/09 A2960 RMK AO2 PK WND 16027/19 SLP001 T02870089 $

Docket · 4

The files NTSB released with the investigation on July 27, 2023, on NTSB’s docket system: statements, records, photos and specialists’ reports. 7.1 MB in all.

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.