# NTSB CEN21LA110: Air Tractor AT-502, N4540C, Cushing, OK, January 9, 2021 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 4 · Limited · Final report - Date: January 9, 2021, 14:50 local (20:50 UTC) - Place: Cushing, OK - Coordinates: 35.939235, -96.820585 - Nearby events: https://openairdocs.org/map.md?lat=35.9392&lon=-96.8206&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Defining event: [Takeoff: Aerodynamic stall/spin](https://openairdocs.org/ntsb-events/241) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 4 - Basic report with no Prelim publish - NTSB office: Central Region - Parties: FAA FSDO - NTSB case key (mKey): 102517 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN21LA110 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/102517/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=102517 - Page: https://openairdocs.org/ntsb/CEN21LA110 ## Probable cause The pilot’s decision to takeoff from unsuitable terrain which resulted in an aerodynamic stall and subsequent impact with terrain. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Info processing/decision: decision making/judgment](https://openairdocs.org/ntsb-findings/02041520): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Air Tractor AT-502, 6 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md?model=0390303), [All aircraft, 3,098 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md) - [Runway/land/takeoff/taxi surface: soft surface](https://openairdocs.org/ntsb-findings/03023020): Environmental issues › Physical environment · Decision related to condition (probable cause); cases with it: [Air Tractor AT-502, 1 case](https://openairdocs.org/ntsb-findings/03023020/cases.md?model=0390303), [All aircraft, 264 cases](https://openairdocs.org/ntsb-findings/03023020/cases.md) - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Air Tractor AT-502, 8 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=0390303), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) - [Performance/control parameters: airspeed](https://openairdocs.org/ntsb-findings/01062010): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Air Tractor AT-502, 4 cases](https://openairdocs.org/ntsb-findings/01062010/cases.md?model=0390303), [All aircraft, 1,681 cases](https://openairdocs.org/ntsb-findings/01062010/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Takeoff: Aerodynamic stall/spin](https://openairdocs.org/ntsb-events/241) (defining event); cases with it: [Air Tractor AT-502, 2 cases](https://openairdocs.org/ntsb-events/241/sequence.md?model=0390303), [All aircraft, 1,529 cases](https://openairdocs.org/ntsb-events/241/sequence.md) ## Analysis The pilot stated that he intended to depart from a soft, muddy runway and was having a difficult time becoming airborne. When the airplane reached a spot of the runway that was not as muddy, the airplane “popped out of the mud” and reached an altitude of about 30 ft above the ground. Before he could lower the nose to gain airspeed, the left wing stalled and the airplane impacted the surrounding terrain resulting in substantial damage to the fuselage, tail, and both wings. The pilot stated that there were no mechanical anomalies with the airplane that would have precluded normal operations. ## Aircraft - Registration: [N4540C](https://openairdocs.org/deregistered/N4540C-2022-11-21), registration cancelled 2022-11-21, S/N 502-0119 (OpenAirDocs) - Reported make and model: AIR TRACTOR INC AT-502 - Registry model: [Air Tractor AT-502](https://openairdocs.org/model/air-tractor-at-502) (registry code 0390303) (OpenAirDocs) - Category: Airplane - Serial number: 502-0119 - Year built: 1991 - Damage: Substantial damage - Flight: Aerial application, Part 137 - Operator: Skyler Blue LLC - Registered owner: Skyler Blue LLC - Airworthiness certificate: Standard, Normal; Special, Restricted (Special) - Destination: Same as departure - Airport: PVT, Private ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 35; injuries: none; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; last flight review September 6, 2020; seat: single; restraint: 4-point; flight hours: 1,198.8 total, 666.2 in this make and model, 1,145.8 as pilot in command, 15 in the last 90 days, 5 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 30° at 3 knots - Visibility: 10 statute miles - Temperature: 43 °F, dew point 28 °F - Altimeter: 30.33 inHg - Observed at: KCUH, 2 nm away - METAR: KCUH 092115Z AUTO 03003KT 10SM CLR 06/M02 A3033 RMK AO2 T00611020 ## 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 20210109004429A](https://openairdocs.org/incident/20210109004429A), Jan 9, 2021: Air Tractor Inc AT-502, Cushing, OK, Substantial damage. The pilot taxied out to the end of a private strip and noticed the ground was soft. The pilot decided to keep rolling and conduct a soft field takeoff. When… ## Other investigations on N4540C (1) 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 FTW96LA148](https://openairdocs.org/ntsb/FTW96LA148), Mar 15, 1996: Air Tractor AT-502 (N4540C), Texarkana, AR, substantial damage. Probable cause: a loss of engine power for undetermined reasons. A factor was the lack of suitable terrain for the forced landing. ## Docket (4 files) The files NTSB released with the investigation on August 17, 2021, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=102517. 4.2 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 1.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11833783&FileExtension=pdf&FileName=6120_Redacted-Rel.pdf - Pilot's statement (item 2, PDF, 1 page, 604 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11833841&FileExtension=pdf&FileName=Pilot%20Statement_Redacted-Rel.pdf - Record of conversation_pilot (item 3, PDF, 1 page, 209 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11833885&FileExtension=pdf&FileName=PIC%20Conversation%20Record-Rel.pdf - Photos (item 4, PDF, 3 pages, 1.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11833339&FileExtension=pdf&FileName=Photo%20Array-Rel.pdf 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.