# NTSB ERA25LA079: Air Tractor AT504, N8516V, Big Cypress, FL, December 18, 2024 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: December 18, 2024, 16:27 local (21:27 UTC) - Place: Big Cypress, FL - Coordinates: 26.33774, -81.016757 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=26.3377&lon=-81.0168&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-descent: Flight control sys malf/fail](https://openairdocs.org/ntsb-events/333) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Eastern Region Aviation - Parties: Transportation Safety Board of Canada, Air Tractor, Inc., FAA/FSDO - NTSB case key (mKey): 199445 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA25LA079 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/199445/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=199445 - Page: https://openairdocs.org/ntsb/ERA25LA079 ## Probable cause The pilot’s decision to depart with cargo outside of the designated baggage compartment, which resulted in the cargo interfering with the rudder control system. ## 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: [All aircraft, 3,098 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md) - [Loading](https://openairdocs.org/ntsb-findings/01011500): Aircraft › Aircraft handling/service · Incorrect use/operation (probable cause); cases with it: [All aircraft, 35 cases](https://openairdocs.org/ntsb-findings/01011500/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Prior to flight: Aircraft loading event](https://openairdocs.org/ntsb-events/010); cases with it: [All aircraft, 84 cases](https://openairdocs.org/ntsb-events/010/sequence.md) - [Enroute-descent: Flight control sys malf/fail](https://openairdocs.org/ntsb-events/333) (defining event); cases with it: [All aircraft, 410 cases](https://openairdocs.org/ntsb-events/333/sequence.md) - [Enroute-descent: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) ## Analysis During the first leg of a ferry flight the pilot reported that, while descending through 9,000 ft above ground level (agl), the airplane yawed left violently. Even with application of pressure to the right rudder pedal, the airplane continued in a left descending turn until impacting swampy terrain. The airplane sustained substantial damage to the left wing and engine mounts. Postaccident examination of the airplane revealed that a large amount of baggage and cargo had been zip-tied to the tubular metal fuselage structure aft of the baggage compartment and under the cockpit area. Multiple zip ties were found cut and others were found loose. The loose and cut zip ties were found in the vicinity and around a large piece of spray equipment that had been wrapped in plastic, as well as a box both, both of which could be moved by hand when pressure was applied. These items were in the vicinity of both the right rudder direct drive cable and the right rudder/aileron interconnect cable. The examination otherwise found no evidence of any preaccident mechanical malfunctions or failures of the airplane that would have precluded normal operation. Based on this information it is likely that the cargo shifted during the flight and interfered with the rudder control system, resulting in the rudder hard over. The weight and balance filled out by the pilot prior to the flight showed that he had accounted for cargo and baggage outside the airplane’s designated baggage compartment. While this showed that the airplane was likely being operated within its center of gravity envelope it, the pilot’s decision to operate the flight with cargo outside the designated area did not account for the potential that the cargo would shift in such a way that it could interfere with the flight controls. ## Factual narrative On December 18, 2024, at 1627 eastern standard time, an Air Tractor AT504, N8516V, was substantially damaged when it was involved in an accident near Big Cypress, Florida. The commercial pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 ferry flight. The pilot reported that he departed Bourland Field Airport (50F), Fort Worth, Texas, destined for Fort Lauderdale Executive Airport (FXE), Fort Lauderdale, Florida. Upon beginning his descent from cruise, while passing through about 9,000 ft agl, the pilot felt a “sudden violent yaw left.” He attempted to apply right rudder but was unable to arrest the yaw; he then applied right aileron, which also did not stop the left yaw. He declared “MAYDAY” with Miami Air Route Traffic Control Center, reporting the rudder issue. He continued in a left turning descent and impacted the ground in a swampy area. Postaccident examination found substantial damage to the left wing and the engine mount. Further detailed examination of the airframe was conducted and found the right rudder control horn and right rudder limit stop were bent upward consistent with impact. The rudder was able to move to the left limit but not to the right limit when initially tested. The left and right rudder cables were found to be continuous from the rudder control horn to the rudder pedals. The rudder cables were traced and found to be continuous from the rudder control horn to the rudder interconnect system. The left- and right-seat rudder push rods were traced and found to be continuous to the rudder interconnect system. All members and fasteners in the rudder interconnect system were found to be in their correct respective locations. During the examination the right rudder control horn was bent downward, from the as initially observed position, toward a normal position and the rudder was able to move from stop to stop using the rudder pedals in the cockpit. The examination found that there were no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation. During the examination the fuselage skin panels were removed; a large amount of baggage and cargo was observed to be zip-tied to the tubular metal fuselage structure aft of the baggage compartment and under the cockpit area. Multiple zip ties were found cut and others were found loose. These zip ties were intertwined with the cargo in the vicinity of the rudder/aileron interconnect cable and rudder direct drive cable. There was a box and large piece of plastic-wrapped spray equipment, which could be moved by hand from side to side, in the vicinity of the rudder/aileron interconnect cable. The personnel who recovered the airplane from the accident site reported that they did not cut any of the zip ties during the recovery process. When asked about the cargo the pilot stated, “Items from the spray system are usually positioned outside the cockpit and baggage area secured with XL tywraps.” A review of weight and balance information provided by the pilot listed multiple pieces of baggage and cargo outside of the baggage compartment. The calculated weight and balance was within the center of gravity envelope. ## Aircraft - Registration: N8516V (not matched to a registry record) - Reported make and model: AIR TRACTOR AT504 - Category: Airplane - Serial number: 504-4055 - Year built: 2024 - Airframe hours: 11.9 - Engines: Pratt & Whitney Canada PT6A-34AG 750 horsepower turbo prop - Damage: Substantial damage - Flight: Ferry, Part 91 - Operator: Servicios Aeronauticos Airtech Limitada - Registered owner: Servicios Aeronauticos Airtech Limitada - Airworthiness certificate: Special, Special flight (Special) - Departed: 50F, Cresson, TX - Destination: FXE, Ft. Lauderdale, FL - Equipment: Handheld GPS, ADS-B ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 46; injuries: none; commercial; airplane ratings: single-engine land; medical: class 2, with waivers/limitations; last flight review July 12, 2023; seat: left; restraint: 5-point; flight hours: 5,844 total, 6 in this make and model, 5,844 as pilot in command, 104 in the last 90 days, 65 in the last 30 days, 6 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Temperature: 32 °F, dew point 32 °F - Altimeter: 30.02 inHg - Observed at: IMM, 24 nm away - METAR: METAR KIMM 182125Z AUTO 00000KT 10SM A3002 RMK AO2 ## 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 20241218019229A](https://openairdocs.org/incident/20241218019229A), Dec 18, 2024: Air Tractor Inc AT-504, Big Cypress, FL, Substantial damage. At an altitude of approx. 9000 feet, pilot said he felt a "violent yaw" to the left but stated he never heard any Associated noises. He pushed the right rudder… ## Docket (11 files) The files NTSB released with the investigation on August 20, 2025, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=199445. 16.4 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 10 pages, 1.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18708450&FileExtension=pdf&FileName=ERA25LA079%206120.1%20Printed_Redacted-Rel.pdf - FAA interview of pilot (item 2, PDF, 2 pages, 275 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18708689&FileExtension=pdf&FileName=FAA%20Inspector%20Interview%20of%20Pilot-Rel.pdf - Memorandum for record a�� questions to pilot (item 3, PDF, 2 pages, 86 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18710162&FileExtension=pdf&FileName=MOR%20Questions%20for%20Pilot-Rel.pdf - Air tractor AT504 airplane flight manual excerpts (item 4, PDF, 5 pages, 655 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18709575&FileExtension=pdf&FileName=AT504%20AFM%20Excerpts-Rel.pdf - Weight and balance provided by pilot (item 5, PDF, 1 page, 57 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18709751&FileExtension=pdf&FileName=Weight%20and%20Balance%20N8516V%20by%20Pilot-Rel.pdf - Flight track (item 6, KMZ, 1.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18709761&FileExtension=kmz&FileName=20241218_ABAE4D_574598150-Rel.kmz - Photos (item 7, PDF, 5 pages, 3.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18709771&FileExtension=pdf&FileName=Photo%20Array%20ERA25LA079-Rel.pdf - Wreckage examination (item 8, PDF, 23 pages, 8.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18709951&FileExtension=pdf&FileName=ERA25LA079%20Wreckage%20Examination_Redacted-Rel.pdf - Memorandum for record a�� recovery company information (item 9, PDF, 1 page, 62 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=19065806&FileExtension=pdf&FileName=MOR%20Recovery%20Crew-Rel.pdf - Statement of party representatives to NTSB investigation (item 10, PDF, 14 pages, 418 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18710213&FileExtension=pdf&FileName=Air%20Tractor%20Party%20Form_Redacted-Rel.pdf - Release of aircraft wreckage, NTSB form 6120.15 (item 11, PDF, 1 page, 710 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18719477&FileExtension=pdf&FileName=ERA25LA079%20Signed%20Wreckage%20Release%20Print_Redacted-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.