# NTSB CEN19FA117: Air Tractor AT 502, N7314D, Harlingen, TX, April 9, 2019 - Type: NTSB accident investigation - Classification: Accident · Fatal · Class 3 · Field · Final report - Date: April 9, 2019, 10:33 local (15:33 UTC) - Place: Harlingen, TX - Coordinates: 26.292499, -97.764999 - Nearby events: https://openairdocs.org/map.md?lat=26.2925&lon=-97.7650&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-low-alt flying: Low altitude operation/event](https://openairdocs.org/ntsb-events/220) - Highest injury: Fatal - Injuries: 1 fatal - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Central Region - Parties: Federal Aviation Administration - San Antonio, Air Tractor, Transportation Safety Board of Canada, Pratt & Whitney Canada - NTSB case key (mKey): 99235 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN19FA117 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/99235/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=99235 - Page: https://openairdocs.org/ntsb/CEN19FA117 ## Probable cause The pilot’s failure to maintain clearance from power transmission lines during low altitude flight operations. Contributing to the accident was the pilot’s impairment due to a sedating medication. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Impairment/incapacitation: oTC medication](https://openairdocs.org/ntsb-findings/02012030): Personnel issues › Physical · Pilot (probable cause); cases with it: [Air Tractor AT-502, 1 case](https://openairdocs.org/ntsb-findings/02012030/cases.md?model=0390303), [All aircraft, 56 cases](https://openairdocs.org/ntsb-findings/02012030/cases.md) - [Attention/monitoring: monitoring environment](https://openairdocs.org/ntsb-findings/02021545): Personnel issues › Psychological · Pilot (probable cause); cases with it: [Air Tractor AT-502, 10 cases](https://openairdocs.org/ntsb-findings/02021545/cases.md?model=0390303), [All aircraft, 809 cases](https://openairdocs.org/ntsb-findings/02021545/cases.md) - [Object/animal/substance: wire](https://openairdocs.org/ntsb-findings/03022032): Environmental issues › Physical environment · Effect on equipment (probable cause); cases with it: [Air Tractor AT-502, 6 cases](https://openairdocs.org/ntsb-findings/03022032/cases.md?model=0390303), [All aircraft, 588 cases](https://openairdocs.org/ntsb-findings/03022032/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering-low-alt flying: Low altitude operation/event](https://openairdocs.org/ntsb-events/220) (defining event); cases with it: [Air Tractor AT-502, 13 cases](https://openairdocs.org/ntsb-events/220/sequence.md?model=0390303), [All aircraft, 780 cases](https://openairdocs.org/ntsb-events/220/sequence.md) - [Maneuvering-low-alt flying: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Air Tractor AT-502, 17 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=0390303), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) - [Post-impact: Fire/smoke (post-impact)](https://openairdocs.org/ntsb-events/170); cases with it: [Air Tractor AT-502, 1 case](https://openairdocs.org/ntsb-events/170/sequence.md?model=0390303), [All aircraft, 354 cases](https://openairdocs.org/ntsb-events/170/sequence.md) ## Analysis The pilot was conducting an agricultural flight when witnesses observed the airplane flying at a low altitude before it collided with power transmission lines and terrain. The airplane was destroyed during a postimpact fire. Examination of the airplane wreckage did not reveal any preimpact mechanical malfunctions or failures that would have precluded normal operation. Toxicology testing detected the sedating antihistamine diphenhydramine in the pilot’s blood. Considering that postmortem redistribution of diphenhydramine may result in central levels being two-to-three times higher than peripheral levels, the circulating level was likely in the therapeutic range at the time of the accident. Given the pilot’s years of experience and familiarity with the agricultural airplane, it is reasonable to consider diminished reaction times and flying performance attributable to the use of sedating medication likely contributed to the accident. ## Factual narrative The airplane's hour meter was destroyed during the postimpact fire, which prevented a determination of the airplane's total service time at the time of the accident. A review of the maintenance records found no history of unresolved airworthiness issues. The operator reported that the airplane departed with 170 gallons of Jet-A fuel and 75 gallons of Malathion pesticide. On April 9, 2019, about 1033 central daylight time, an Air Tractor AT-502 airplane, N7314D, was destroyed when it was involved in an accident near Harlingen, Texas. The commercial pilot was fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 137 agricultural flight without a flight plan. The purpose of the flight was to spray pesticide over a cultivated cotton field. There were multiple witnesses who saw the low-flying airplane collide with power transmission lines as it descended into the field to be sprayed. One individual saw the airplane flying east before it made a “sharp right turn” back toward the west and the field to be sprayed. The airplane pitched down and flew over the highway from east-to-west at a low altitude. The airplane then collided with power transmission lines and exploded when it hit the ground. An autopsy of the pilot was performed by the Cameron County Forensic Department, Harlingen, Texas, which identified the cause of death as blunt force trauma. No significant natural disease was identified during the autopsy. Toxicological testing, completed by the Federal Aviation Administration’s Forensic Sciences Laboratory, identified 0.605 µg/mL of diphenhydramine in blood and detected diphenhydramine liver samples. No carboxyhemoglobin or ethanol was detected in blood samples. Diphenhydramine is a sedating antihistamine (commonly marketed as Benadryl) and is available over the counter in many products commonly used to treat colds, allergies, and insomnia. The therapeutic range is 0.025 to 0.100 µg/mL and it has a half-life of 3 to 14 hours. Diphenhydramine undergoes postmortem distribution and central levels may be two-to-three times higher than peripheral levels. The pilot's flight history was established using his logbook. He began flying agricultural operations in April 1965, and his first flight in an Air Tractor AT-502 airplane was in September 1987. He logged at least 7,500 flight hours in the accident airplane. The final logbook entry was for a flight review dated March 24, 2016, at which time he had logged about 27,400 total flight hours. The accident site was in the cotton field that the pilot intended to spray. The airplane impacted two 1.108-inch diameter, 345-kilovolt power transmission cables strung between two 136 ft tall structures along the eastern border of the field. The airplane subsequently impacted the field about 200 ft west of the powerlines (Figure 1). A fan-shaped wreckage debris field extended about 100 ft from the initial ground impact. The overall distribution of the wreckage was consistent withthe airplane traveling west-northwest when it impacted the ground. Red navigation lens material from the left wingtip was found at the initial impact with the ground. The main wreckage consisted of the fuselage, empennage, right wing, engine, and propeller. The main wreckage exhibited evidence of a prolonged postimpact ground fire. The fuselage was found upright with significant fire damage. All airframe structural components and flight control surfaces were identified at the accident site. Flight control continuity could not be established due to damage; however, all observed separations were consistent with overstress or damage sustained during the postimpact fire. The left wing was highly fragmented during impact. There were two transmission cables conjoined with the main wreckage; one wrapped around the engine and propeller shaft, and the other wrapped around the wing carry-through structure, right wing, and fuselage (Figure 2 and Figure 3). The forward face of the left main wing spar exhibited broad vertical marks 3-6 ft from the airplane centerline that were consistent with contact with a large diameter power transmission cable (Figure 3). The right wing was largely intact with fire damage to the inboard portion of the wing. Figure 1. Main Wreckage and Impact Debris Path Figure 2 – Power Transmission Cables Conjoined with Main Wreckage (red arrows point to cables) Figure 3 – Power Transmission Cables Conjoined with Right Wing (Left Image) and Cable Impact Marks to the Forward Face of the Left Main Wing Spar (Right Image) Engine control continuity could not be established due to impact and fire damage. The first-stage compressor blades exhibited a tip rub and ingested dirt and organic matter. The engine was separated at the C flange to review the turbine section. The downstream side of the compressor turbine disc and blades exhibited rotational scoring from contact with the power turbine vane and baffle. A majority of the power turbine blades had separated from the disc. Several power turbine blade roots and tips were found preceding the main wreckage in the debris field. The remaining turbine blades were displaced forward in the disc and were fractured close to midspan of the airfoil. The disc and blades exhibited rotational scoring on the upstream side from contact with the power turbine baffle and vane. The downstream side of the power turbine blades and disc exhibited rotational scoring from contact with the exhaust duct. The propeller remained attached to the engine. The three propeller blades remained attached to the hub and exhibited spanwise twisting. Two blades segmented during the impact sequence and one blade remained intact with leading and trailing edge gouging near the blade tip. The intact blade also exhibited minor chordwise scratches about midspan. The postaccident examination did not reveal any anomalies that would have precluded normal operation of the airplane before it collided with the high-voltage power transmissionlines. ## Aircraft - Registration: [N7314D](https://openairdocs.org/deregistered/N7314D-2019-04-18), registration cancelled 2019-04-18, S/N 502-0003, built 1987 (OpenAirDocs) - Reported make and model: Air Tractor AT 502 - Registry model: [Air Tractor AT-502](https://openairdocs.org/model/air-tractor-at-502) (registry code 0390303) (OpenAirDocs) - Registry engine: [Pratt & Whitney Canada PT6A-60A](https://openairdocs.org/engine/pratt-whitney-canada-pt6a-60a) (registry code 52043, turbo-prop) (OpenAirDocs) - Category: Airplane - Serial number: 502-0003 - Year built: 1987 - Airframe hours: 10822.8 - Engines: Pratt & Whitney PT6A-15AG 680 horsepower turbo prop - Damage: Destroyed - Fire: On-Ground - Flight: Aerial application, Part 137 - Operator: Rowland Dusters - Registered owner: Bennard Strauss Rowland II - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, April 1, 2018 - Departed: PVT, Raymondville, TX - Destination: PVT, Raymondville, TX - Equipment: Stall warning system, Data recorder ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 77; injuries: fatal; commercial; airplane ratings: single-engine land, multi-engine land; medical: class 2, with waivers/limitations; last flight review March 24, 2016; seat: center; restraint: 4-point; toxicology performed; flight hours: 27,400 total, 7,500 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 190° at 15 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 82 °F, dew point 57 °F - Altimeter: 29.97 inHg - Observed at: HRL, 8 nm away - METAR: METAR KHRL 091552Z 19015KT 10SM CLR 28/14 A2997 RMK AO2 SLP148 T02780139= ## 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 20190409002669A](https://openairdocs.org/incident/20190409002669A), Apr 9, 2019: Air Tractor Inc AT-502, Harlingen, TX, Destroyed, 1 fatal. On 04/09/2019, the pilot was making his second aerial application for the day. Witnesses on the ground noted the pilot was coming in towards the cotton field… ## Docket (12 files) The files NTSB released with the investigation on July 15, 2022, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=99235. 21.8 MB in all. - Witness statements (item 1, PDF, 5 pages, 1.9 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13995664&FileExtension=pdf&FileName=01%20-%20Witness%20Statements_Redacted-Rel.pdf - Pilot logbook (excerpts) (item 2, PDF, 89 pages, 12.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13995674&FileExtension=pdf&FileName=02%20-%20Pilot%20Logbook%20(Excerpts)_Redacted-Rel.pdf - Airframe logbook (excerpts) (item 3, PDF, 10 pages, 1.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13995311&FileExtension=pdf&FileName=03%20-%20Airframe%20Logbook%20(Excerpts)_Redacted-Rel.pdf - Engine logbook (excerpts) (item 4, PDF, 6 pages, 815 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13995684&FileExtension=pdf&FileName=04%20-%20Engine%20Logbook%20(Excerpts)_Redacted-Rel.pdf - Propeller logbook (excerpts) (item 5, PDF, 5 pages, 1.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13995140&FileExtension=pdf&FileName=05%20-%20Propeller%20Logbook%20(Excerpts)_Redacted-Rel.pdf - NTSB accident site and wreckage examination summary (item 6, PDF, 5 pages, 3 photos, 579 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=14112380&FileExtension=pdf&FileName=06%20-%20NTSB%20Accident%20Site%20and%20Wreckage%20Examination%20Summary-Rel.pdf - NTSB medical factual report (item 7, PDF, 2 pages, 77 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13995223&FileExtension=pdf&FileName=09%20-%20NTSB%20Medical%20Factual%20Report-Rel.pdf - Pilot toxicology report (item 8, PDF, 1 page, 197 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13995765&FileExtension=pdf&FileName=11%20-%20Pilot%20Toxicology_Redacted-Rel.pdf - Weather data (item 9, PDF, 1 page, 65 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13995423&FileExtension=pdf&FileName=14%20-%20Weather-Rel.pdf - Statement of party representatives to NTSB investigation (item 10, PDF, 1 page, 218 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13995775&FileExtension=pdf&FileName=15%20-%20NTSB%20Party%20Form_Redacted-Rel.pdf - Release of aircraft wreckage, NTSB form 6120.15 (item 11, PDF, 1 page, 492 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13996159&FileExtension=pdf&FileName=16%20-%20Wreckage%20Release_Redacted-Rel.pdf - Photos (item 12, PDF, 8 pages, 8 photos, 2.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13995879&FileExtension=pdf&FileName=17%20-%20Photos-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.