# NTSB CHI97LA124: Air Tractor AT-301, N23640, Huron, SD, May 7, 1997 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: May 7, 1997, 11:12 local (16:12 UTC) - Place: Huron, SD - Coordinates: 44.359512, -98.209281 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=44.3595&lon=-98.2093&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report September 5, 1997 - Report: Approved by Office Director - NTSB case key (mKey): 10559 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI97LA124 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/10559/pdf - Page: https://openairdocs.org/ntsb/CHI97LA124 ## Probable cause The pilot's failure to maintain clearance from known transmission lines. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight collision with object, maneuvering - aerial application - clearance - not maintained, pilot in command (cause) - object - wire,transmission - In flight collision with terrain/water, descent - uncontrolled ## Analysis The pilot said that he had completed his turn to enter the field he was spraying. He entered the field downwind over the trees. On entering the field the airplane struck power transmission cables. The airplane impacted on the ground and came to rest in a wheat field. Examination of the wreckage showed part of a transmission line wrapped around the propeller. ## Factual narrative On May 7, 1997, at 1112 central daylight time (cdt), an Air Tractor, AT-301, N23640, operated by a commercial pilot, sustained substantial damage when during maneuvering the airplane struck some high-tension power lines. The airplane subsequently impacted the terrain, 12 miles north of Huron, South Dakota. Visual meteorological conditions prevailed at the time of the accident. The aerial application flight was being conducted under 14 CFR Part 137. A flight plan was not on file. The pilot reported no injuries. The local flight originated at Huron, South Dakota, at 1045 cdt. In his written statement, the pilot said that he had completed his turn to enter the field he was spraying. He entered the field down wind over the trees. On entering the field the airplane struck power transmission cables. The airplane impacted on the ground and came to rest in a wheat field. The Federal Aviation Administration (FAA) inspector who examined the wreckage at the scene found the airplane resting in a wheat field on its left side, approximately 400 feet northeast of a support tower for some east-west running transmission lines. Several ground impact marks were observed across the wheat field, between the transmission lines and the main wreckage, beginning 100 feet north of the transmission lines and proceeding north- northeasterly to where the fuselage came to its final rest. The left side of the airplane's fuselage was crushed in. The engine was broken free of the mounts and separated from the airplane. Both wings were separated from the airplane at the roots. The right wing was found resting next to the fuselage. It was bent, twisted, and crushed inward. The left wing was broken into several pieces and found scattered between the first impact mark and the main wreckage. Both main gear were bent up and aft onto the fuselage. The left horizontal stabilizer was broken off at the root. The vertical stabilizer, rudder, right horizontal stabilizer and right elevator were undamaged. The propeller remained attached to the flange and exhibited torsional bending and chordwise scratching. Part of a transmission line was found wrapped around the propeller. Flight control continuity was confirmed. Examination of the engine, engine controls and other airplane systems revealed no anomalies. ## Aircraft - Registration: [N23640](https://openairdocs.org/deregistered/N23640-1998-10-31), registration cancelled 1998-10-31, S/N 3010405 (OpenAirDocs) - Reported make and model: Air Tractor AT-301 - Registry model: [Air Tractor AT-301](https://openairdocs.org/model/air-tractor-at-301) (registry code 0390103) (OpenAirDocs) - Category: Airplane - Serial number: AT301-405 - Airframe hours: 4087 - Engines: P&W R-1340 600 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 137 - Registered owner: Krech & Kroeplin LLC - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, March 17, 1997, 63 hours before - Departed: HON ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 38; commercial; airplane ratings: single-engine land; medical: class 1, valid medical--w/ waivers/lim; seat: front; flight hours: 2,732 total, 812 in this make and model, 2,648 as pilot in command, 129 in the last 90 days, 129 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 190° at 8 knots - Visibility: 10 statute miles - Lowest ceiling: 3,800 ft overcast - Temperature: 57 °F, dew point 52 °F - Altimeter: 29.00 inHg - Observed at: HON, 12 nm away ## 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 19970507008419A](https://openairdocs.org/incident/19970507008419A), May 7, 1997: Airtrc AT301, Huron, SD, Substantial damage. Aircraft struck wires during aerial application and crashed. (.4)the pilot said that he had completed his turn to enter the field he was spraying. He entered… ## Other investigations on N23640 (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 MIA88LA229](https://openairdocs.org/ntsb/MIA88LA229), Jul 18, 1988: Air Tractor AT-301 (N23640), Moorhead, MS, substantial damage 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.