# NTSB FTW01LA178: Air Tractor AT-401, N10140, Grand Coteau, LA, August 9, 2001 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: August 9, 2001, 09:00 local (14:00 UTC) - Place: Grand Coteau, LA - Coordinates: 30.43053, -92.049499 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=30.4305&lon=-92.0495&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report February 20, 2002 - Report: Approved by Office Director - Parties: BTR FSDO - ADs cited in the narratives: [AD 99-11-02](https://openairdocs.org/ad/99-11-02) (OpenAirDocs) - NTSB case key (mKey): 52988 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW01LA178 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/52988/pdf - Page: https://openairdocs.org/ntsb/FTW01LA178 ## Probable cause the loss of engine power while maneuvering, which resulted from a fractured #4 cylinder head at the exhaust valve rocker arm boss. A contributing factor was the lack of suitable terrain for the forced landing. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power(total) - mech failure/malf, maneuvering - aerial application - engine assembly,cylinder - fractured (cause) - Forced landing, descent - emergency - Gear collapsed, landing - flare/touchdown - terrain condition - none suitable (contributing factor) - terrain condition - soft ## Analysis The agricultural airplane had completed a spray pass from south to north, and during a turn around maneuver, the engine lost power. The pilot emptied the airplane's load and initiated a forced landing to a dirt road; however, the aircraft was unable to reach the road. The airplane touched down in a sweet potato field perpendicular to the rows with its right wing first. Subsequently, as the airplane touched down, its main landing gear collapsed. The airplane came to rest upright. An examination of the engine revealed that the #4 cylinder head had fractured at the exhaust valve rocker arm boss. A review of the maintenance records revealed that on August 4, 2001 (4.4 hours prior to the accident), the Pratt & Whitney R-1340-AN-1 engine's cylinder heads were inspected for cracking in accordance with Airworthiness Directive 99-11-02. No cylinder head cracking was noted. ## Factual narrative On August 9, 2001, at 0900 central daylight time, an Air Tractor AT-401 agricultural airplane, N10140, was substantially damaged during a forced landing following a loss of engine power while maneuvering near Grand Coteau, Louisiana. The airplane was registered to Worthy Flying Service, Inc., of Gore Springs, Mississippi, and operated by Aerial Crop Care, Inc., of Port Barre, Louisiana. The commercial pilot, sole occupant, was not injured. Visual meteorological conditions prevailed, and a flight plan was not filed for the 14 Code of Federal Regulations Part 137 aerial application flight. The local flight originated from a private strip near Arnaudville, Louisiana, at 0845. According to the pilot, the airplane had completed a spray pass from south to north, and during a turn around maneuver, the "#4 jug blew." The pilot emptied the airplane's load and initiated a forced landing to a dirt road; however, the aircraft was unable to land on the road. The airplane touched down in a sweet potato field perpendicular to the rows with its right wing first. Subsequently, as the airplane touched down, its main landing gear collapsed. The airplane came to rest upright. Examination of the airplane by the FAA inspector, who responded to the accident site, revealed that the right main landing gear was separated, and the left main landing gear was folded aft. The fuselage at the right wing attach point was buckled, and the right wing tip was damaged. An examination of the engine revealed that the #4 cylinder head had fractured at the exhaust valve rocker arm boss. A review of the maintenance records revealed that on August 4, 2001 (4.4 hours prior to the accident), the Pratt & Whitney R-1340-AN-1 engine's cylinder heads were inspected for cracking in accordance with Airworthiness Directive 99-11-02. No cylinder head cracking was noted. ## Aircraft - Registration: [N10140](https://openairdocs.org/deregistered/N10140-2002-06-26), registration cancelled 2002-06-26, S/N 401-0732, built 1989 (OpenAirDocs) - Reported make and model: Air Tractor AT-401 - Registry model: [Air Tractor AT-401](https://openairdocs.org/model/air-tractor-at-401) (registry code 0390204) (OpenAirDocs) - Registry engine: [Pratt & Whitney R1340 series](https://openairdocs.org/engine/pratt-whitney-r1340-series) (registry code 52016, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 401-0732 - Airframe hours: 4280.3 - Engines: P&W R-1340-AN-1 600 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 137 - Airworthiness certificate: Special, Restricted (Special) - Last inspection: 100 hour, August 4, 2001, 4.4 hours before - Departed: NONE, Arnaudville, LA ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 39; injuries: none; commercial; airplane ratings: single-engine land; medical: class 2, valid medical--w/ waivers/lim; last flight review February 7, 2001; seat: center; flight hours: 2,600 total, 400 in this make and model, 2,500 as pilot in command ## Weather - Conditions: Visual (VMC), Day - Wind: 135° at 2 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 84 °F ## 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 20010809022709A](https://openairdocs.org/incident/20010809022709A), Aug 9, 2001: Airtrc AT401, Grandcoteau, LA, No damage. (-23) Pilot made one spray pass south to north. On second pass diving in ona north to south path, engine began shaking, spraying oil, backfiring and missing.… 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.