# NTSB FTW97LA321: Air Tractor AT-400, N3654G, Sudan, TX, August 25, 1997 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: August 25, 1997, 12:30 local (17:30 UTC) - Place: Sudan, TX - Coordinates: 34.060611, -102.520744 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=34.0606&lon=-102.5207&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report April 24, 1998 - Report: Approved by Office Director - NTSB case key (mKey): 20322 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW97LA321 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/20322/pdf - Page: https://openairdocs.org/ntsb/FTW97LA321 ## Probable cause The loss of engine power due to the failure of a compressor turbine blade. A 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 - turbine assembly,turbine blade - failure (cause) - Forced landing, emergency descent/landing - On ground/water encounter with terrain/water, emergency landing - terrain condition - rough/uneven - terrain condition - none suitable (contributing factor) ## Analysis During the aerial application flight, the engine of the agricultural airplane lost power, and the pilot executed a forced landing in a cotton field. During the ground roll across the furrows in the field, the left main wheel separated from the landing gear leg, and subsequently, the right main landing gear leg separated from the fuselage. Examination of the engine revealed that a blade failure at the compressor turbine disk had occurred resulting in extensive damage to the hot section of the engine and the complete loss of engine power. ## Factual narrative On August 25, 1997, approximately 1230 central daylight time, an Air Tractor AT-400 agricultural airplane, N3654G, registered to and operated by King Ag Aviation, sustained substantial damage during a forced landing following a loss of engine power near Sudan, Texas. The commercial pilot, the sole occupant, was not injured. No flight plan was filed and visual meteorological conditions prevailed for the Title 14 CFR Part 137 local aerial application flight. In a written statement provided to the investigator-in-charge, the pilot reported that "the motor blew up," and he was forced to land the airplane in a field "going across" the furrows. During the ground roll, the left main wheel separated from the landing gear leg, the airplane "got sideways," and the right main landing gear leg then separated from the fuselage. The FAA inspector who examined the accident site reported that the airplane touched down in a cotton field and rolled about 400 to 500 feet across the furrows before coming to rest in an upright position. He further reported that the fuselage forward of the tail section was twisted. On September 9, 1997, the engine, a Pratt & Whitney PT6A-20, S/N PCE 22438, was examined under the supervision of a FAA inspector at Dallas Airmotive, Inc., in Dallas, Texas. According to the FAA inspector, "the engine experienced blade failure at the Compressor Turbine disk" resulting in "extensive damage to the hot section of the engine." The inspector reported that his review of the engine maintenance records indicated the blades had 11,381.6 hours total time in service. He further reported that "the blades still had some time left in accordance with the manufacturer's specifications." ## Aircraft - Registration: [N3654G](https://openairdocs.org/aircraft/N3654G), registered now, S/N 400-0281 (OpenAirDocs) - Reported make and model: Air Tractor AT-400 - Registry model: [Air Tractor AT-400](https://openairdocs.org/model/air-tractor-at-400) (registry code 0390202) (OpenAirDocs) - Category: Airplane - Serial number: 400-0281 - Engines: P&W PT6A-20 550 horsepower turbo prop - Damage: Substantial damage - Flight: Aerial application, Part 137 - Registered owner: King Ag Aviation - Airworthiness certificate: Special, Restricted (Special) ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 27; private, commercial; airplane ratings: multi-engine land, single-engine sea, single-engine land; instrument ratings: airplane; medical: class 2, invalid medical for flight; seat: center; flight hours: 3,000 total, 2,000 in this make and model, 2,600 as pilot in command, 300 in the last 90 days ## Weather - Conditions: Visual (VMC), Day - Lowest ceiling: none ## 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 19970825024229A](https://openairdocs.org/incident/19970825024229A), Aug 25, 1997: Airtrc AT400, Sudan, TX, Substantial damage. Aircraft engine failed during aerial application, made emergency landing. (-23) engine failure during approach into field for spray pass. 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.