# NTSB FTW97LA169: Air Tractor AT-400, N73127, Fluvanna, TX, April 19, 1997 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: April 19, 1997, 14:00 local (19:00 UTC) - Place: Fluvanna, TX - Coordinates: 32.890659, -101.150459 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=32.8907&lon=-101.1505&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report August 25, 1997 - Report: Approved by Office Director - NTSB case key (mKey): 20204 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW97LA169 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/20204/pdf - Page: https://openairdocs.org/ntsb/FTW97LA169 ## Probable cause The loss of engine power due to the failure of the reduction gear box. 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 - reduction gear assy - failure,total (cause) - turbine assembly,shaft bearing - sheared - turbine assembly - overspeed - turbine assembly,turbine blade - disintegrated - Forced landing, emergency descent/landing - In flight collision with terrain/water, emergency landing - terrain condition - none suitable (contributing factor) - terrain condition - rough/uneven ## Analysis The pilot was performing a swath run when he felt a vibration, and then the engine lost power. A forced landing was initiated to a plowed field. During the landing sequence, the left main landing gear separated from the fuselage, and the right wing spar was bent upward. A teardown inspection of the airplane's engine revealed that the reduction gear box failed and sheared the drive shaft. According to the FAA inspector, 'This failure allowed a turbine over speed to the point that the turbine blades separated from the wheel causing a contained catastrophic failure.' ## Factual narrative On April 19, 1997, at 1400 central daylight time, an Air Tractor AT-400 agricultural airplane, N73127, registered to and operated by Benny White Flying Service, Inc., as a Title 14 CFR Part 137 aerial application flight, was substantially damaged during a forced landing following a loss of engine power near Fluvanna, Texas. The commercial pilot was not injured. Visual meteorological conditions prevailed, and a flight plan was not filed for the local flight that originated from a private airstrip near Lamesa, Texas. According to the pilot, he was performing a swath run when he felt a vibration, followed by a loss of engine power. A forced landing was initiated to a plowed field. During the landing sequence, the left main landing gear separated from the fuselage, and the right wing spar was bent upward. Examination of the PT6A-27 engine by a mechanic and the FAA inspector revealed that the turbine disc was missing approximately half of its blades. The engine was sent to Dallas Airmotive in Dallas, Texas, for further examination. On May 22, 1997, a teardown inspection revealed that the reduction gear box failed and sheared the drive shaft. According to the FAA inspector, "It was impossible to determine which part failed first. This failure allowed a turbine over speed to the point that the turbine blades separated from the wheel causing a contained catastrophic failure." According to the operator, the engine had accumulated a total of 2,430 hours since new, with approximately 1,300 hours since last overhaul. ## Aircraft - Registration: [N73127](https://openairdocs.org/aircraft/N73127), registered now, S/N 301-0667, built 1987 (OpenAirDocs) - Reported make and model: Air Tractor AT-400 - Registry model: [Air Tractor AT-400A](https://openairdocs.org/model/air-tractor-at-400a) (registry code 0390203) (OpenAirDocs) - Registry engine: [Pratt & Whitney Canada PT6A-20](https://openairdocs.org/engine/pratt-whitney-canada-pt6a-20) (registry code 52239, turbo-prop) (OpenAirDocs) - Category: Airplane - Serial number: 301-0667 - Airframe hours: 3562 - Engines: P&W PT6A-27 680 horsepower turbo prop - Damage: Substantial damage - Flight: Aerial application, Part 137 - Registered owner: Benny White Flying Svc Inc - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, March 3, 1997, 86 hours before - Departed: NONE, LAMESA, TX ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 44; commercial; airplane ratings: single-engine land; medical: class 2, valid medical--w/ waivers/lim; seat: front; flight hours: 10,000 total, 320 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: 2,300 ft overcast - Temperature: 63 °F, dew point 54 °F - Altimeter: 29.00 inHg - Observed at: ABI, 157 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 19970419007399A](https://openairdocs.org/incident/19970419007399A), Apr 19, 1997: Airtrc AT301, Fluvanna, TX, Substantial damage. Rough engine power loss on a swath run. Tore off gear bent wing landing. Remote gear box failed. Broke shaft blades (-23) see attached sheet; no narrative… ## Other investigations on N73127 (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 FTW88DQG02](https://openairdocs.org/ntsb/FTW88DQG02), Oct 19, 1987: Air Tractor AT-301 (N73127), Lockney, TX, 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.