# NTSB CEN13LA239: Air Tractor AT-301, N23416, Bowling Green, MO, April 24, 2013 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: April 24, 2013, 16:10 local (21:10 UTC) - Place: Bowling Green, MO - Coordinates: 39.36972, -91.219169 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=39.3697&lon=-91.2192&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing-landing roll: Nose over/nose down](https://openairdocs.org/ntsb-events/096) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report December 11, 2013 - Report: Approved by Office Director - NTSB office: Central Region - Parties: FAA Flight Standards District Office - NTSB case key (mKey): 86723 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN13LA239 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/86723/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=86723 - Page: https://openairdocs.org/ntsb/CEN13LA239 ## Probable cause The failure of the engine supercharger's rear bearing, which resulted in the loss of engine power. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Turbocharging (recip only): turbocharger](https://openairdocs.org/ntsb-findings/01058120): Aircraft › Aircraft power plant · Failure (probable cause); cases with it: [Air Tractor AT-400A, 1 case](https://openairdocs.org/ntsb-findings/01058120/cases.md?model=0390203), [All aircraft, 29 cases](https://openairdocs.org/ntsb-findings/01058120/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Takeoff: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342); cases with it: [Air Tractor AT-400A, 1 case](https://openairdocs.org/ntsb-events/342/sequence.md?model=0390203), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) - [Landing-landing roll: Nose over/nose down](https://openairdocs.org/ntsb-events/096) (defining event); cases with it: [Air Tractor AT-400A, 1 case](https://openairdocs.org/ntsb-events/096/sequence.md?model=0390203), [All aircraft, 2,287 cases](https://openairdocs.org/ntsb-events/096/sequence.md) ## Analysis Shortly after takeoff, the engine lost power, and the pilot subsequently performed a forced landing to a field 1/4 mile off the departure end of the runway. During the forced landing, the airplane nosed over in the mud. According to the pilot, before takeoff, the engine was washed down, inspected, and then started and run for 15 minutes at idle power. The engine power was then advanced to 31 inches of manifold pressure. All engine checks were normal, and the engine ran smoothly. A postaccident examination of the engine revealed that the rear bearing in the supercharger had failed. Additional damage consistent with the failure of the rear bearing was noted throughout the supercharger and engine. An examination of the airframe, systems, and remaining engine sections revealed no mechanical malfunctions or failures that would have precluded normal operation. ## Factual narrative On April 24, 2013, about 1610 central daylight time, an Air Tractor Inc., AT-301 airplane, N23416, was substantially damaged during a forced landing near Bowling Green, Missouri. The commercial pilot was not injured. The airplane was registered to, and operated by Air Cover Crop Solutions LLC., under the provisions of 14 Code of Federal Regulations Part 91 without a flight plan. Visual meteorological conditions prevailed. The local flight was originating from the Bowling Green Municipal Airport (H19) at the time of the accident. According to the pilot, the engine was washed down, inspected, and then started and run for 15 minutes at idle power. The engine power was then advanced to 31 inches of manifold pressure; all engine checks were normal, and the engine ran smoothly. The pilot intended to change the engine oil after the flight. Shortly after takeoff, the engine lost power. The pilot performed a forced landing to a field 1/4 mile off of the departure end of the runway. During the forced landing, the airplane nosed over in the mud, and the wings and empennage were substantially damaged. During the examination of the engine, metal fragments were noted in the exhaust tubing. Further examination revealed that the rear bearing on the supercharger assembly had failed and was fragmented. Additional damage was noted to the middle and front bearings, the intermediate gear, the shaft seal, the cover plate, and the impeller. An examination of the airframe, systems, and remaining engine sections revealed no anomalies. ## Aircraft - Registration: [N23416](https://openairdocs.org/aircraft/N23416), registered now, S/N 301-0385, built 1981 (OpenAirDocs) - Reported make and model: AIR TRACTOR INC AT-301 - Registry model: [Air Tractor AT-400A](https://openairdocs.org/model/air-tractor-at-400a) (registry code 0390203) (OpenAirDocs) - Registry engine: [Pratt & Whitney PT6A-27 series](https://openairdocs.org/engine/pratt-whitney-pt6a-27-series) (registry code 52141, turbo-prop) (OpenAirDocs) - Category: Airplane - Serial number: 301-0385 - Airframe hours: 8865 - Engines: Pratt & Whitney R1340-S3H1-6 600 horsepower reciprocating - Damage: Substantial damage - Flight: Other work use, Part 91 - Operator: Air Cover Crop Solutions LLC - Registered owner: Air Cover Crop Solutions LLC - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, April 15, 2012 - Departed: H19, Bowling Green, MO - Destination: H19, Bowling Green, MO - Airport: H19, Bowling Green Municipal Airpor ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 47; injuries: none; airline transport, flight engineer, commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, with waivers/limitations; last flight review September 18, 2012; seat: single; flight hours: 14,000 total, 100 in this make and model, 12,000 as pilot in command, 100 in the last 90 days, 0 in the last 30 days, 0 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 260° at 10 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 52 °F, dew point 28 °F - Altimeter: 30.18 inHg - Observed at: KPPQ, 26 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 20130424012379A](https://openairdocs.org/incident/20130424012379A), Apr 24, 2013: Air Tractor Inc AT-301, Bowling Green, MO, Substantial damage. Amendment to original report: On July 25, 2013 the NTSB received a teardown report from covington aircraft in okmulgee, OK. The supercharger unit was sent to… ## Docket (4 files) The files NTSB released with the investigation on August 28, 2013, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=86723. 1.2 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 471 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40392449&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Record of Telephone Conversation - FAA Inspector (item 2, .PDF, 83 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40398157&FileExtension=.PDF&FileName=Record%20of%20Telephone%20Conversation%20-%20FAA%20Inspector-Master.PDF - Blower Examination Notes (item 3, .PDF, 185 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40398158&FileExtension=.PDF&FileName=Blower%20Examination%20Notes-Master.PDF - Statement of Party Representatives to NTSB Investigation (item 4, .PDF, 415 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40398209&FileExtension=.PDF&FileName=Statement%20of%20Party%20Representatives%20to%20NTSB%20Investigation-Redacted.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.