# NTSB CEN12LA589: Air Tractor AT-301, N23960, Ralls, TX, August 29, 2012 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: August 29, 2012, 15:30 local (20:30 UTC) - Place: Ralls, TX - Coordinates: 33.607776, -101.323608 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=33.6078&lon=-101.3236&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-low-alt flying: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed, report October 9, 2014 - Report: Approved by Office Director - NTSB office: Central Region - Parties: FAA Lubbock FSDO - NTSB case key (mKey): 84855 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN12LA589 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/84855/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=84855 - Page: https://openairdocs.org/ntsb/CEN12LA589 ## Probable cause The total loss of engine power due to a fatigue failure of the rocker arm journal casting of the rocker arm cap. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine (reciprocating): recip eng cyl section](https://openairdocs.org/ntsb-findings/01058530): Aircraft › Aircraft power plant · Fatigue/wear/corrosion (probable cause); cases with it: [Air Tractor AT-301, 6 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md?model=0390103), [All aircraft, 373 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering-low-alt flying: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) (defining event); cases with it: [Air Tractor AT-301, 5 cases](https://openairdocs.org/ntsb-events/340/sequence.md?model=0390103), [All aircraft, 820 cases](https://openairdocs.org/ntsb-events/340/sequence.md) - [Emergency descent: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Air Tractor AT-301, 19 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=0390103), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing: Nose over/nose down](https://openairdocs.org/ntsb-events/096); cases with it: [Air Tractor AT-301, 6 cases](https://openairdocs.org/ntsb-events/096/sequence.md?model=0390103), [All aircraft, 2,287 cases](https://openairdocs.org/ntsb-events/096/sequence.md) ## Analysis The pilot reported that, while conducting aerial application operations, the engine sputtered and then experienced a complete loss of power. During the forced landing, the airplane nosed over and then came to rest inverted. A postaccident examination of the engine revealed a fatigue failure of the rocker arm journal casting of the rocker arm cap, which resulted in the complete separation of the rocker arm and failure of the exhaust valve. ## Factual narrative On August 29, 2012, about 1530 central daylight time, an Air Tractor, Inc. AT-301 airplane, N23960, was substantially damaged after impacting terrain during a forced landing near Ralls, Texas. The pilot was not injured. The airplane was registered to and operated by Beta Ag, Inc., under the provisions of 14 Code of Federal Regulations Part 137, as an agricultural application flight. Day visual meteorological conditions prevailed and no flight plan was filed. The airplane was on a local flight and had departed about 1515 from Crosbyton Municipal Airport, (8F3), Crosbyton, Texas.The pilot reported that the engine sputtered and he then experienced a complete loss of engine power. During the power-off landing to a soft dirt trail in a cotton field the airplane nosed-over, and came to rest inverted. The pilot was able to exit without assistance. There was a substantial amount of fuel on-board, but no fuel spill and no postimpact fire. A postaccident examination of the Pratt and Whitney R-1340 engine, serial number P 326932, revealed there was a fatigue failure of the rocker arm journal casting of the rocker arm cap, which resulted in the complete separation of the exhaust valve rocker arm. ## Aircraft - Registration: [N23960](https://openairdocs.org/deregistered/N23960-2016-01-19), registration cancelled 2016-01-19, S/N 301-0448, built 1982 (OpenAirDocs) - Reported make and model: AIR TRACTOR INC AT-301 - Registry model: [Air Tractor AT-301](https://openairdocs.org/model/air-tractor-at-301) (registry code 0390103) (OpenAirDocs) - Registry engine: [Pratt & Whitney R1340 series](https://openairdocs.org/engine/pratt-whitney-r1340-series) (registry code 52016, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 301-0448 - Airframe hours: 10294 - Engines: P&W R-1340 AN-1 600 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 137 - Operator: Beta Ag Inc, doing business as Beta Ag Inc - Registered owner: Beta Ag Inc - Airworthiness certificate: Special, Restricted (Special) - Departed: 8F3, Crosbyton, TX - Destination: 8F3, Crosbyton, TX ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 42; injuries: none; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review May 21, 2012; seat: single; restraint: 4-point; flight hours: 702 total, 239 in this make and model, 218 in the last 90 days, 50 in the last 30 days, 4 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: variable at 3 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 88 °F, dew point 43 °F - Altimeter: 30.01 inHg - Observed at: KLBB, 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 20120829017199A](https://openairdocs.org/incident/20120829017199A), Aug 29, 2012: Air Tractor Inc AT-301, Ralls, TX, Substantial damage. Approximatly 1530 CDT on August 29, 2012, the pilot was performing aerial applications of a cotton field with herbicides (roundup). He took off from crosbyton… ## Docket (4 files) The files NTSB released with the investigation on September 11, 2014, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=84855. 3.6 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 402 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40416390&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Maps (item 2, .PDF, 211 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40416391&FileExtension=.PDF&FileName=Maps-Master.PDF - Photo 1 - Wreckage (Photo Courtesy of FAA) (item 3, .PDF, 1.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40416392&FileExtension=.PDF&FileName=Photo%201%20-%20Wreckage%20(Photo%20Courtesy%20of%20FAA)-Master.PDF - Photo 2 - Close-up View of Wreckage (Photo Courtesy of FAA) (item 4, .PDF, 1.9 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40416393&FileExtension=.PDF&FileName=Photo%202%20-%20Close-up%20View%20of%20Wreckage%20(Photo%20Courtesy%20of%20FAA)-Master.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.