# NTSB GAA18CA309: Air Tractor AT 402, N5128N, Nicolaus, CA, May 19, 2018 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: May 19, 2018, 09:45 local (16:45 UTC) - Place: Nicolaus, CA - Coordinates: 38.932777, -121.496665 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=38.9328&lon=-121.4967&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-low-alt flying: Low altitude operation/event](https://openairdocs.org/ntsb-events/220) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report October 24, 2018 - Report: Approved by Office Director - NTSB office: General Aviation Accidents - Parties: FAA - NTSB case key (mKey): 97348 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=GAA18CA309 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/97348/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=97348 - Page: https://openairdocs.org/ntsb/GAA18CA309 ## Probable cause The pilot’s failure to maintain adequate clearance from a power transmission wire. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Performance/control parameters: pitch control](https://openairdocs.org/ntsb-findings/01062022): Aircraft › Aircraft oper/perf/capability · Incorrect use/operation (probable cause); cases with it: [Air Tractor AT-402A, 1 case](https://openairdocs.org/ntsb-findings/01062022/cases.md?model=0390206), [All aircraft, 526 cases](https://openairdocs.org/ntsb-findings/01062022/cases.md) - [Attention/monitoring: monitoring environment](https://openairdocs.org/ntsb-findings/02021545): Personnel issues › Psychological · Pilot (probable cause); cases with it: [Air Tractor AT-402A, 3 cases](https://openairdocs.org/ntsb-findings/02021545/cases.md?model=0390206), [All aircraft, 809 cases](https://openairdocs.org/ntsb-findings/02021545/cases.md) - [Object/animal/substance: wire](https://openairdocs.org/ntsb-findings/03022032): Environmental issues › Physical environment · Effect on operation (probable cause); cases with it: [Air Tractor AT-402A, 1 case](https://openairdocs.org/ntsb-findings/03022032/cases.md?model=0390206), [All aircraft, 588 cases](https://openairdocs.org/ntsb-findings/03022032/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: Attempted remediation/recovery](https://openairdocs.org/ntsb-events/060); cases with it: [Air Tractor AT-402A, 2 cases](https://openairdocs.org/ntsb-events/060/sequence.md?model=0390206), [All aircraft, 1,422 cases](https://openairdocs.org/ntsb-events/060/sequence.md) - [Maneuvering-low-alt flying: Low altitude operation/event](https://openairdocs.org/ntsb-events/220) (defining event); cases with it: [Air Tractor AT-402A, 3 cases](https://openairdocs.org/ntsb-events/220/sequence.md?model=0390206), [All aircraft, 780 cases](https://openairdocs.org/ntsb-events/220/sequence.md) ## Analysis The pilot reported that, during an agricultural application flight, he observed a power transmission wire with no obstructions underneath. He added that he turned around to enter the spray field under the wire, where he observed one wire sagging lower than the other wires. While flying under the power transmission wire, the airplane encountered turbulence, so he decided to lower the nose to prevent being pushed into the wire. However, the tail rose up and struck the power transmission wire. The airplane sustained substantial damage to the vertical stabilizer and rudder. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation. The pilot reported that the wind was calm. ## Factual narrative The pilot reported that, during an aerial application flight, he observed a power transmission wire with no obstructions underneath. He added that he turned around to enter the spray field under the wire, where he observed one wire sagging lower than the other wires. While flying under the power transmission wire, he encountered turbulence, and decided to lower the nose to prevent being pushed into the wire. The tail went up and struck the power transmission wire. The airplane sustained substantial damage to the vertical stabilizer and rudder. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation. The pilot reported in the NTSB 6120.1 Form that the wind was calm. ## Aircraft - Registration: [N5128N](https://openairdocs.org/aircraft/N5128N), registered now, S/N 402A-1054, built 1998 (OpenAirDocs) - Reported make and model: AIR TRACTOR INC AT 402 (A) - Registry model: [Air Tractor AT-402A](https://openairdocs.org/model/air-tractor-at-402a) (registry code 0390206) (OpenAirDocs) - Registry engine: [Pratt & Whitney PT6A series](https://openairdocs.org/engine/pratt-whitney-pt6a-series) (registry code 52034, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 402A-1054 - Year built: 1998 - Airframe hours: 5133 - Engines: P&W Canada PT6-11AG 550 horsepower turbo prop - Damage: Substantial damage - Flight: Aerial application, Part 137 - Operator: Arena Pesticide Management Inc - Registered owner: Arena Pesticide Management Inc - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, December 1, 2017 - Departed: PVT, Knights Landing, CA - Equipment: Stall warning system ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 69; injuries: none; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review December 27, 2017; seat: single; restraint: 4-point; flight hours: 33,252 total, 631 in this make and model, 136 in the last 90 days, 105 in the last 30 days, 7 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 150° at 10 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 63 °F, dew point 50 °F - Altimeter: 29.90 inHg - Observed at: KLHM, 7 nm away ## Docket (2 files) The files NTSB released with the investigation on August 28, 2018, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=97348. 3.8 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 3.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40466114&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Accident Photos (item 2, .PDF, 2 photos, 240 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40466115&FileExtension=.PDF&FileName=Accident%20Photos-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.