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Atlas / NTSB / WPR11CA398

NTSB CAROL · Event

Event WPR11CA398

2011-08-21 Los Banos, California, United States Airport · KLSN Minor 1 aircraft Status: Completed

Aircraft involved

Probable cause & findings

The pilot's failure to maintain clearance from the power poles while maneuvering during low-altitude operations.

Factual narrative

The pilot was performing an agricultural application flight in the helicopter over a cantaloupe field. During the final pass along the field border, he observed bee boxes adjacent to power poles, and he shut off the spray applicator. After passing the boxes, he turned the spray applicator back on; his next recollection was of lying upside down in the field. Examination of the helicopter at the accident site revealed that the main rotor blades struck a set of wooden power poles at the 20-foot-level. The helicopter sustained substantial damage to the main rotor blades and fuselage structure. The pilot reported that he had flown an application flight over the same field a week prior, and was aware of the location of the power poles. The pilot reported no preimpact mechanical malfunctions or failures with the airframe or engine that would have precluded normal operation. The pilot was performing an agricultural application flight in the helicopter over a cantaloupe field. During the final pass along the field border, he observed bee boxes adjacent to power poles, and he shut off the spray applicator. After passing the boxes, he turned the spray applicator back on; his next recollection was of lying upside down in the field. Examination of the helicopter at the accident site revealed that the main rotor blades struck a set of wooden power poles at the 20-foot-level. The helicopter sustained substantial damage to the main rotor blades and fuselage structure. The pilot reported that he had flown an application flight over the same field a week prior, and was aware of the location of the power poles. The pilot reported no preimpact mechanical malfunctions or failures with the airframe or engine that would have precluded normal operation. Source: NTSB Aviation Accident Database Retrieved: 2026-02-12

NTSB Findings

Hierarchical cause / factor breakdown from the FAA bulk avdata database. Each finding tagged C (Cause) or F (Factor).

  • C Personnel issues-Psychological-Attention/monitoring-Task monitoring/vigilance-Pilot - C
  • C Environmental issues-Physical environment-Object/animal/substance-Pole-Response/compensation - C

Verbatim from NTSB's published report. Source file NTSB_2011_WPR11CA398.txt. Findings + structured fields enriched from FAA avall.mdb. Full investigation docket on data.ntsb.gov ↗.