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Atlas / NTSB / WPR24LA262

NTSB CAROL · Event

Event WPR24LA262

2024-07-24 Bonners Ferry, Idaho, United States Airport · NONE None 1 aircraft Status: Completed

Registry · N3375T

FAA Aircraft Registry record.

Make / Model

HILLER UH-12E

TCDS

4H11 · SIAM HILLER HOLDINGS INC

Seats / Engines

4 seats · 1 engine

ADS-B equipped

Yes — Mode-S A3B2E9

Registrant of record

E L AUTOMATION INC

Source: FAA Aircraft Registry (releasable master file).

Aircraft involved

Probable cause & findings

The pilot’s improper selection of a landing site, which resulted in a main rotor strike. Contributing to the accident was the pilot’s improper performance planning and altitude selection over water, which resulted in an rpm droop.

Factual narrative

The pilot of the helicopter reported that with two passengers aboard, he approached a mountain lake to a hover above the water and saw the engine and rotor speed decrease to the green arc of the engine and rotor tachometer. He maneuvered the helicopter to the shore, and with the engine and rotor continuing to droop, he landed on some “substantially sized granite rocks” where the skids became lodged in the rocks. The helicopter then tipped forward and the main rotor blades impacted the rocks, which resulted in substantial damage to the main rotor and fuselage. The pilot reported there were no mechanical malfunctions or failures with the helicopter that would have precluded normal operation. The pilot added that he did not verify the performance capability for an in-ground effect or a hover out of ground effect over water. The Helicopter Flying Handbook, FAA-H-8083-21B, states, “When hovering over surfaces as tall grass, trees, bushes, rough terrain, and water, maximum ground effect is reduced.” 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).

  • Personnel issues-Task performance-Use of equip/info-Aircraft control-Pilot
  • Aircraft-Aircraft oper/perf/capability-Performance/control parameters-Powerplant parameters-Not attained/maintained
  • Aircraft-Aircraft oper/perf/capability-Performance/control parameters-Prop/rotor parameters-Not attained/maintained

Verbatim from NTSB's published report. Source file NTSB_2024_WPR24LA262.txt. Findings + structured fields enriched from FAA avall.mdb. Full investigation docket on data.ntsb.gov ↗.