- Date
- July 24, 2024, 07:30 local (14:30 UTC)
- Place
- Bonners Ferry, ID · Lakeshore
- Injuries
- 3 uninjured
- Damage
- Substantial damage
- Phase of flight
- Landing
- Aircraft
- N3375THiller UH-12E
- Defining event
- Landing: Loss of control in flight
- Weather
- Visual (VMC) · Day
- Status
- Completed
- Report
- Approved by Office Director
- Investigation class
- Class 4 - Basic report with no Prelim publish
- NTSB office
- Western Pacific Region
- Parties
- Federal Aviation Administration
- FAA report
- 20240724009899A
- Case key
- 194811
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.
On this page
Probable cause
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.
Findings · 3
NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.
Sequence of events
The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.
Analysis
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.”
Aircraft
- Registration
- N3375T
- Reported as
- Hiller UH-12E
- Category
- Helicopter
- Serial number
- 5237
- Built
- 2001
- Airframe hours
- 425.9
- Engine
- Lycoming VO540C2A, 305 horsepower, reciprocating
- Damage
- Substantial damage
- Flight
- Personal · Part 91
- Airworthiness certificate
- Standard, Normal
- Last inspection
- Annual · October 24, 2023 · 35 hours before
- Departed
- Priv · Bonners Ferry, ID
- Airport
- None
- Equipment
- ADS-B, Handheld GPS
Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.
Flight crew
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 66
- Injuries
- None
- Certificate
- Private
- Medical
- Class 3, Without waivers/limitations
- Last flight review
- August 24, 2023
- Seat
- Center
- Restraint
- 3-point
- Flight hours
- 349 total · 272 in this make and model · 281 as pilot in command
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- Calm
- Visibility
- 10 statute miles
- Lowest ceiling
- None
- Temperature
- 61 °F, dew point 41 °F
- Altimeter
- 30.06 inHg
- Observed at
- K65S, 13 nm away
- METAR
- K65S 241435Z AUTO 00000KT 10SM CLR 16/05 A3006 RMK AO2
Docket · 2
The files NTSB released with the investigation on March 6, 2025, on NTSB’s docket system: statements, records, photos and specialists’ reports. 5.2 MB in all.
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.