- Date
- August 30, 2024, 07:05 local (14:05 UTC)
- Place
- Colusa, CA
- Injuries
- 1 serious
- Damage
- Substantial damage
- Phase of flight
- Maneuvering
- Aircraft
- N710WDWilliams Helicopter UH-1H
- Defining event
- Maneuvering-hover: 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
- Case key
- 195085
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 failure to set collective friction which resulted in collective bounce and subsequent loss of control.
Findings · 2
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 while repositioning closer to the loading equipment, the helicopter experienced collective bounce. He attempted to maneuver the helicopter to avoid equipment and personnel; however, control was lost and the helicopter impacted terrain. The operator reported that there were no preaccident mechanical malfunctions or failures that would have precluded normal operations. The operators manual for the helicopter stated, in part, “Collective bounce is a pilot Induced vertical oscillation of the collective control system when an absolute friction (either pilot applied, or control rigged) is less than seven pounds. It may be encountered in any flight condition by a rapid buildup of vertical bounce at approximately three cycles per second. The seventy of the oscillation is such that effective control of the helicopter may become difficult to maintain. The pilot should apply and maintain adequate collective friction in all flight conditions.”
Aircraft
- Registration
- N710WD
- Reported as
- Williams Helicopter UH-1H
- Category
- Helicopter
- Serial number
- 65-09761
- Built
- 1965
- Engine
- Ozark-Aeroworks T53-L-13B, 1,318 horsepower, turbo shaft
- Damage
- Substantial damage
- Flight
- Aerial application · Part 137
- Operator
- A&P Helicopters Inc
- Registered owner
- A&P Helicopters Inc
- Airworthiness certificate
- Special, Restricted (Special)
- Departed
- 07CL · Richvale, CA
- Airport
- none
- Equipment
- ADS-B, Satellite tracking device
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
- 60
- Injuries
- Serious
- Certificate
- Commercial
- Airplane ratings
- Multi-engine land, Single-engine sea, Single-engine land
- Instrument ratings
- Airplane
- Medical
- Class 2, Without waivers/limitations
- Last flight review
- October 11, 2023
- Seat
- Right
- Restraint
- 4-point
- Flight hours
- 13,000 total · 22 in this make and model · 13,000 as pilot in command · 125 in the last 90 days · 50 in the last 30 days · 1 in the last 24 hours
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 130° at 3 knots
- Visibility
- 10 statute miles
- Lowest ceiling
- None
- Temperature
- 70 °F, dew point 54 °F
- Altimeter
- 30.01 inHg
- Observed at
- KOVE, 23 nm away
- METAR
- METAR KOVE 301453Z AUTO 13003KT 10SM CLR 21/12 A3001 RMK AO2 SLP162 T02060122 53013=
Docket · 4
The files NTSB released with the investigation on April 22, 2025, on NTSB’s docket system: statements, records, photos and specialists’ reports. 4.8 MB in all.
Other investigations on N710WD · 1
Matched to the same aircraft by N-number and date.