- Date
- February 19, 2018
- Place
- Pacific Ocean, Marshall Islands
- Injuries
- 2 minor
- Damage
- Substantial damage
- Phase of flight
- Maneuvering
- Aircraft
- N501VSHughes 369D
- Defining event
- Maneuvering-low-alt flying: Unknown or undetermined
- Weather
- Visual (VMC) · Day
- Status
- Completed · report June 29, 2020
- Report
- Approved by Office Director
- NTSB office
- Western Pacific Region
- Parties
- Federal Aviation Administration
- Case key
- 96831
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
An in-flight mechanical malfunction with the helicopter, which necessitated a ditching in the ocean. The reason for the malfunction could be determined because the helicopter sank and was not recovered.
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 departed for a flight over the open ocean. About 1 hour into the flight, the pilot descended the helicopter to sea level to attach a GPS buoy to a log. After attaching the buoy and as the helicopter was climbing through 400 to 500 ft above the water, the pilot heard a bang come from the area of the rotor head, followed by the cyclic control shaking. The pilot contacted support vessel personnel, notified them of the issue, and proceeded in the vessel's direction, but the helicopter continued experiencing intermittent flight control problems and was unable to reach the vessel. The pilot attempted to deploy the inflatable floats; however, they did not deploy. The pilot subsequently initiated a ditching, and the helicopter impacted water and rolled inverted. The pilot and passenger egressed the helicopter, which then sank, and the helicopter was not recovered.
Factual narrative
The pilot and passenger departed on a fish survey flight over the open ocean. About an hour into the flight, a descent was made to sea level to attach a GPS buoy on a log. After attaching the buoy, the helicopter was climbing through 400-500 ft, when the pilot heard a bang come from the area of the rotor head, followed by a shake in the cyclic control. The pilot radioed the support vessel notifying them of the issue and proceeded to head in their direction. The pilot continued to experience intermittent flight control problems, and unable to reach the vessel, attempted to deploy the inflatable floats, however they did not deploy. The pilot subsequently declared a mayday and initiated a forced water landing. After the helicopter impacted the water, it rolled inverted. The pilot and passenger egressed before the helicopter sank. The helicopter was not recovered.
Aircraft
- Registration
- N501VS
- Reported as
- Hughes 369D (D)
- Category
- Helicopter
- Serial number
- 170050D
- Built
- 1977
- Airframe hours
- 18,502.5
- Engine
- Rolls Royce 250-C20B, 420 horsepower, turbo shaft
- Damage
- Substantial damage
- Flight
- Aerial observation · Part 91
- Airworthiness certificate
- Standard, Normal
- Last inspection
- 100 hour · December 19, 2017 · 79 hours before
- Departed
- Marshall Island
- Destination
- Marshall Islands
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
- 26
- Injuries
- Minor
- Certificate
- Commercial
- Medical
- Class 2, With waivers/limitations
- Seat
- Left
- Restraint
- 4-point
- Flight hours
- 0 total · 0 in this make and model
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 270° at 10 knots
- Visibility
- 10 statute miles
- Lowest ceiling
- None
- Temperature
- 88 °F
Docket · 2
The files NTSB released with the investigation on April 20, 2018, on NTSB’s docket system: statements, records, photos and specialists’ reports. 2.9 MB in all.