Robinson R44 N144KW

Summary

On 11 July 2024 at about 23:05 local time, a Robinson R44 registered N144KW, operated by Ali’i Air Tours, was involved in an accident near Kekaha, Hawaii, United States. 3 people were on board and 3 died. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

11 July 2024 at 23:05

Classification

Accident

Location

Kekaha, Hawaii, United States

Coordinates

22.1836, -159.6460

Aircraft

Robinson R44

Registration

N144KW

Category

Helicopter

Year built

2009

Engines

1

Operator

Ali’i Air Tours

Operating rule

Part 91: General Aviation

Purpose of flight

Aerial Observation

Phase of flight

Not recorded

Route

Lihue → Unknown

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

ANC24FA063

3 people died.

An encounter with turbulence due to downdraft winds that resulted in mast bumping and an in-flight breakup.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

The helicopter was on a local air tour when the accident occurred. Witnesses reported strong, gusting wind and that a “huge” and sudden gust of wind blew over them, which was followed by a very loud “bang” noise. As their attention was drawn to the source of the loud noise, they saw the helicopter wreckage freefalling into the ocean in two sections: a main fuselage section and the tail boom section. Examination of the wreckage revealed no evidence of any preexisting anomalies that would have precluded normal operation of the helicopter. There was evidence that a mast bumping event had occurred and that the main rotor blades had contacted the airframe, which resulted in an in-flight breakup. There was no recorded information available that could be used to determine the helicopter's airspeed, altitude, or the pilot's control inputs. A weather study indicated that conditions were conducive to the development of strong downdraft winds. It is likely that the helicopter encountered turbulence due to downdrafts, which resulted in mast bumping and a subsequent in-flight breakup. Robinson Safety Notice SN-32 discusses flight in high winds and turbulence and explains how improper application of control inputs in response to turbulence can increase the likelihood of a mast bumping accident. It recommends that pilots reduce airspeed below normal cruise speed to 60 to 70 knots for flight in significant turbulence. It suggests techniques to avoid overcontrol of the helicopter and says to avoid flying on the downwind side of hills and ridges.

Quoted verbatim from the NTSB record.