Slow Down When Encountering Turbulence - the Robbies Don't Appreciate Rough Handling

The Australian Transport Safety Bureau released a preliminary report on an in-flight breakup of a Robinson Helicopters R66 that took place in October of 2023, providing advice for turbulent operations in the wake of their ongoing investigation.

After reviewing the data and investigating the wreckage, the ATSB has advised helicopter pilots to take some caution when encountering turbulence. Recognizing a low-g condition, slowing down to maneuvering speed, and taking it easy can lessen the stresses imposed on a light aircraft - and that wariness might have saved a life last October. The Aussies cite a pair of Robinson Helicopter Safety Notices, SN-11 and SN-32, that describe the increased likelihood of mast bumping and in-flight breakup when tackling turbulent conditions above maneuvering speed.

The in-flight breakup of the aircraft took place during a VFR flight along the coast, which began in apparent normalcy only to end in the abrupt and unforeseen structural failure of the aircraft, killing all aboard. Thankfully, investigators were handed over a roof panel of the aircraft that contained its recording system, giving them a perfect view of the entire flight with audio and GPS positions included.

“The helicopter’s onboard video camera showed at this time that the helicopter’s autopilot was engaged, with heading hold and altitude mode selected,” ATSB Chief Commissioner Angus Mitchell said. As the helicopter passed north of Yacaaba Headland and over Providence Bay it rolled left slightly, then right and left to bank angles of about 10 to 15 degrees. During this time, the nose remained pitched up at about 6 degrees and the helicopter climbed to about 1,100 ft AMSL."

From there, things got dicey, he added. "The helicopter’s nose pitched down and it rolled to the right, becoming completely inverted, and continuing to roll right to about 270 degrees.” Investigators now believe that during the accident sequence, the main rotor impacted the cabin, hitting and separating the tail boom aft of the engine fairing. Stricken, the Robinson R66 fell straight into the waters below, fatally injuring the PIC.

To prevent similar occurrences in a Robinson aircraft, the ATSB says that turbulence should be avoided where possible, and if unavoidable, passed through at a speed between 60 and 70 knots in accordance with the company's Safety Notice 32.

FMI: www.atsb.gov.au