The ATSB this week issued a warning about type recency after the crash of an EC120B at Porepunkah, Vic, in May this year.
VH-JDZ had lifted off from Porepunkah airstrip on a passenger flight to Albury, when the aircraft entered an uncommanded yaw to the left after entering a hover.
The aircraft rotated through 180o before the pilot attempted to correct the yaw with right rudder, but it was insufficient to stop the turn and the right skid struck the ground leading to a rollover and substantial damage. The two people on board were able to evacuate without injury.
ATSB investigators found that the pilot was a highly-experienced helicopter pilot who was endorsed for the EC120, but hadn't flown the type for around 15 years.
"The EC120’s ‘Fenestron’ shrouded tail rotor requires greater pedal response than conventional tail rotors such as those on helicopters like the Robinson R44, which the pilot had primarily flown in the 12 months prior to the accident,” ATSB Director Transport Safety Stuart Godley noted.
“Although a highly experienced helicopter pilot, the pilot’s lack of recent type experience on the EC120 degraded their ability to anticipate and counter the left yaw."
After power is applied, the EC120 yaws to the left not to the right like the R44 and requires a larger opposite pedal input to arrest yaw.
“Being highly experienced flying helicopters, this likely increased the pilot’s perception of their ability to operate the EC120, even though they had not operated the aircraft type for several years,” Godley noted.
“This highlights the importance of maintaining recent type‑specific flight experience when transitioning between aircraft with differing control characteristics, and maintaining an understanding of the specific characteristics of the aircraft you fly.”
In 2005, Eurocopter–now Airbus Helicopters–released a service letter reminding pilots that Fenestron tail rotors required significantly more pedal travel than conventional tail rotors when transitioning from forward flight to a hover.
Investigations found similar accidents with EC120s occurred at Mansfield in Victoria in 2019 and Ballina NSW in 2013.
The full investigation report is on the ATSB website.