[...] He planned to yaw left to align with the pontoon putting the wind further round. = reduction in right pedal to yaw left
When he attempted the go around, his yaw pedal position was very far behind where it needed to be and then he got weather-cocked to downwind and panicked. = needed enough right pedal to stop the original yaw and more to compensate for the handful of power pulled.
I don't know what Tq warning indications there are on the 120 but the Gazelle had a red flashing light that then went on steady.
In this respect I agree with Megan than concern about overTqing might have prevented him using full right pedal.
So instead of a mild overTq taking a couple of hours off the transmission - he crashed the aircraft instead!!!!! [emphasis by Hot and Hi]
The below has relevance:
Originally Posted by
Hot and Hi
[...] new civilian pilots are first and foremost taught to not over control and to avoid harsh, rapid or abrupt control inputs. [...]
When this yaw problem develops (ie in the hover, or when transitioning from slow forward flight to hover) we are (in a H120, Gazelle or Guimbal anyway) already close to max power. Again, pilots primary fear is to avoid over torquing that engine by commanding much of that power sapping Fenestron in the back.
From the actual
ATSB Transport Safety Report. Page 35:
Following the [mishap's] pilot’s check to line with the chief pilot on 13 March 2018, the chief pilot noted on the check form that the pilot needed to be gentle on the pedals [emphasis by Hot and Hi]. The chief pilot advised that all new EC120B pilots were coached the same way and the same comment could be found on many of the check ride records for those pilots.
Page 34:
(4) [...] If at this point [in OGE hover just before arriving overhead the pontoon - amended by Hot and Hi] the helicopter was at maximum take-off power, further application of right pedal would not be available (without exceeding engine limitations or ceasing the climb).
(5) The loss of airspeed experienced by a helicopter turning into a downwind position at low speed increases the power requirement[...]. If the use of right pedal was limited by the available power during the initial phase of the go-around, there would not be enough power for a recovery of the left yaw at this point without exceeding engine limitations.
Page 75
[...]there was a reduced power margin available to the pilot on the final approach to the pontoon. This was due to:
- The aircraft was overweight [[b]actually, above MTOW - amended by Hot and Hi] on departure from Hamilton Island. Being overweight on departure meant that when the pilot reached the pontoon the helicopter was heavier than it should have been. Although it was below the maximum allowable weight when operating at the pontoon, it was close to this maximum allowable weight.
- The helicopter’s engine power output was close to the lowest allowable limit for the helicopter type.
- The pilot was required to use high power to make a slow final approach in order to disperse birds from the pontoon.
And finally Page 77, confirming what crab said:
- The pilot reported keeping the power at or close to maximum take-off power during the go- around, and therefore they had limited power available to correct the yaw. As the helicopter kept yawing further left, it would have reached the point where applying sufficient right pedal to arrest the yaw and then yaw right would have meant exceeding engine limitations. Based on the available evidence, there were no indications an exceedance occurred after the go-around was initiated.