Originally Posted by
Ascend Charlie
Remember that in the AS350, a sharp control movement can defeat the hydraulics and make the cyclic lock up momentarily. The aircraft can roll rapidly under such conditions.
I disagree slightly.
In my experience for what it is worth.
High G will do it. Rapid control movement, not so much.
The controls do not “Freeze” or “Lock Up” you feel feedback but the controls are still fully effective albeit with additional force required.
In the 350D the flight manual states that, if encountered, you have reached the G limit of the airframe.
On the 355, due to the dual hydraulic system, this is indicated by the illumination of the “Limit” light on the caution panel.
In both cases you have reached the “G limit” of the helicopter so are doing something you shouldn’t. Decreasing power, angle of bank or back pressure on the cyclic [ or combination thereof ] will solve the problem.
We used to demonstrate this during training.
As to rapid roll…turning the hydraulics off using the push switch on the collective will lead to an exiting pitch up and rapid right roll especially ar higher speeds.
We also demonstrated this very carefully at slower speeds.
Training was done after a full briefing on the system, symptoms to expect and proper actions for recovery, .rebriefed in the air and done carefully. Not something you would “surprise” somebody with.
An actual hydraulic failure with empty accumulators would lead to the same result of a rapid climbing roll which will get your undivided attention. We had a lot of hydraulic problems when the 350 came on the market. Immediate Actions included: “HORN….. OFF so you can think!”
I have never flown a B.
Flying a 350 with no hydraulic is good exercise..especially for extended periods of time. The Sky Gods usually dictate landing on a small pad in a confined area just for their continued amusement.