Originally Posted by
Agile
I like your logic, but I had understood that he got overenthusiastic in the dive, overspeed past VNE, got blade stall, and consequently jack stalled.
just my personal reminder note: its an error to think that dual hydraulic have twice the actuator thrust power, two piston on the same shaft (with pressure equaly regulated for the two pistons), does not double the thrust.
only higher hydraulic pressure can do that and actually the dual hydraulic version has a slightly inferior hydraulic pressure.
single hydraulic: 40 bars
dual hydraulic: 35 bars
That may well be but the jack stall would be symptomatic of exceeding the G-limit not the cause. You would still have control of the aircraft but may be in a position from which you have neither time nor space to recover.
As an aside the RFM of the Astar 350D stated that if you encountered it you had reached the G limit and how to recover from same.
Because of the dual hydraulics on the 355 this was indicated by the illumination of the limit light. This was also in the RFM. No jack stall would be present, Hence we only demonstrated it momentarily to point out that you had reached the G limit, the light was on, no Jack Stall was present but they should recover immediately by reducing bank angle, lowering collective ect. As jack stall had already been demonstrated in 350 training there was no reason to do anything more in the 355 than a steep turn to illuminate the light and recover from that.
I am a little mystified by the video, it is counterintuitive that the heavier, more powerful 355 would require only 35 Bar of Hyd. Pressure vs the 45 Bar required on lighter, less powerful 350D. That is not what I recall being taught on my original factory course on the 355 in the early 80s.
Don’t have the RFM to hand but wonder what the ECL for a single Hyd. failure on a 335 or 350 with dual hydraulics states.
. Never flew a 350 with dual hydraulics and have had the sore arm to prove it. I experienced 3 Hyd failures in the 350D.
Many, many moons since I flew either one. Freely sprinkle, therefore, all the grains of salt you may feel are required