To: All
Once and for all understand this: Since in my work it is imperative to try to eliminate any problem that effects reliability and safety I made a few assumptions. These were eventually proven wrong and I learned something in the process. Jack stall is an acceptable condition on the AS-350 and it does not cause a danger. I saw it as a problem because I felt that the hydraulic system was incapable of overcoming the forces and on any other helicopter I have been associated with, this problem was never addressed. I saw jack stall as a problem related to the reliability because in my misunderstanding of the conditions I felt the lower control system could react the flight loads. I saw it as a safety problem because in an emergency situation you would not want the jacks to stall. I also saw another potential problem and that was how the warning light was triggered and I was told that the warning light is on the Twin Star and not on the A Star. I thought the trigger was the system pressure and I was told that it is an external device that is mechanical with a micro switch or possibly a strain gage. The danger that I saw was that once the jack stall was taking place the pilot could not move his cyclic. To do so, would displace the servo (pilot) valve(s) opening the lower part of the cylinder to the return system and then the feedback forces could enter the control system and displace the cyclic stick quite hard and seriously hurt the pilot depending on which way the cyclic was displaced. But then again I am just a worrywart.