Upon reflection my memory is you are correct....we did fly with one system or the other off as the control switch gave you a choice of each system off or both "On". It was with the Aux system off the controls got heavy. With the "Primary" system "Off" the controls just felt a bit sloppy.
I do not recall any Hydraulic failures during normal flight operations as the old girls were very reliable.
Originally Posted by
GCMOIR
Hi SAS, just picking up on your comment about flying the S58T with both hydraulics off. If you did this there must have been something wrong with the ship because the electrical switches are so wired that it is not possible to turn off both systems at once. Having observed the feedback through the cyclic when starting the rotor without the electrical ground hydraulic pump running gives an indication of the forces at play here and I seriously doubt you could control the ship in flight with both systems off. You're right about the "weight" of the controls when Aux hydraulics are off, they are very heavy.