PART I - DESCRIPTIVE

           (b)  In manual
           
                (i)  Manual operation of the controls may be selected
                     deliberately by operating a switch in the cockpit
                     (see para. 21) provided that electrical power is
                     available, or will happen automatically if hydraulic
                     pressure drops below 200 lb./sq. in.
                (ii) When operating in manual, control surface move-
                     ments are achieved through a mechanical linkage.
                     The spring-loaded hydraulically-operated pawls
                     automatically disengage and release the anchored
                     jack piston rods, allowing them and the jack bodies
                     to move freely with the control surfaces.  The con-
                     trols are heavy in Manual except the ailerons.

           (c)  Hydraulic power reserve
           
                Accumulators are fitted in the power control circuits
                to provide a reserve of power if the main hydraulic supply
                fails.  This reserve may be sufficient for a maximum of
                3½ complete cycles of aileron and elevator operation

25