Power opening system for engine cowl doors

In an aircraft having a jet engine, said engine having an annular cowl covering at least a portion of said engine, said cowl being longitudinally bifurcated to form first and second cowl portions, each of said cowl portions being hingedly attached to said engine for swinging movement of each of said cowl portions between a first position in which said cowl portions are joined together and a second position in which said cowl portions are spaced from said engine to expose said portion of said engine, an apparatus for moving said cowl portions between their respective first and second positions comprising:

• a first linear hydraulic actuator associated with said engine and said first cowl portion and operable to move said first cowl portion from its first position to its second position;
• a second linear hydraulic actuator associated with said engine and said second cowl portion and operable to move said second cowl portion from its first position to its second position;
• hydraulic fluid reservoir means mounted on said engine for supplying hydraulic fluid to said actuators;
• hydraulic pump means mounted on said engine, said pump means having a suction and an exhaust, said suction being in fluid communication with said reservoir means and said exhaust being in fluid communication with hydraulic control means;
• said hydraulic control means associated with said reservoir means and said actuators and selectively operable to direct fluid from said reservoir means to said actuators to operate said actuators, said hydraulic control means including first valve means having a valve body including an inlet port coupled to the exhaust of said pump means, a service port coupled to said first actuator and an exhaust port, said first valve means further including a spool movable within said valve body, said spool having first and second lands thereon, said spool being movable between a first position in which said first land blocks said inlet port and a second position in which said second land blocks said exhaust port;
• second valve means having a valve body including an inlet port coupled to the exhaust of said hydraulic pump means, a service port coupled to said second hydraulic actuator, and an exhaust port, said second valve means further including a spool slidably mounted within said valve body, said spool having a first and a second land formed thereon, said spool being movable between a first position in which said first land blocks said inlet port and a second position in which said second land blocks said exhaust port of said second valve means;
• third valve means including a valve body having an inlet port formed therein coupled to the exhaust port of said first and second valve means and an exhaust port coupled to said reservoir means, said third valve means further including a spool slidably mounted within said body, said spool having a land formed thereon, said valve spool movable between a first position in which said land blocks said exhaust port of said third valve means and a second position in which said land is spaced from said exhaust port of said third valve means.