Three position actuator arrangement

A three position actuator arrangement for use in an aircraft gas turbine engine comprising:

• a cylindrical housing;
• a first small diameter piston having a drive shaft slideably passing through said housing;
• a second large diameter piston;
• said first and second pistons abutable with lost motion spacing therebetween;
• said pistons and housing defining axially spaced chambers comprising a first chamber between one end of said housing and said first piston, a second central chamber between said first and second pistons, and a third chamber between said second piston and the other end of said housing;
• a first conduit in fluid communication with said first chamber;
• a second conduit in fluid communication with said second chamber;
• a third conduit in fluid communication with said third chamber;
• a high pressure fluid source;
• a low pressure fluid sink;
• selection means for selectively connecting each of said chambers with said source and sink;
• and
• an adjustable stop rod adjustably secured to said housing adjacent said third chamber, slideably and sealingly passing through said second large diameter piston, and having a radial extension within said second chamber abutable with said second larger piston.