Shut-off valve arrangement for a gas turbine engine fuel

A shut-off valve arrangement for a gas turbine engine fuel system, comprising a shut-off valve having an outlet passage through which fuel can flow to the engine, and a control member movable in response to an increase in a servo pressure signal to an open position to permit fuel flow through said outlet passage, a drain valve having a drain outlet, an inlet port communicating with said outlet passage and a control element responsive to an increase in said servo pressure signal to prevent flow from said outlet passage to said drain outlet, and a servo pressure signal control means for selectively increasing or decreasing said servo pressure signal, said servo pressure signal control means comprising a first pilot valve for applying said servo pressure signal to said shut-of valve control member and to said drain valve control element, and auxiliary valve means operable by said shut-off valve control member for applying said servo pressure signal to said control member and said control element when said shut-off valve is open, whereby operation of said pilot valve to open said shut-off and drain valves causes these valves to be maintained open by pressure applied through said auxiliary valve means.