On an aircraft with switchable hydraulics I would recommend the following actions, some of them already covered by other contributors:
1. Move the switch!
If it's OFF you want it ON; if it's ON you need it OFF. Simple. If nothing happens (hydraulic assistance not restored) confirm which way it is now selected.
2. Check the pressure if a gauge is fitted. Check the CB.
3. Before resetting the CB ensure the switch is OFF. You do NOT want to restore hydraulic assistance by the CB with the controls not covered.
4. Switch the hydraulics back ON if appropriate. Expect the controls to jump and expect to overcontrol for a few seconds. Think about what stage of flight you are in before re-selecting the hydraulics ON.
5. A running landing should be planned for.
Final caution. Hydraulic fluid is flammable, especially when in aerosol form so think about the possible further consequences. (Minor consideration: It also melts tarmac so concrete is a better surface to avoid later embarrassment)!
Last edited by ShyTorque; 15th Jun 2002 at 18:33.