1/. What does MP indicate? MP gauge is simply a pressure altitude meter. That is why when we are on the ground it indicates atmospheric pressure(QNH).
2/. What else changes when you change prop RPM? The experimental mean pitch will change. For basic forces on a prop. Lift, drag, weight, thrust, total reaction. A fixed pitched prop only has one best efficiency and therefore MP will always increase with an increase in altitude.
3/. What is the ONLY control in the cockpit that is capable of regulating engine power between 0% and 100%? Magnetos. With only one mag working, fuel burn rate will be less and power will be below 100%. With both mags off power will be relatively lower depending on altitude and airspeed. Some operators recommend only using 2 mags for takeoff and switching one off when in the cruise.
Ok smart guy, i have a few Q's for you.
1. If we have a hung start, what is the easiest way to remedy it?
2. When operating the PT6, what is the most fuel efficient stage of flight?