1. If I start a flight and my air tank is empty and move the flap lever to down, why will the flaps not drop? Are they being help up by air pressure, and if so, wouldn't that cause them to drop if there was no air pressure?
Answer: The flaps are held up with a spring system. That's why they come up if you raise the flap lever. The only thing the airsystem does is force the flaps down.
2. I drive buses part time which are equipped with air brakes. With the engine off in the Spit, would "pumping" the brakes cause air pressure to bleed off like it would in a bus or semi equipped with air brakes?
Answer: Yes it will, but will take a while to do so.
Hope this helps