I have the green light on in the auto pilot of the DC3,but it won't hold my heading.Also magnetic compass is not reading.Is that just for nav radios?Thanks,Ron

The DC-3 has a very old style AP (one of the first) and doesn't really have heading hold per se, but there are two heading related knobs on the panel. One is for the directiona gyro built into the unti and one is for the heading you want the aircraft to fly. If you adjust the DG thinking you're setting the heading then you won't get the results you are looking for.Just set the DG to what the compass is showing (which is what it should default to anyway), then adjust the heading knob to the heading you want. The compass is a completely separate instrument mounted on the glare shield.Also, although you didn't ask, many people are confused by the vertical component of this AP. It works on attitude hold so it will just hold the pitch attitude indicated on the included attitude indicator. It can be tricky to get the AP to hold a specific altitude.

Thanks for the info.I will work on it tonight.Ron