Beech G36 queries

I have just started flying the Beech G36 and there are 2 'unknowns' to me:-

 

1. The PFD shows an alert "busses tied" - what does this mean?

 

2. The MFD shows NaN (not a number?) for manifold pressure - again, what does this mean and how can I judge where to set the throttle?

 

Sorry if these have been asked before, but I could not find search terms to locate any answers.

B36 has 2 Alternators that may be tied by a contactor relay, Alt 1 is 100 amps and alt 2 is 20 amps. When Alternator 2 circuits are not being utilized (i.e., current demand less than 2.8 amps, RPM below 2000), Alt 1 supplies current to everything and busses are tied together through the contactor relay and the annunciator light comes on. Once RPM exceeds 2000 RPM, the relay drops out and you have two separate alternators and busses. Incidentally, if Alt 1 fails, you are in deep doo-doo. One of the things that alternator supplies current to is the landing gear motors. If your battery fails.... Bad Ju-Ju.

 

MP NAN, not sure why that's being reported. Good luck...

Thank you for the info. I still learn more when I fly, even after almost 4 decades of flight simming.

One of the things that alternator supplies current to is the landing gear motors. If your battery fails.... Bad Ju-Ju.

 

Of course in the real G36 there's a manual gear extension capability, as well, which just needs "armstrong" power.

Not in a G36, but had a situation where the 'armstrong' method had to be used. One of the gear indicators would not show 'down', requiring a tower flyby and a request to confirm the gear was, indeed, down. The ATC replied with "your gear APPEARS to be down." Now filled with confidence (LOL), a successful landing followed. I learned that in those cases, ATC will never positively tell you you're good to go...

I learned that in those cases, ATC will never positively tell you you're good to go...

 

For good reason. Just looking at the gear, there's no way to be absolutely certain that the gear is down AND LOCKED, or even just fully extended, though they CAN tell if it's an obvious partial extension or none. More than once gear has appeared down but one or more legs collapsed on landing.

 

I once had a similar deal with the nosewheel of a Cardinal not showing green (we could see the other two), and asking Unicom to check us (no tower there).