Questin about ILS/GPS

[Guest]

Hi all,Recently i've started flying ILS. Normally when I'm doing a flight I will fly direct to, and so instead of using NAV hold, set into GPS mode, I will use HDG hold. However, on my last two flights I've done VOR to VOR, and so I have been using NAV hold. The whole flight things generally go well, until the ATC starts feeding me vectors. First off, look to the picture below for reference. I start the transfer from NAV hold to HDG hold, as follows:1) Set from GPS to Nav on the Nav1 Radio (otherwise HDG hold won't engage on AP)2) Set HDG hold bug on the HSI into the heading I wantOnce this is done, the change starts to take effect, but unfortunately there are some problems. If you'll notice the picture, my attitude indicator shows that i'm flying straight and level, but my FD wants me to be heading to the right. Also notice that im about 30 degrees to the left of the heading I bugged. Now, after this happens, things start to get stranger. I will be set up for the ILS, and I will turn Nav hold on and set the OBS to the correct heading and the aircraft will start to make its turns, but will usually just head straight, rather than align me with the runway.Yesterday, nearly the same thing happened, but rather than sending me straight, the NAV hold would send me into 75 degree banks and just run me around in circles. I had tested earlier today to see if I was doing anything wrong, did pretty much the same things I did here, but the ILS worked fine. I had gained confidence, until this flight when I ended up just flying in by hand.I know that I'm probabably doing something very simple wrong, but I figured what better place to ask than here, and to get the advice of people who would know what they're talking about. Thank you all in advance for any help.

[Guest Crash_Hawk]

Scott,First, I noticed that you integrated the 421's GPS into the Commander. Nice to know that it works. Anyway, I think the problem you are experiencing is due to the GPS not 'thinking' that it is out of GPS/Nav mode. I'd like to point out in the lower left hand corner of the GPS (421's) there is the legend GPS in green. Perhaps you need to disengage the GPS/NAV from there instead of from the Commander's Garmin GNS 530. Were I at home instead of at work I could run a test, sorry I can't provide any data. Regards, Crash

[Guest]

Thanks for the reply Crash. To be completely honest I hadn't thought of compatibility issues. Perhaps thats the problem, with the GPS unit thinking that it's still engaged. I'll try with my GL50 unit and see how that goes. Thanks for the help though. Scott

[Guest Crash_Hawk]

Scott,No problem. Just make sure that all the GPS's say NAV. I can't remember but the little GPS in the corner could actually be telling you that you are on the GPS page of the GL50. Like I said, I'm at work so I can only work off of memory, and I don't even trust it sometimes. Again sorry for the lack of data.Regards,Crash