I’m trying to complete IFR flights with the Cessna 208B Caravan but it’s a hit and miss, more often a miss unfortunately. I may be doing something wrong but the autopilot just randomly loses the GPS navigation and switches to some random VOR, losing the ILS frequency in the process as well.
What I do before the flight:
I set the destination localizer frequency to NAV1. (In the example below, the localizer was 110.1.)
I switch the navigation source to GPS with the CDI button underneath the PFD.
This way, with everything set, the autopilot does follow the flight plan properly. When everything works out, the plane automatically switches to LOC1 at the final waypoint, catches the localizer and the glideslope (Approach mode on, of course) and I can land properly.
However, more often than not this plan is thrown out the window, because this happens:
The navigation source automatically switches to VOR1, without any input.
The NAV mode on the autopilot switches off.
The NAV1 frequencies get swapped, again, without any input.
Video (external Xbox link):
After this, there is no way to get back the ILS properly, or at least I don’t know how to do it. I swap the NAV1 back, I can switch back to GPS and turn on NAV mode again, but the plane will never find LOC1 again. All it does, if I press the CDI button, is switching between VOR1, LOC2 and GPS, but no LOC1. Not that I can’t land without ILS but this is super annoying.
Any ideas about how to prevent this? Do I set something up improperly? Is there a way to get the ILS frequency/LOC1 back mid-flight?
In the meantime I realized something important. The frequency on the left is actually the standby, and the one on the right is active. Looking at the screenshot I made, the 110.50 frequency was active during my flight, and it picked up the IIUM VOR for some reason. That could’ve caused the sudden change in source (I might have flown close enough to said VOR). Since then I could repeat the flight without problems, I put the ILS frequency to the active bracket prior to take-off and the plane didn’t divert from the flight plan.
However, this doesn’t explain why the autopilot switched sources by itself. All videos I watched about the ILS, the pilots don’t even touch this interface until it’s time to intercept the localizer. So what if someone does the same and doesn’t adjust the frequency, or, like me, just keeps the ILS in standby? Why does the autopilot think it should change course in the middle of the flight? This is something I still need to figure out.
I assume you were flying in Hawaii? IIUM is not a VOR. It is the localizer for the ILS 04R approach at Honolulu (PHNL). ILS identifiers always start with the letter “I” and have four letters. VOR identifiers have 3 letters. (Generally - some have fewer than 3 in some parts of the world).
Correct, I was flying in Hawaii. I’m not familiar with what’s what - when the aircraft switched to IIUM the CDI showed “VOR1” that’s why I called it a VOR. As it’s a localizer that explains why the autopilot switched to it. It was the active frequency and I was close to it. I was actually flying out of Honolulu. However, this is something to keep in mind in the future because that frequency was there by default. It definitely tricked me and I still don’t fullly understand the situation. Why it showed VOR1 when it was a LOC, even if not the one I intended to use… Anyway, for future flights I’ll make sure to set the frequency right and that it doesn’t show the name of something else.
The Working Title G1000 NXi from the marketplace may help resolve any remaining quirks you have. I imagine even the developers are using it instead of the stock G1000.
Just an FYI. I am on Xbox and installed the NXi before I completed all of the training missions. I had to uninstall it to complete the IFR training missions as it didn’t load the flight plan into the NXi. I have also read that it can have problems with the flight plans not loading for the Bush Trip activities with planes that have the G1000. You can still complete the flights but you won’t see the GPS course in the VFR Map window. I plan to test this at some point. Right now I want to complete all of the Bush Trips that feature the XCub. After that I think I will try the Bush Trips that feature the Savage Cub.
Thank you for the heads-up. I won’t download NXi just yet, because I’m in the middle of a bush trip and I don’t want to mess it up. That said, I’m not sure my original issue was a G1000 bug in itself. It’s probably a combination of some unfortunate circumstances as well as my lack of knowledge.
Firstly, I didn’t set the appropriate frequency as active prior to taking off.
Secondly, Honolulu is a special case where one of the localizers has the same frequency as which the G1000 has by default, and since I didn’t set it properly, right after take-off it connected with the unintended localizer, immediately switching sources.
Why it displayed VOR1 instead of LOC1 is something I’ll probably never know. However, since then I completed several flights and by setting the frequencies properly, I never ran into the same issue again. I have more problems with the ATC now who always sends me up and down constantly, even disregarding my Nav Log. But that’s a story for another day.
But that’s a story for another day.