As shown by the image, the autopilot is set to NAV 2, on VOR radial 245; the plane is 99.3 NM from the station, and the CDI is centered. By this point, I would expect the autopilot to turn and intercept heading 245, with the green arrow pointer on top. Instead, it keeps tracking about 260, and it won't change direction from there. Can someone explain me if there is something wrong I am doing? Or is it this an erratic behavior?

 

Enrico

 

Well, after some more testing, I think I know what it is: crabbing. The picture above was taken during a flight at FL270, so there were winds aloft, likely cross winds, so the plane was flying into them to keep the needle centered. I am now trying to do the same thing at different altitudes, starting from 5000 ft, and so far so good, the needle is centered and the arrow points up on the gyro. Let me know, just in case my reasoning is wrong, but I believe the cross wind effect is what keeps the heading off the course, bye everyone. BTW: I think this plane is a joy to fly!

 

Enrico

FYI: it is not the crabbing, as I thought at first. I disabled any weather generator, and set the weather to user defined, with no wind, still the issue is there. At this point, I sent the Carenado support team a request via their support system, let's see what they say...will let you know, in case you encounter the same problem, regards,

 

Enrico

Hi everyone, I am still trying to find out what the issue is with the VOR nav mode, as described above. I would appreciate if someone would check this out and report back. As I said, this problem happens once I pass FL100, and the autopilot won't change heading to the green arrow pointer, once the CDI needle is centered. Carenado has not come back with an answer yet....let's hope someone here can give me an answer....regards,

 

Enrico

the plane is 99.3 NM from the station

 

I believe you have unrealistic expectations. Most VORs have limited useful range weil short of that distance. You may be tuning in a different VOR than the one you intended. Some VORs can be tuned at around 60 nm, but most at around 40 nm.

Just to clarify, confirm which NAV/VOR you are tuned to. The autopllot will fly a NAV tuned to NAV1 not NAV2.

Just to clarify, confirm which NAV/VOR you are tuned to. The autopllot will fly a NAV tuned to NAV1 not NAV2.

 

Hello Ron, I tried with NAV1 tuned in, and I had the problem, then I tried with NAV2 tuned in, and through the autopilot tuned to NAV2 the aircraft at first turned to intercept the radial selected, and then the same issue happened. Remember that with the C90B autopilot you can fly both NAV1 and NAV1, you just tell the autopilot which NAV to follow. I am not on the FSX computer, but if you look at the autopilot, you'll see there is a switch that lets you choose which NAV to track and follow.

 

Enrico

I believe you have unrealistic expectations. Most VORs have limited useful range weil short of that distance. You may be tuning in a different VOR than the one you intended. Some VORs can be tuned at around 60 nm, but most at around 40 nm.

 

Hello fppilot,

 

I do not believe my expectations are unrealistic, at all. VOR stations come in three shapes:

 

1) HVOR; these are used mainly for High Airways navigation (Jet Routes in the US), with a transmission power of about 200 Watts; their coverage between 18,000ft and 45,000 ft is about 130 nm,

 

2) LVOR

 

3) TVOR

 

One of my test was conducted at 25,000 ft, with a HVOR; the NAV radio equipment on board picked the signal up, as it is expected, and turned to the radial, until the CDI was centered, after that the autopilot should have turned to place the arrow pointer up on the directional gyro, but it did not. I tried the same experiment with a few other aircraft I have in my hangar, and all of them behaved as expected. So, as you see, something is not right with the C90B.

 

BTW: Carenado has not come back to me yet....

 

Enrico

Since I have this aircrft Ill give it a try today or tomorrow and let you know.

I fly with a separate cockpit layout, meanng I have a glass cockpit system on a separate monitor flying Project Magenta so I will be able to compare by showing both that and the C90 panel simulataniously. Should be easy to see if its the nav software or the flight model.

I have a short flight planned for this afternoon in the C90 as well so I will use VOR rather than GPS navigation and see what I find.

Well, I flew a short flight from Bloomington, Indiana, to Champaign, Illinois. I will preface my comments below by remarking that though fully instrument rated IRL on analog gauges for about 10 years, ending in the mid-80s, I have in recent years done most flight navigation in FSX by GPS. So I need to say that beyond a significant number of ILS approaches in FSX I have not done a lot of FSX VOR to VOR cross country, though that's the way I was trained to fly. i.e. I certainly know how to do so.

 

Because the length of my flight was only just over 100 miles I did not go above 8,000 ft. I tracked just fine into my interim VOR, TTH, which is about 35 mi from Bloomington. The needle did deviate from course a couple of times, but only by a degree or two and the HSI indicated course correction back to course. I was surprised as I passed the TTH VOR and the flag switched "to" ---> "from". My NAV light extinguished. I did not notice it at first, but when I began deviating from the course I began to investigate. That's when I noticed the NAV light was no longer on. Now. I use a Saitek Multi-Panel and use SPAD to drive it. I honestly do not know if the panel glitched on me or if it was FSX and/or the C90 model. I don't recall using the Multi-Panel for VOR navigation before today. I have only had it about 3 months.

 

After activating NAV again I tracked "from" TTH for a handful of miles, then toggled over to the CMI VOR at Champaign. At the time I toggled I saw the flag turn to "to" and the needle was centered. I was busy planning my approach after listening to ATIS as I did that switch from TTH to CMI. A couple of minutes later I noticed a deviation from the VOR course and it appeared to be wind driven. I quickly checked my Multi-Panel and found the NAV light extinguished again. This time when i reactivated NAV I did not get an immediate correction. I waited a few seconds and still no correction. I switched NAV off and back on, then cycled the GPS/VLOC function of the GPS (RXP GNS430 in this case), cycled the NAV switch on the AP again and finally it started to correct. Once back on course it stayed to course all the way to the CMI VOR. I then switched over to GPS for my LPV approach to 22 at KCMI.

 

It appeared the NAV function turned off first at the passage of the VOR at TTH, and then I assume turned off again when I toggled the NAV frequency from TTH (113.5) to CMI (110.0). It certainly went out a second time. That said, when NAV was active and tracking I saw only slight course deviations that were corrected by the AP in a timely fashion.

 

I'll take a much longer flight in the C90 on Sunday afternoon, from Bloomington, In. to Easton, Md. and will make sure I use VOR flight from likely 15,000 ft or higher. I will report back on my experience.

 

Here's a photo of the Multi Panel.

 

Enrico,

Had time and processed some screenshots. They appear to tell the story of what occurred during my flight. See if what happens in this sequence is consistent at all with your experience.

 

 

11 miles from first VOR at TTH. Tracking nicely. Note the indicators from left to right. AP VOR ALT and NAV.

 

 

I did not capture a screen while on the "from" course away from TTH, but I know I reactivated the NAV switch and flew the "from" course for a few miles. Here is the earliest screen capture after I toggled from TTH to the CMI VOR. It's close to being on track, but note that the NAV on the HSI is extinguished. Taken at 48 NM out from CMI.

 

 

 

Here about 5 NM later, 36.9 out from CMI, it's still tracking close to the line, but note again the NAV indicator is off.

 

 

Another 15 NM later the course deviation becomes obvious. At this point I am aware of the deviation, but have not noticed the NAV indicator is not lit.

 

 

At this point, another 5 nm or just under two minutes later after struggling to figure out the cause of the deviation, I have succeeded in activation the NAV function again as you can see the NAV indicator is once again lit. HOWEVER, you can see from the HSI there is no correction underway. Now 17 NM out from CMI. Note that while struggling to find the issue I have not started my descent.

 

 

Finally after cycling the NAV function of the AP and the CDI and OBS selections on the GPS I finally get course correction from the autopilot. Don't know which action was the successful one. Still have not started my descent. Now 12 NM from CMI.

 

 

About a minute later. Big correction brought the C90 back to the course, but a big counter correction has started to compensate for the initial correction, which was severe.

 

In my case the issue appeared to be caused by the NAV function extinguishing. Not sure why at this point.

Okay. Verified two aspects of this today. Again, I am using a Saitek Multi Panel to control the autopilot, but I doubt that makes any difference. Tomorrow I will make another flight and keep the multi panel unplugged, using only the pop-up C90 autopilot.

 

I flew today from Champaign, Illinois, to Bloomington, Indiana using only VLOC (VOR) navigation. I took a circuitous route to fit in a number of VORs. I flew CMI - DNV - BVT - VHP - SHB - OOM. In all cases when I arrived at the zone of ambiguity (when close enough the needle starts to swing) for each VOR the NAV function of the autopilot extinguished. Also, in all cases when between VORs at the time I toggled from the "From" station to the "To" station with the NAV frequency selector the NAV function also extinguished. In both situations. station passage, and transition from one station to another, this uncouples the NAV function, the needle makes the adjustment to the current position's vector from the new target VOR, and allows the pilot to make the CRS adjustment, then reactivate the NAV function.

 

I used FS9 up until about a year ago and since starting with a new system and FSX at that time I have done predominantly GPS flying. My use of the VLOC function has been limited to ILS approaches. So because of that I cannot say today that the AP characteristics identified above are unique to this C90 model, or general to FSX. I'll let someone else answer.

Confirmed the above in two flights today. Autopilot NAV function extinguishes as it reaches the tuned VOR, and also extinguishes when the NAV is toggled from one frequency to another. My flight was at 9,000 ft as it was relatively short. I will be completing a longer flight Monday or Tuesday and will be near or above FL200. I'll navigate VLOC again and see if I find anything different above 10,000 ft.

Well, I took some time tonight and climbed to 17,000 out of KBMG headed east. SHB - RID - DQN - APE. I found it just the same above 10,000 as I did below 10,000. Set the inbound course to SHB. When over SHB (still below 10,000) the NAV function extinguished. I had preset the heading bug to the outbound course to RID, so I activated the HDG function. I then adjusted the OBS needle to the outbound course. I then made an adjustment to the heading bug to intercept the outbound radial a bit quicker. Just before I intercepted the outbound radial I switched back to the NAV mode. I then dialed in the next station, DQN, on the VOR receivers bottom side. When about halfway to RID I toggled to that DQN freq, The NAV function extinguished. I adjusted the OBS to center the needle, then switched back to NAV. The C90's autopilot tracked it perfectly. I repeated on the next three legs and had the same results.