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I’ve had this happen as well. The issue was that VNAV and managed speed were engaged during the cruise and the cruise speed was selected as LRC. At some point the FMS went nuts and computed the LRC speed as Mach 0.4, which causes the power levers to idle and the speed to drop and the autopilot disconnects so the airplane… spirals slowly into the ground. My solution until a fix is implemented is to manually select speed (cyan indication vs. magenta) if I need to leave the flight deck, as well as always saving the airframe state before walking away. You can confirm this is the cause by looking at the FDR report for your flight in the XPlane outputs folder. Check out the selected speed column and see if you find a super low speed right before the spiral.

So, this is a geeky issue that you may not see unless you're flying VOR or ILS green needles. I was flying the ILS or LOC Rwy 18 approach to Pine Bluff, AR (KPBF) looking at the teardrop course reversal. I was testing fly it in response to question I was asked, and I needed to fly it using just the VOR and the ILS green needles. A technique we learned a long time ago was when the CDI was centered, fly a heading that keeps the track indicator on the head of the CDI needle. That way, your track is following the course set in the CDI and you should not drift since the track indicator donut would be showing zero drift angle. Per the Collins CL650 manual, the track pointer shows the ground track over the earth. So, if it is aligned with the course arrow when CDI is centered, there should be no drift and CDI should remain centered. This is of course if you are using HDG mode to track the CDI instead of NAV/VOR mode, which is sometime easier if you're flying these types of approaches. Not everything is LNAV and VNAV! While flying outbound on the teardrop course reversal (PBF R-022) for this approach, I was able to find a heading that kept the CDI centered. However, the track indicator donut was several degrees off to the right: You will have trust me that did fly a heading long enough to find one that kept the CDI centered for a period of time. With track pointer showing as it is above, my ground track should be tracking to the right and away from the PBF R-022, and the CDI needle should be moving to the left. It's not. The CDI is remaining centered. The MagVar for KPBF is 4 degrees East. Is it possible that in HS CL650 the Track Pointer is showing True Track instead of Magnetic Track? It looks like the track donut is at 026 degrees, just ever so slightly left of the heading bug of 027. Going by the saying "east is least", subtract 4 degrees from a true track of 026 and you get 022, which is the PBF radial I am tracking. That's the only thing that comes to mind as to what might be happening here. If needed, I can try some more experiments. However, at first glace it looks like the track donut is showing True Track instead of Magnetic Track. Thanks for your assistance! Rich Boll

Part of the problem is that the world is tipping on its side, and it's happening faster each year. Doesn't bode well for those southern vacation spots in a hundred years or so! ;-) The reality is that in the US we're not updating the VOR MagVars that often, part it is due to the ongoing decommissioning process in the US called the VOR Minimum Operational Network. Adjusting for MagVar requires changes to the actual VOR and the FAA is just behind the problem as they work through the VOR MON program. Here's an FAA Aeronautical Charting Meeting agenda item discussing the MagVar discrepancies that can happen between conventional procedures and the MagVar in the FMS: Hist_11-01-296 (faa.gov). Here's one on use of MagVar on DMEs: 14-02-284-ACF_DME_Facilities.pdf (faa.gov) This InFO explains the differences between conventional procedures and FMS tracks: InFO 12009, Magnetic Variation Differences Between Ground-Based Navigational Aid (NAVAID) (faa.gov) Much of the issues are involved outdated MagVar tables in the IRU, collected by the field and used in procedure development and documentation along with the procedure not being updated. There's been much talk in in various industry groups, including the Aeronautical Charting Meeting, which is going on as I type, about moving towards using the Airport Reference Point as the source MagVar for all instrument procedures tied to that airport. All of these issues go away if move to True. Magnetic track, course, and heading is presented solely for pilot convenience. The FMs and IRU computes everything in True, then converts it to Magnetic so it agrees with the magnetic compass. Going to True would mean no more runway repainting due to runway number changes resulting from MagVar changes. It would mean no more mis-match between procedure tracks as MagVar changes. Rich

I had a look at this and it doesn't appear to be a bug or badly implemented track indicator. What you are seeing is the accurate magnetic ground track donut. The problem appears to be that the database-provided magnetic variation for the Pine Bluff VOR/DME is incorrect. You are quite correct that the databases say it's 4°E. However, and here's a funny one: the Pine Bluff airport near to the VOR/DME is is declared as 2°E: Now, as to how the airplane knows its magnetic heading - the IRSes contain a magnetic variation database, which is valid from 2020 through to 2025. The IRS feeds the current date + position and this database computes the actual magnetic variation expected at that position and that's what you're seeing on your avionics. And here's the kicker: the magnetic variation database says the actual magnetic variation should be around 0.3°WEST: Similar results using the IGRF magnetic model: You can run the computations for select positions yourself here: https://www.ngdc.noaa.gov/geomag/calculators/magcalc.shtml Investigating enroute charts, there's a 3 degree declination change over the span of a mere 65 miles. This seem to suggest that the Pine Bluff VOR/DME is misaligned and needs to be realigned IRL: To summarize: doesn't look like a bug to me. Seems more like either the navaid is misaligned IRL, or the navigational database needs to be updated.

Challenger 650 - Hamilton Livery (G-LCDH) View File This is the first livery I make. I start by saying that as a basis I looked at that of MadProf whitch i thank This livery will not be updated, except in case of visual bugs that ruin its appearance. But I accept any advice for future ones. Features: Custom PBR metallic effect Custom Interiors Submitter CptHeike Submitted 04/05/2022 Category General Aviation Livery For https://www.x-aviation.com/catalog/product_info.php/take-command-hot-start-challenger-650-p-212 X-Plane Version(s) X-Plane 11  

The simulated 650 FMS is fully capable of offset, and can micro-SLOP.