Leaderboard

Your default scenery seems damaged in odd ways. I suggest running the X-Plane Installer executable and updating/repairing the install. Then remove the CL650 directory from …/Output/caches, and trying again.

Right Pils, changed that into 4 cores. Luckily no effect on the FPS. Actually with my definitely less than stellar rig I get decent frames on the Challenger. Usually 40-ish, when going 'heads down' up to 55. So the aircraft is definitely flyable on such a rig.

I flew on Vatsim a couple of days ago with no complaints from ATC. I also tested it using the ATC client Euroscope. There should be no issues and any disparities are likely on the ATC side of things. FWIW X-Plane 12 will have realistic atmospheric simulation so ATC folks will have to fully fix things on their end eventually. Brgds

I am using Active sky. It had not caused problems so far

There are a few ways you can do this. First, if you are going to a single altitude constraint, say an along track waypoint, destination/-30 at 10,000, then you can use the DIRECT TO button on the CDU, line select the altitude into the scratch pad, and then re-enter it for the along track waypoint. That will re-sync the VNAV and execute a vertical “direct to”. If you’re in VNAV mode, e.g., VALT or VVS, the aircraft should recapture the VNAV path and change to VPATH mode. You can do this with any altitude constraint and create a vertical “direct to”. The second method is used of you’re descending on a STAR with multiple constraints. You can use the same method above to execute a vertical direct to the next altitude constraint. However, of that constraint is an “at or above”, then you have just changed that constraint into an “at” constraint. That will affect the downstream VNAV path angle after that constraint. You will comply with the altitude constraints on the STAR, but you may fly them at a much shallower VNAV path angle. Basically, the Collins VNAV uses the default VNAV path angle (3.0 but can be changed) and the lowest “AT” constraint, or the lowest “AT or BELOW” constraint, and then checks that 3.0 degree path back up through the remaining higher altitude constraints. If that path meets all coded/pilot entered altitude constraints, then the 3.0 path is used. If not, then the VNAV path is “smooth” between the constraints where is doesn’t work until it can again project a 3.0 degree path back to the cruise altitude for TOD. On a STAR with many altitude constraints, the best way to recapture the VNAV path from above when ATC interrupts the descent is to use either VVS or VFLC and descend at a rate equal to or faster than the target vertical speed shown on the vertical speed indicator (pink target bug) or as shown on the MFD Vertical Path information display. The only catch is that if the target constraint is a window altitude constraint, one that is both “at or above” and “at or below” altitudes, you need to make sure you capture VPATH before you reach that waypoint. Otherwise, you risk not meeting the “at or below” constraint. This is my preferred real world method. Rich

The same limitation is in the CL300/350 too, and to common to all Bombarider Collins FMS equipped aircraft. The reason for the limitation is that if for some reason the FMS looses the speed values entered into the PERF VNAV CLIMB page, the climb Mach speed reverts to M.50, which would be very bad if you are climbing in VFLC and the FMS ACTIVE SPEED on the PERF page in a ACTIVE <mach> speed, i.e., the speed bug and VFLC speed reference is pink. The airplane would pitch up and try to track M.50. At FL330, that would get exciting! You can climb in VFLC with and IAS value in the PERF ACTIVE <speed> active, i.e., a pink speed bug set to IAS, but when it transitions to Mach, you need to change to FLC, or you can move the speed bug which will change the target speed from the FMS ACTIVE speed to a FCP speed, i.e., CYAN/blue bug. Simply put, when in FLC or VFLC, you want the target speed bug showing cyan/blue. Rich

The model doesn’t have any odd behaviour with VFLC, and the reason for the limitation is unknown. IRL the VNAV is typically used only for descent anyway, as I mentioned above. You can use FLC in the climb, just not VFLC.

It's listed in Limitations under FMS and Vertical Navigation: VERTICAL NAVIGATION Vertical guidance deviation information is an aid to assist pilots to comply with altitude restrictions and plan descent profiles. When using vertical guidance the pilot must use the primary barometric altimeter to ensure compliance with altitude restrictions, particularly during instrument approach operations. Use of VNAV vertical guidance is prohibited when the barometric altitude is corrected to the landing field elevation (QFE). Use of VNAV vertical guidance is prohibited with a single ADC source when the 3rd FMS is reverted in. It is prohibited to select MCRZ from the FMS VNAV CRUISE page. Use of VFLC (FLC with VNAV) is prohibited during climb when the airspeed reference is displayed as Mach It is prohibited to select VNAV following a go-around during the missed approach procedure.