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JRBarrett

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Everything posted by JRBarrett

  1. The excessive turning after a course change in the current version is by no means a “given”. Most of the time it works well. But, there are times it does not capture decisively. The worst case scenario seems to be when there is a substantial course change at high altitude and airspeed, with a strong crosswind coming from the outside of the turn, as this tends to push the aircraft away from the new track as it is trying to capture. Any changes to be made in this area will be thoroughly tested before being released.
  2. The developers are definitely aware of this problem, and a new system for intercepting the outbound leg when the course changes at a waypoint is being implemented, based on how the real CRJ autopilot operates. The initial part of a course change generally works exactly as it would in the real CRJ. The problem (at present) is with the last part of the course change. The actual autopilot is limited to two fixed bank angles when turning under autopilot control - either 25 or 12.5 degrees. (The sim uses 30 and 15 degrees). Above 31,600 feet, the only available bank angle is 12.5 degrees. For this reason, the real CRJ will use a longer DTA (turn anticipation distance) than other types of airliners with a more sophisticated autopilot that can dynamically vary the bank angle in a turn. When the autopilot is in half bank mode, the real CRJ will use a DTA of up to 11 miles prior to the waypoint if the course change is significant. The calculation of turn anticipation is based on the airspeed, the available bank angle, and the amount of heading change required. With a bank angle of 12.5 degrees at high altitude, even a DTA of 11 miles may not be enough with a significant tailwind, and the real aircraft can overshoot the new course line in this scenario. The main issue with the sim version at present is not overshoot but undershoot - i.e. the aircraft completes the turn before arriving at the new course, and then makes a series of “cut and try” banks to work its way onto the new course. The actual autopilot switches from constant bank mode to FMS CDI tracking during the final part of an LNAV turn. If the aircraft has not yet arrived at the new course, the aircraft will roll level, and monitor the FMS CDI deflection and centering rate to control the point where it will make the final bank to roll out on course. This is similar to how the autopilot intercepts a localizer. This change being incorporated into the sim CRJ, should result in a significant improvement in intercepting a new course in LNAV mode, without the constant banking seen now. Even the real CRJ may have to make one or two corrective banks once established on a new course to acquire the correct wind correction angle, but that is different than the long series of turns that currently can happen.
  3. There is also an STC which can give a CRJ the ability to fly an LPV approach with a GPS-derived vertical glide path. I do not think this is common in the airlines, as the modification is rather expensive, requiring new GPS receivers and hardware and software modifications to the FMS. It is only applicable to the WAAS system used in the USA - not the SBAS system used in Europe. The three corporate CRJ-200s I work on have the LPV mod.
  4. We are aware of this bug and what is causing it, but it will require another CRJ update to fix it. In SU5, MSFS is now using a more accurate way to calculate pressure altitude, and that will require a change at our end in how the CRJ processes Mach and IAS. The problem will not occur if you fly with the clear sky weather preset, but will be seen (to a greater or lesser degree) when Live Weather is active. I cannot give an ETA for the next CRJ update.
  5. As CRJay explained, as long as the bleed air selector is in “auto”, the isolation valve will operate automatically. The bleed air system on the CRJ 700/900/1000 is an improvement over the older CRJ-200, where the pilots have to manage bleed air manually. On that aircraft, if the isolation valve is closed, you would not be able to run the right air conditioning pack on the ground, nor start the right engine. The other thing that the automatic bleed air system does is to manage the main engine bleed valves. These must remain closed until the engines are running. If they are open (prior to engine start) the engine starter will not engage. As long as you keep the main bleed air switch in the auto position, all valves will open and close in the proper sequence.
  6. The CRJ can definitely fly a standard RNAV approach. However the real CRJ is not capable of flying an RNP RNAV approach, and such approaches do not even appear in the FMS database of the real aircraft. Flying these types of approaches requires FMS and autopilot functions that neither the real (nor simulated) CRJ has. RNP approaches do appear in the FMS of the sim version of the CRJ. At this time, there is no way to filter them out of the approach database as is done in the real aircraft. The aircraft might follow a very simple RNP approach, but if there are multiple RF legs in the procedure, it will almost certainly fail to track correctly. If you see the letters “RNP” in the approach procedure name in the FMS or on the approach chart, “proceed with caution” and at your own risk.
  7. I have very rarely seen this happen, but never for an obvious reason. What was the elevation of your departure airport?
  8. We are testing a potential solution to this issue.
  9. JRBarrett

    DME-H

    It is now.
  10. This is definitely fixed in the update. It is a long-standing bug, which actually had a very simple cause. Both the pack lights and “pack off” CAS message will now correctly illuminate any time the packs are off, regardless of engine state (running vs. not running)
  11. JRBarrett

    Minus 125

    At that temperature, the supply duct would begin creating solid carbon dioxide (dry ice)! Definitely a bug.
  12. I have not tested holds recently, so not sure of the status there…
  13. A couple of other fixes that can be added to this list: GS capture (which was broken by SU5) is fixed. VOR course sync for a tuned VOR now works when pressing the center of the left or right CRS button on the autopilot control panel. Confirmed that the autopilot will capture and fly a selected VOR radial in NAV mode. (Green needles)
  14. Using cowl anti ice during taxi would be standard practice any time the outside air temperature is below 10C and visible moisture exists (rain snow or fog). I’m not sure about the use of wing anti ice on the ground in the 700/900 series. I work (in maintenance) on CRJ200s, and the maintenance manual cautions that when testing the wing anti ice on the ground, to leave it enabled only long enough to do the required tests and then turn it off, otherwise the leading edges could overheat and become damaged. The 700/900 may be different. This would be a question for one of the r/w pilots on the test team. That said, our 200s are equipped with an optional “low temperature wing anti-ice system” that can be used for an unlimited amount of time on the ground. This system supplies bleed air at reduced pressure and flow rate (with temperature regulation) providing sufficient heating to prevent freezing precipitation from accumulating on the leading edges but not enough to potentially damage the leading edges from overheating. The LTWAIS may be unique to the 200. Because that model has no slats, it is far more likely to experience degraded lift on takeoff if there is any leading edge contamination.
  15. Also, the VOR course sync now works correctly- when you press the center of the CRS knob with a VOR tuned, the CDI will auto-rotate to center the needle on the “TO” course to the VOR.
  16. Our test team noted this same problem, which was exacerbated in SU5. A solution has been found, and the speeds should be working properly again in the update.
  17. This is now working in the latest development version.
  18. This is an RNP/AR RNAV approach, which the real CRJ is technically incapable of flying. The KDCA RNAV 19 approach does not even appear in the FMS of the real aircraft as a selectable approach option. The FMS in the sim version cannot correctly decode the multiple RF leg segments that appear in the lateral path of the approach definition in the nav database, which is why all the strange line segments appear. At this time, there is no reliable way to filter out RNP/AR approach procedures from the sim CRJ nav database as is done in the real aircraft.
  19. The flaps must be set to either 8 or 20 degrees or TOGA will not activate when pressing the button. This is also the case in the real aircraft.
  20. “Undercutting” turns is not itself a bug - especially at high altitude. The real CRJ autopilot is limited to a single fixed bank angle of 12.5 degrees above 31600 feet, and with a sharp course change coupled with high airspeed, the real autopilot can begin a course change as much as 11 miles before reaching a waypoint. What is not correct however, is the “hunting” behavior that sometimes occurs when the aircraft is trying to get established on the new outbound leg. I have sent Hans some info from the actual CRJ autopilot system manual on how the real aircraft handles the intercept of the new leg to see if there is any way to emulate it in the sim.
  21. It is definitely on the “to do” list. The indication of required descent rate is shown on the caret on the VS gauge once advisory VNAV activates, so I assume whatever is driving that indication can also be shown in text form - but since I am not a developer, I can’t say how easy or difficult it may be to add it to the MFD VNAV display.
  22. There does indeed seem to be an intermittent bug where the FD horizontal bar sometimes freezes, which apparently can be resolved by re-selecting APP a second time. (I posted that to our bug tracker). But, in general, the FD bar does not directly indicate glideslope deviation, but rather, the pitch angle you need for your current airspeed and flap configuration. It’s also important to always check the FMA (flight mode annunciation) in the upper left corner of the PFD to see what is driving the horizontal and vertical bars of the FD. The default on the ground (when no specific mode is selected) is ROLL/PTCH.
  23. Rotate the “format” knob to put the MFD into PLAN mode. (It is the outer ring of the knob you use to zoom). Then, press the MFD ADV key on the FMS. This will bring up a menu with two prompts that allow you to step through each waypoint of your flightplan from beginning to end, (or back). The zoom control is also active in PLAN mode.
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