crj900 vertical navigation problem

  • There is no introduction about crj vertical navigation in the official website,but I found that when I came to the TD point during the flight and used FMS as thenavigation source,when I lowered the altitude to the altitude of the landing airport,after pressing the APPR button,the screen VAPTH will appear, vnav should have been intercepted at this time,and then the aircraft will automatically control the pitch angle!But I don't understand why the vnav cannot be intercepted sometimes when the aircraft is on the correct vertical profile?

  • There is no introduction about crj vertical navigation in the official website,but I found that when I came to the TD point during the flight and used FMS as thenavigation source,when I lowered the altitude to the altitude of the landing airport,after pressing the APPR button,the screen VAPTH will appear, vnav should have been intercepted at this time,and then the aircraft will automatically control the pitch angle!But I don't understand why the vnav cannot be intercepted sometimes when the aircraft is on the correct vertical profile?

    When the aircraft is in a vertical profile, sometimes the vnav can intercept at around 40nm, sometimes at 25nm, or 15nm, or sometimes there is no response at all. I don't understand what is wrong! :(

  • The CRJ does not have a normal VNAV mode for descending. The VNAV is for guidance only.

    However, we allow the VNAV mode to be captured for an RNAV approach. This means if you press the APPR button with an route without an ILS approach then the VNAV mode will be armed. This approach mode only captures when you intercept the virtual glide path for the approach. So even if the route appears to be at the same altitude you may not be beyond the final approach fix where you can capture the final approach segment with VNAV.