I bought the 737 NG a while ago, got frustrated with it, left it for a while, and now attempted to fly it again. I read the manual, but I am still unsure how to navigate using the autopilot and FMC. I can input all of the correct information into the FMC and I can take off and then cruise and climb with the autopilot. When I get closer to the airport, I am expecting the plane to start it's descent but it never does 😳 . I can't make the plane descend and pick up the glideslope. Any help pleeeease ?!
Although the plane has VNAV (Vertical Navigation), it won't actually descend completely on it's own as the MCP 'Altitude' setting that you have entered in the AutoPilot will always over-ride the VNAV settings that you have in the FMC.
The VNAV is there to 'maintain' an altitude rather than to make changes, so once you are the cruise, the idea with this aircraft is that you can select LNAV (Lateral Navigation) and VNAV and the plane will maintain the correctly set Route, Altitude and Speed for you. The only way the VNAV would automatically make an Altitude adjustment for you is if you adjust the altitude shown on the AutoPilot MCD display at some point before the plane is due to descend..... this will "free" the VNAV system to descend automatically at the right time for you.
The problem is that the FS2004 ATC will instruct you to descend at different times to the VNAV settings, so you'd normally have to switch VNAV off and descend using normal means, once ATC give you the instruction.
I'm not sure why you're not managing to get the Glideslope, but I did also struggle with this at first and it was because I was too fast, on Final Approach. Your speed should not be more than 150kts on final approach or else this plane will not capture the Glideslope.
If you keep your speed right it should capture it and glide down beautifully....
Also, if you wanted to try out the full AutoLand in this plane, just make sure you set the ILS frequency in NAV2, as well as NAV1.... this will allow you to select AutoPilot B, in addition to A..... which sets up the full Autoland.
As has been said many times, it's a very complex aircraft - soooooo close to the real thing - we all struggle with it (for weeks) at first, but once mastered it's amazing and you'll never fly another default airliner !
If you hand fly the app. you should have no trouble capturing the slope. That's how I do it. For verticle nav. I use time from initial app fix vs descent rate. I let the A/P handle the descent. Typically that's any where from 12 1/2 to 16 minutes from IAF, depending on cruise altitude. I generally level off at 6000' agl 2 minutes short of IAF, then set up for ILS.