How do i get into the glide slope properly?

[hermansoepkip 0]

Hello everybody,

 

first of all, i'm new here but certainly not new to FSX. Played it a few hundred hours already But theres a few things on my mind what i've never really worried about, but now i'm trying to make my flights as realistic as possible, i'm kinda stuck at one point.. My problem is, when i'm descending towards my destination (i fly VFR flights and plan them myself because the default ATC in IFR flights always screws up my approach, so i always start descending at a myself calculated point) and i start descending too late, it causes me to have to make a go-around, and when i start descending too early i always keep flying at around 2000 feet above the altitude level of the airport for ages untill i catch the glide slope. Now this doesn't really seem realistic to me, and i wonder if theres a way to just immidiately get into that glide slope after descending from my cruise alt... Does anyone have a solution for me? (just assume that i fly the PMDG 737-800NGX, because this is the plane where it occurs the most when i'm flying it) And then there's another thing about this PMDG 737-800NGX. When i'm descending, i always descend at 1800 feet/min, but when i do that in the NGX, my speed will increase till i'm at the altitude to make my approach, which causes me to fly away from the airport to loose speed and after that fly towards the airport again (which causes the first problem most of the times)... So, thanks in advance to the one who has a solution for me!

Cheers

[MarkW 1,492]

You really should be flying an IFR flightplan and taking advantage of the VNAV capability of the NGX.  The -800 is slippery so you need to enter the forecast winds into the FMS so the VNAV will calculate the top of descent properly.  You can do this yourself with v/s (please note this mode does not give you altitude protection so you can descend all the way to the ground) just use 3 or 4 times your distance to destination times altitude and descend at 1800ft/min.  you will need to adjust as you get closer....perhaps increase rate of descent or level at 10,000ft to make the profile better match capturing the ILS at 3000ft and 10 miles out.  

[hermansoepkip 0]

Thanks for the reply MarkW, what exactly does VNAV do? I'm always afraid to use it because if it uses a rate of descent which is more then around 1700fpm, i'll end up flying at 300kts at 3000ft... And i believe it's a rule not to get above 250 kts under 10000ft?

[gtrbarbarian 1]

In the U.S. yes 250kts under 10000ft.... you can program into the FMC a speed/altitude restriction for each waypoint.... by entering 250B/FL100 to the right of the waypoint. That is, pass 10000 at or below ( B ) 250 knts.

 

http://forum.avsim.net/topic/345956-what-is-the-meaning-of-the-ab-etc-in-the-speed-fmc-etc-250bfl100/

[Mike777 163]

 

 

Thanks for the reply MarkW, what exactly does VNAV do? I'm always afraid to use it because if it uses a rate of descent which is more then around 1700fpm, i'll end up flying at 300kts at 3000ft... And i believe it's a rule not to get above 250 kts under 10000ft?

 

Hi, Hermansoepkip,

 

You often need to slow down during a descent by applying the airbrake, lowering flaps when at a low enough speed, and even lowering the gear early.  You should set speed constraints as Jonathan suggests, but this will not guarantee that the plane does not exceed these constraints.

 

The NGX comes with two tutorials.  The first one covers normal descent planning using VNAV, and discusses the need sometimes to add drag to slow down.  It will give you a great deal of insight into descending, even if you don't always use VNAV or fly other aircraft that don't have it.  The second tutorial involves a particularly steep (and very complicated) descent into a mountain valley at Innsbrook where gear is deployed early as well to increase drag. 

 

However if you just try to use the descent portions of the tutorials you will probably find them very confusing; you would benefit a great deal from doing all of at least the first tutorial. 

 

Mike

[hermansoepkip 0]

Thanks Mike and Jonathan. I am now using the Legs page in the FMS more than i did first, i'm also using approach charts which i found on fly-sea.com. And the airbrake saved all of my landings, thanks for the tip, i did not know i could use them while in flight.. And i'm also using the Glideslope indicator on the NAV display now. I start descending at the calculated top of descent point, and after that i kept adjusting my FPM to reach the glide slope even without flying around at a certain altitude before landing, many thanks guys! All of those things really helped me with my approaches

[Mike777 163]

 

 

I start descending at the calculated top of descent point, and after that i kept adjusting my FPM to reach the glide slope even without flying around at a certain altitude before landing, many thanks guys! All of those things really helped me with my approaches

 

Glad to be of help!  When you get some time, check out tutorial #1 for the NGX.  You will learn a great deal, and what you learn will be useful for just about any jet, not just the NGX.

 

Mike

[hermansoepkip 0]

I'll read it this weekend Mike, Thanks