ui123 6 Posted August 8, 2017 Share Posted August 8, 2017 Hi there, First of all thank you very much to all the developers for this really nice product. I really enjoy flying the CRJ. So I've done some flights in the past couple of days and there's one thing that I still don't get. When do I have to descend? I mean I've watched streams and videos, read the tutorial but I still don't know when to descent because the TOD point on the ND is always too late which means I have to descend at a VS of about -3000fpm and more, which is kinda fast in my opinion. So is this a bug that the TOD is not displayed correctly or am I just incapable of flying the aircraft ? Thank you very much and have a nice evening. Alex Link to comment Share on other sites More sharing options...
FraPre 89 Posted August 8, 2017 Share Posted August 8, 2017 You can use a simple method. Calculate the difference between your current CRZ ALT/Level and the first Restriction, share this value 1000 and multiply this value with 3. In this NM distance you beginns with the Descend. At beginn you read the Ground Speed and share this value 2 and multiply this value with 10. This is the vertical speed, you needed. Example Current altitude/Level = 37000 next/first restriction = 11000 difference = 26000 26000 / 1000 = 26 26 * 3 = 78 NM Current ground speed 486 Kts 486 / 2 = 243 243 * 10 = 2430 ft/min vertical speed 78 NM before the waypoint with the restriction you start the descend with an vertical speed 2430 ft/min. Link to comment Share on other sites More sharing options...
Emi 5161 Posted August 8, 2017 Share Posted August 8, 2017 Hi Alex, to answer your question from the header: Whenever you pass the TOD, ATC asks you to descend or when you feel it makes sense to descend now. We could do it more complicated (I am sure someone will give the detailled answer), but 3000fpm does sound reasonable. Going down with a normal 3° your V/S will be about 5 times your groundspeed. That makes up for around 2500fpm. A little bit more or less is totally normal. Link to comment Share on other sites More sharing options...
Nexus82 21 Posted August 8, 2017 Share Posted August 8, 2017 28 minutes ago, FraPre said: You can use a simple method. Calculate the difference between your current CRZ ALT/Level and the first Restriction, share this value 1000 and multiply this value with 3. In this NM distance you beginns with the Descend. At beginn you read the Ground Speed and share this value 2 and multiply this value with 10. This is the vertical speed, you needed. Example Current altitude/Level = 37000 next/first restriction = 11000 difference = 26000 26000 / 1000 = 26 26 * 3 = 78 NM Current ground speed 486 Kts 486 / 2 = 243 243 * 10 = 2430 ft/min vertical speed 78 NM before the waypoint with the restriction you start the descend with an vertical speed 2430 ft/min. ...and if you want to further fool-proof this valuable method above, my instructor taught me: if Talwind > 75kts = multiply altitude to lose by FOUR instead of three . and for even more safety, add 10% to required V/S GS = 486 486/2=243 243*10 =2430 2430*1.10 ≈2700 (2673) Off course this is just a numbers game of academic interest and usually you can make up for errors by deploying speedbrake and faster airspeed during descents if ATC permits (maybe these actions is frowned upon in a CRJ ) But with some very basic tools you can come a long way... Link to comment Share on other sites More sharing options...
blahhh 41 Posted August 9, 2017 Share Posted August 9, 2017 15 hours ago, fsxswissflyer said: Hi there, First of all thank you very much to all the developers for this really nice product. I really enjoy flying the CRJ. So I've done some flights in the past couple of days and there's one thing that I still don't get. When do I have to descend? I mean I've watched streams and videos, read the tutorial but I still don't know when to descent because the TOD point on the ND is always too late which means I have to descend at a VS of about -3000fpm and more, which is kinda fast in my opinion. So is this a bug that the TOD is not displayed correctly or am I just incapable of flying the aircraft ? Thank you very much and have a nice evening. Alex also you can configure the the vnav angle of descente (and so the TOD) in the mcdu vnav perf pages. Link to comment Share on other sites More sharing options...
david.hilker 32 Posted August 9, 2017 Share Posted August 9, 2017 Can I actually see the deviation from the glidepath somewhere? Link to comment Share on other sites More sharing options...
blahhh 41 Posted August 9, 2017 Share Posted August 9, 2017 Just now, david.hilker said: Can I actually see the deviation from the glidepath somewhere? yes on the pfd Link to comment Share on other sites More sharing options...
tangjuice81 2 Posted August 9, 2017 Share Posted August 9, 2017 I follow the charts for the STARs usually. But I use vox atc so most of the time they are on the TOD by a few miles. Link to comment Share on other sites More sharing options...
ReconB4 30 Posted August 10, 2017 Share Posted August 10, 2017 TBH the aircraft should tell you what descent rate to use in the MFD when you have a lower alt input at a waypoint, as you approach it. but it hasn't worked for me. Link to comment Share on other sites More sharing options...
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