louisgr

ATC giving the descend too late

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Hi,

KBOS to KORF. Cruise Alt FL280. No SID and no STAR. ILS Approach R23 with CCV IAF. ATC did not give me any descent so I started to descend on my own over KORF and I had to backtrack to CCV and catch the ILS. I'm using Xplane 11.3 RC1. Am I doing something wrong ? I got the "expect ILS R23 with CCV transition" but never got the descent.I am using 2.5.0.6x64_R5.

I will send the log to admin@pilot2atc.com

many thanks

cheers

Louis

 

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Dave is unavailable due to illness but I will try to help.

This may be a bug but the first thing you can do is update to the latest version.  There have been fixes for TOD for the last couple of releases.

I fly IFR and since you have TOD you are likely as well.  If VFR this information might apply.

The biggest factor is the planned descent rate.  I fly the FF A320 and I  use 1700fpm as my descent rate and this works almost 100% of time.  If it stops working I will change to 1600fpm to move TOD earlier than my aircraft.   IMPORTANT: this must be done prior to filing as once the plan is filed you cannot impact the TOD by changing FPM even though it looks like it might.

Sometimes Descend... will come in a few nm so just being a bit patient is all you need.  At other times I just request my new altitude and go down.  Update the descent rate for the next flight.

If you find your fpm is too late during a flight you can update the fpm value, file the plan and obtain clearance.  This can happen up to the Expect... message.  After this point it can get pretty weird.

Have a great flight

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Bu

16 hours ago, JeB1952 said:

There have been fixes for TOD for the last couple of releases.

but I find that it's still an issue after testing. Here's a good example that I get time after time and I have the GTN750 with the VNAV set to be at 3400 at NIMLE to track. I know the GTN750 is accurate.

Here's what I test with P2A - I'm on the T266 victor at 8000 since the restriction is 7000 coming into PAJN via the Sisters Island SSR

On the RNAV-V Rwy 08 the IAF NIMLE is 3400 and 3400 at OGEME. With P2A set for 800 with the GS/Desent Rate all set for 800fpm. I go past the TOD and half way between the TOD and SSR my GTN is telling me that I now have to descend at a rate of 1100fpm if I want to make 3400 feet by NIMLE and still didn't hear anything from ATC. There seems to be something wrong with the P2A TOD calculations for GA aircraft.

Ok so now my GTN is telling me that I have to descend at a 1100 fpm so I ask P2A for an enroute descent which it approves at the pilots discretion, so I descend at 1100 fpm and half way from SSR to NIMLE ATC is telling me that I'm off course even though I'm exactly on the assigned course by P2A and don't hear from ATC any more.

I see the TOD marker in P2A and ATC should tell me one I get to the TOD to start descending at the assigned DscntRate but it doesn't. It's as if there's an issue with the TOD being outside the approach.

I'm going to test it again putting the descent rate at 300 fpm and just let it go and see what happens.

 

 

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well some good/bad news, I redid the same flight CYZP-PAJN  via T266 victor and RNAV-V R08 but I put my descent rate at 300 fpm. Here's how it went down.

1) A few clicks before my TOD ATC said "Expect the RNAV  approach to runway Zero Eight with the SSR transition  at JUNEAU  INTERNATIONAL  Cleared direct to RADKY then direct SISTERS ISLAND"

so far so good.

2) The TOD waypoint on the flight plan changed to the next waypoint "RADKY" before reaching the TOD waypoint. This is where according to my Descent Rate ATC should have vnav me to 7000 feet but did not.

3) After passing the TOD Waypoint and before "RADKY"  ATC instructs to "Descend and Maintain Six Thousand feet" even though I'm still on the T266 which is Restricted to 7000, ok good but now my rate of descent to reach 3400 is about 450fpm, so I descended at 400fpm.

4) After "RADKY" ATC instructs to  "Descend and Maintain Five Thousand Three Hundred feet"

5) Before the SSR ATC instructs to "Descend and Maintain Three Thousand  Four Hundred feet" so at this point all is good

I therefore did make the 3400 feet by NIMLE IAF as per the chart but I had to descend at about 450 fpm.

So what I'm seeing from this is that the closer you are from the IAF the worst it is but to far is also not good. So for example if you put your rate of descent at 800 in the flight plan you might need to descend at 1300fpm. But if you put the descent rate tow low like 300fpm ATC will/might descend you lower than the restricted for the victor you are on which is not good.

I would like to think that P2A is a great EFB with ATC guidance.

I don't think that there's an ATC program out there (yet) where you hop in the plane and press 1 or say ATC request clearance/departure/follow From/To with SID/Star/Approach with full ILS/RNAV Altitude Restriction vectoring without a flight plan.

 

 

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This is too much for me to take in and I can't grasp.  I do not have the memory or the knowledge to understand your detailed description. 

You will have to wait for Dave to return for these answers.

This did start with TOD calculations but doesn't see like this now.  300fpm what are you flying a glider?

 

 

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Please email me the log files for these flights and when I have a little more of my strength back I'll have a look.

Log files are located in: 
C:\Users\<UserName>\AppData\Roaming\P2A_200\Logs 
where <UserName> is your PC user name. Portions of the path may be hidden by default, so be sure Windows Explorer has Show Hidden Items checked in the View tab.
A new one is created each time you start Pilot2ATC, so if you take the most recent one when you have the error, you should have the correct one.  
 

Thanks,

Dave

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