Top of Descent
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Top of Descent
Hello, when do I know when I have to initiate descent? So if the constraints are in the waypoints I can go into Managed Descent for the Descent Marker. It should work thanks to VNAV. However, if the constraints are not included, I have no way of adding the constraints manually. So I then have to calculate the ToD myself. The problem with that is that I can't use any fix info in the MCDU to see the distance. Could someone please explain to me how I can easily determine the ToD? So it's not the calculation but how I see on the plane when the right time is?
- RicardoLVFR
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Re: Top of Descent
We are going to release an avionics update on the A32x family in the coming months, after its been implemented and tested on the A330neo. The CDU side will also be overhauled. that's coming. Our apologies in the meantime
Ricardo Morillo
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Managing Director/Owner
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Re: Top of Descent
Ok, thank you very much for this information. But how can I determine the ToD until then if I calculate it myself? I would then have to calculate backwards in the flight plan to get the correct distance to the ToD or is there an easier way?RicardoLVFR wrote: ↑Sun Oct 22, 2023 2:55 pmWe are going to release an avionics update on the A32x family in the coming months, after its been implemented and tested on the A330neo. The CDU side will also be overhauled. that's coming. Our apologies in the meantime
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Re: Top of Descent
TOD depends largely on the constraints in the STAR, and other airport environment situations.AviationLife wrote: ↑Sun Oct 22, 2023 3:09 pmOk, thank you very much for this information. But how can I determine the ToD until then if I calculate it myself? I would then have to calculate backwards in the flight plan to get the correct distance to the ToD or is there an easier way?RicardoLVFR wrote: ↑Sun Oct 22, 2023 2:55 pmWe are going to release an avionics update on the A32x family in the coming months, after its been implemented and tested on the A330neo. The CDU side will also be overhauled. that's coming. Our apologies in the meantime
I just pulled it from google if you want a rule of the thumb: " The correct calculation is to MULTIPLY the difference in thousands of feet between cruise altitude and pattern altitude by 3. Thus, if you are at FL350 and your destination airport's pattern altitude for your aircraft is 2,000 feet, the calculation would be as follows: (35 - 2) X 3 = 99 miles from the airport to TOD"
Ricardo Morillo
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Re: Top of Descent
I understand that calculation. My problem is that I can't see the distance to my calculated ToD in the MCDU because I can't use Fix Info yet. I would have to add up the distances between the waypoints or roughly estimate it on the navigation display. I wanted to know if there was an easier way.RicardoLVFR wrote: ↑Sun Oct 22, 2023 3:22 pmTOD depends largely on the constraints in the STAR, and other airport environment situations.AviationLife wrote: ↑Sun Oct 22, 2023 3:09 pmOk, thank you very much for this information. But how can I determine the ToD until then if I calculate it myself? I would then have to calculate backwards in the flight plan to get the correct distance to the ToD or is there an easier way?RicardoLVFR wrote: ↑Sun Oct 22, 2023 2:55 pmWe are going to release an avionics update on the A32x family in the coming months, after its been implemented and tested on the A330neo. The CDU side will also be overhauled. that's coming. Our apologies in the meantime
I just pulled it from google if you want a rule of the thumb: " The correct calculation is to MULTIPLY the difference in thousands of feet between cruise altitude and pattern altitude by 3. Thus, if you are at FL350 and your destination airport's pattern altitude for your aircraft is 2,000 feet, the calculation would be as follows: (35 - 2) X 3 = 99 miles from the airport to TOD"
- RicardoLVFR
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Re: Top of Descent
There is supposed to be a TOD currently, you don't see it?
Ricardo Morillo
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Managing Director/Owner
Re: Top of Descent
Hi,AviationLife wrote: ↑Sun Oct 22, 2023 3:28 pmI understand that calculation. My problem is that I can't see the distance to my calculated ToD in the MCDU because I can't use Fix Info yet. I would have to add up the distances between the waypoints or roughly estimate it on the navigation display. I wanted to know if there was an easier way.RicardoLVFR wrote: ↑Sun Oct 22, 2023 3:22 pmTOD depends largely on the constraints in the STAR, and other airport environment situations.AviationLife wrote: ↑Sun Oct 22, 2023 3:09 pm
Ok, thank you very much for this information. But how can I determine the ToD until then if I calculate it myself? I would then have to calculate backwards in the flight plan to get the correct distance to the ToD or is there an easier way?
I just pulled it from google if you want a rule of the thumb: " The correct calculation is to MULTIPLY the difference in thousands of feet between cruise altitude and pattern altitude by 3. Thus, if you are at FL350 and your destination airport's pattern altitude for your aircraft is 2,000 feet, the calculation would be as follows: (35 - 2) X 3 = 99 miles from the airport to TOD"
firstly I would like to say that ToD should be shown even without constraints because 50 feet above runway threshold should be used instead. I will check this behavior in the a321.
About the "workaround" if you calculate the ToD yourself then you can use distance to DEST value on LEGs page, last line
Kind regards
Sink-rate
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Re: Top of Descent
I see that. But if I have a constraint beforehand that is not in the waypoint, the ToD marker won't fit because I have to sink first. With Fix Info I could just draw a circle with the corresponding radius, but that's not possible yet. And that's exactly what it's all about for me. So I have no choice but to add up the distances between the waypoints to figure out when I need to sink.RicardoLVFR wrote: ↑Sun Oct 22, 2023 3:30 pmThere is supposed to be a TOD currently, you don't see it?
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Re: Top of Descent
All right, then I'll do it that way in the future and hope that the Avionic update comes and works in the 330-900 so that you can also implement it in the a321.Sink-rate wrote: ↑Sun Oct 22, 2023 4:08 pmHi,AviationLife wrote: ↑Sun Oct 22, 2023 3:28 pmI understand that calculation. My problem is that I can't see the distance to my calculated ToD in the MCDU because I can't use Fix Info yet. I would have to add up the distances between the waypoints or roughly estimate it on the navigation display. I wanted to know if there was an easier way.RicardoLVFR wrote: ↑Sun Oct 22, 2023 3:22 pm
TOD depends largely on the constraints in the STAR, and other airport environment situations.
I just pulled it from google if you want a rule of the thumb: " The correct calculation is to MULTIPLY the difference in thousands of feet between cruise altitude and pattern altitude by 3. Thus, if you are at FL350 and your destination airport's pattern altitude for your aircraft is 2,000 feet, the calculation would be as follows: (35 - 2) X 3 = 99 miles from the airport to TOD"
firstly I would like to say that ToD should be shown even without constraints because 50 feet above runway threshold should be used instead. I will check this behavior in the a321.
About the "workaround" if you calculate the ToD yourself then you can use distance to DEST value on LEGs page, last line
Kind regards
Sink-rate
@Sink rate, by the way, I answered you in the topic about the A330-900 about the engine off and trim tank
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Re: Top of Descent
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