Vnav Profile - descending through 10000ft / 250kt

[suniram 6]

A question regarding the Vnav descent profile of the busses (RW and Aerosoft)  when descending through 10000 ft with 250kt speed restriction:

 

When approaching 10000 ft on a managed descent the bus will correctly pitch up in order to slow down to meet the 250 kts restriction. However it seems that this shallower portion of the descent is not taken into account in advance in the calculated descent profile because the magenta dot will continue dropping,  making it always impossible to stay on the vertical path without using speedbrakes at this point... Is this how the real bus does it?  From my experience as a A320/A319 realworld passenger I would say it is not...??

 

On the PMDG 744 this does not happen. Even when nearly levelling off in order to slow down the plane will remain on the calculated vertical path indicated by the magenta dot...So, is there any realworld difference between Boeing and Airbus in this behaviour?

 

many thanks in advance

 

regards

 

 

 

 

 

[The Dude 6537]

There is no difference in this regard between Boeing and Airbus. You are fully correct that the Airbus would also take the speed reduction into account. 

 

But, the profile prediction is only as good as the data it uses. If there is more or less wind around FL100 than used in the profile calculations you will get deviations between the calculated profile and the actual. 

 

Large deviations are ofcourse not the norm. 

[suniram 6]

Thanks for your reply !  

 

best regards and happy new year !

[Aerosoft Team [Inactive Account] 51558]

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