EFB - Top Of Descend

[Redskins8813]

Hey.

I bought Aivlasoft EFB a couple of years ago, and are really happy with how it works. But after a lot of googling, and I still didn't find any answer, I thought I finally should post a question here.

I use EFB with Aerosoft Airbus A318 - A321, and in the airbus, I got the option ticked for "pause at the top of the descent", so I can do other stuff while the plane is on autopilot. But usually I like to start the descent about 200 nm from the destination, but the top of the descent in EFB shows about 140 nm from the destination, so I wonder if there is some option in EFB to change the "top of the descent", to about 200 nm from the destination so I don't need to take a steep dive or a couple of "go arounds" until I can start my approach at the destination, when I fly in around FL330?

Thanks in advance.

Best regards
Erlend Falck

[aivlasoft]

Hi Erlend,

 

the top of descent calculation in EFB is based on the rule of thumb "(altitude current - altitude target) [ft] / 1000 * 3". This gives you roughly the distance you need to descent to the target altitude. The top of descent in the Airbus is calculated based on performance tables. Both calculations are "right", but they will never match. The top of descent calculation in EFB is meant for General Aviation aircraft which have no FMC or similar technical equipment. In other words, it is recommended to switch off the top of descent calculation in EFB when you fly an FMC equipped aircraft.