Problem during descent

[bloudman]

Hi everybody!

I am happy to see a forum with pro of Ixeg. I bought it last week and my skills are far away from perfection.

Tonight I tried to do a short flight between Lille (LFQQ) and Nice (LFMN). 
Before the Top of descent I changed the MCP for 4000Fts to start descent. And the descent began just on the top of descent.
Everything was good I was on the correct descent path. At the next waypoint something strange happened. I had to desend to 12000Fts in 10nm or something like that and I got a late of 9000 on the descent path.

What did I do wrong ? 

Is it the flight plan (made with PFPX :/ ) or somthing else ?

Thanks by advance I would try to understand to not repeat the same mistake 

[poodster]

VNAV is pretty basic, I would not fully rely on it on decent. Kinda what most RL pilots do. FL change (flight level change) is really helpful for these situations. You had to descent to 12000ft in 10nm, what was your altitude at the previous waypoint? So from what altitude were you going from to get to 12000ft

[bloudman]

I didn't know I use to fly with A320 and it is not the same :/ 
 

My previous waypoint was at 32000 feet 

[Litjan]

Poodster is right, the VNAV part of our FMS is not very good at handling multiple restrictions. And it´s certainly not designed to work like the Airbus´ one (thank god!)

But to really be able to see what the problem was, we would need a lot more information.

What STAR/Transition where you trying to fly? Can you post some screenshots, detailing the problem?

For now treat the predictions of the FMS with a bit of doubt and be prepared to revert to a more basic autopilot mode to meet your descent restrictions.

The aviation industry see the ill-fated dependency of unskilled pilots on "fully managed" automation with growing concern. Pilots need to learn their airplanes from easy to complex...not start with LNAV/VNAV and hope that the autopilot gets them to their destination in one piece .

Don´t take the fun of flying away from yourself. Its not a movie to enjoy with your feet up and a box of popcorn .

Cheers, Jan

 

[bloudman]

Yes I know obviously 737-300 and new airbus are really different   

I love also boeing because flight are less borring ! 

 

Sorry because i did'nt take screens when the problem happened :/ 

I made the flight today and found a solution. When Vnav does not get off the plane right away I switch to level change. When I return on the descent path I put Vnav and it leaves again;)

Thank you for the indication of the levelchange it unlocked me!

I don't know if it is a bug or something like that but juste 2 minutes of level change solve the problem