PPRuNe Forums - View Single Post - Takeoff flap setting
View Single Post
Old 24th Jan 2021, 17:45
  #19 (permalink)  
vilas
 
Join Date: Jun 2007
Location: Wanderlust
Posts: 3,407
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by pineteam
Hello Guys, I was reading a bit about the performance programs manual for A320 and the logic when OPT CONF is selected is as follow:

1> If takeoff is limited by performance, the calculation returns automatically the configuration that maxmizez the performance- limited MTOW.
2> If takeoff is not limited by performance and flexible takeoff is possible, the calculation returns the configuration that maximize the flexible temperature ( to reduce engine wear)
3> If takeoff is not limited by performance and 2 different flaps configuration provide the same maximum flexible temperature, the calculation returns the configuration that maximizes the V2/VS ratio.

For case number 1, what do they mean exactly by '' limited by performance''? Does it mean that let's say the maximum flex that can be used on on A320 is 60 but due to heavy weight a lower flex must be used and therefore by using optimum config it will chose the config with the highest flex?
And for case number 3 what do they mean '' maximizes the V2/VS ratio. Does it means to minimizes the gap between VR and V2?


Another confusing thing is in the FCOM-Performance- Take off recommendations:

'' If take off weight is not limited by performance, consider using the higher flap setting. Objective: To extend engine life and save maintenance.
I don't undestandhow using more flaps therefore more drags will extend engine life and save maintenance cost...

And last: I was playing on the EFB between Conf 1,2 and 3 for take off, for heavy weight the V speed are higher in conf 3 than conf 2 But not on lighter weight. Another mystery for me!

Any feedbacks from you guys will be much appreciated.

Thanks.
1. Performance limited means MTOW limited by available thrust, no flex possible. In that case select the Conf that gives higher TOW.
2. If Flex is possible select the one that gives higher flex.
3. If Flex is possible and same Flex in two different configurations then selects the one that gives higher V2/Vs, possibly for better second segment climb.
vilas is offline