USING Dial-A -Flap?

[Guest tcable]

From what I can guess so far, unless using the 'standard' flaps 15, how do we know when to use dial-a-flap?Will the FMC tell us so in the INIT flows?Obviously we're not running off of dispatch forms :) Closest I have is FSBuild.Tim

[3-2-1-Now 126]

Hi,Do what you feel is right (it's the best we've got without performance tables - PMDG are aware of this problem and are working on it, but they're having to contend with Boeing who will not permit release of the data).A lower flap setting means higher V-speeds, more runway use but a better climb rate, whilst a higher flap setting means reduced flap settings, less runway usage but a poorer climb rate.Don't confuse rate of climb with angle of climb however - when clearing high terrain or other obstacles, angle of climb is preferable to rate of climb - you gain the most altitude for a given distance traveled. Again, we're lacking tables for this. :(Best regards,Robin.

[Guest tcable]

I'm fully aware of best angle vs best rate- but how would you know that?For the sake of argument, I want to get off the ground the fastest (shortest ground roll), with no issues of obstacle avoidance.So for now it's just play around. and use the longest runway that you can when heavy. :)

[michal 44]

>For the sake of argument, I want to get off the ground the>fastest Then use some typical flaps - for example 22 and do not derate engines (use full available power). Runway length will only be super critical when you re talking about an engine failure during takeoff. With all 3 engines working fine - I think the problem of runway length is purely academical.Michael J.http://img142.imageshack.us/img142/9320/apollo17vf7.jpg

[byork 2,259]

This is what my consultant for FS2Crew MD-11 (who is a real-world MD-11 First officer) told me about dial-a-flap if you're interested:"Usage of the dial a flap may vary depending on the operator. For us: 25 is the standard flap setting for t.o. It is not the best setting but is a good compromise. If your t.o. weight is more than allowed by the runway/weather you can use optimum flap setting. This is between 11 and 25 and is the setting allowing the maximum take off weight for that runway. If you use optimum flap you cannot apply flex take off thrust and you must use full rated t.o.Since MD11 is the commercial aircraft with the highest wing load, it also has the highest t.o. speeds. We prefer to use 25

[Guest rellehenk]

Totally untrueAt my company, we always use optimum flaps/flex/packs off take off. It's standard! I would like to add: this is caculated with an ACARS performance tool. In the past, we used TL-tables and the standard was Flaps 20/flex/packs on. If we needed optimum flaps for performance, we did not have the tables for optimum flaps AND flex temperature, because you need a lot of tables in that case, so we used full thrust in combination with optimum flaps.

[SAS263 1]

Did you miss the part when Bryan said "Again, that's how his airline does it, others may have do things differently."?

[Guest Debosonic]

Pls explain what is flex and flex temperature...I am not familiar with that...

[Guest rellehenk]

Yes, but he says: "If you use optimum flap you cannot apply flex take off thrust and you must use full rated t.o."And that is not true. ;)

[byork 2,259]

>Yes, but he says: "If you use optimum flap you cannot apply>flex take off thrust and you must use full rated t.o.">>And that is not true. ;)>>Well, I've never flown an MD-11, so I can't comment.But perhaps David Bartoli (My MD-11 FO Consultant) will read this thread and he can step in debate this concept.He's got a zillion hours in the MD-11, so I'm sure he knows what he's talking about :-)His reference to "cannot apply" may very well be company specific and true in the context of his airline, but not others.Bryan

[Shmiffy 0]

>Yes, but he says: "If you use optimum flap you cannot apply>flex take off thrust and you must use full rated t.o.">>And that is not true. ;)>>So.... What you are saying is that his companies SOP's are wrong?Nobody is disputing that it cannot be done. All that is being said is that at his company. 'you cannot apply flex take off thrust and you must use full rated t.o.'Simple as....In the real world, the 744 can have it's engines started in pretty much any order you like. At BA, it's 4+3, 2+1. Just because thats the way BA do it, doesn't make it wrong....CheersPaul

[Shmiffy 0]

George:A Flex Temp is a derated 'false' temperature that airlines use to confuse the FMC into thinking that the outside air temperature is hotter than it actually is. The purpose of this is to save the engines from working unnecessarily hard on the take-off roll, by limiting their EPR or N1 to a lower level. This obviously means that the engines are not working quite so hard throughout their working lives, resulting in a saving in fuel, maintenance costs, and new engines. Programmes like Topcat, are very good at calculating this data (certainly for PMDG's 744) and will hopefully one day be able to do the same for the MD11.CheersPaul(sorry to the OP for the thread divert there ;) )

[Krister 51]

Adding to Paul's comment, here is a website with some interesting information for us flight simmers: http://askcaptainlim.com/content/view/166/90/

[Guest rellehenk]

No what I am saying is that a combination of FLEX T/O thrust and optimum flaps is possible. I am fully aware of the fact that company's have different procedures. All I wanted to make clear is that it is not a limitation of the aircraft.Absolutely no flame intended ;)CheersAnother MD11 pilot

[Shmiffy 0]

Hi there:My Bad ;)Misunderstood the gist of your response. I'm off to get my head out of my ####...CheersPaul