When to use Flaps 3 ?

[Guest ciropv]

Hi. This is more a concept question (specially directed to real Airbus Pilots) about Flaps config at take-off and landings. I usually takeoff with Flaps 1+F and land with Flaps Full. But depending where you read it, you can find that Flaps 3 is even recommended.So:Take-Off: -When to use Config 1+F vs. Config 3?-Is Config 2 used anytime?Landings:-When to use Config 3 vs. Config Full?Is all this applicably the same to the A320/A330/A340?Thanks a lotSeeU

[Guest NEA_CEO]

>Landings:>-When to use Config 3 vs. Config Full?>For landings, Config 3 is prefered when the ground winds are gusting more than 5 to 10 knots. Vapp is then calculated as Vref + 20 knots (as opposed to the Vref plus 10 - 15 with Config Full)The rule is generally applicable to all airbus types.CheersMartin

[Guest Sjaako]

As far as the A319 goes:We only use Conf 3 when we cannot take off using 1+F or 2. So basically this is never. This will be airline specific though.As a general rule Conf 1+f is used on the longer runways where you only have to consider obstacles.Conf 2 is used on the shorter runways to make a shorter ground roll but have a slightly lower climb gradient on 1 engine.On the line i'd say most take offs are conf 1+f and about 20% conf 2.for the landing you use conf3 when windshear is reported or when you are single engine and you expect to level off during the approach (circle,etc).Conf3 app will give more performance in the go-around because you have less drag.sorry cannot comment on the 330/340cheers, sjaako

[Guest ciropv]

Thank you very muchVery nice and complete answer.Just one more thing. You say "Conf 2 [..] shorter ground roll but have a slightly lower climb gradient on 1 engine". -Shorter roll because you need lower v-speeds? (so less roll to acquire it?). So, does it make sense to use always Conf2 (or even 3) in very heavy situations -MTOW- (where vR and v2 are so high that you need the whole runaway -even on normal runaways- to acquire it?)-Higher Flap setting = Higher lift, so why the lower climb gradient?Beacuse of the difficult to reach "green dot" because of the drag?Thanks a lot.

[Guest Sjaako]

Ok, I'll give it a try.I just checked the manuals, and indeed when conf 1+f you get a slightly better climb gradient. On both and on single engine case. The only reason I can think of is DRAG. Personally I think using conf 1+f at high weights is a good idea. This is mainly because of the higher speeds you need anyway to rotate, and using conf 2 will only lower the speeds by approx. 5 knots. (A319)The drag produced by the higher flap setting only really comes into play at higher speeds. when drag starts building up since the velocity is squared in the drag formula. So it comes into play near the end of the take off roll.So it's a trade off really, short runway, but weight to spare, use conf 2. At higher weights conf 1 should do the tric. (A319)

[Guest ciropv]

Thanks a lot.SeeU