Flap Position for Take Off

[Mike Bridge]

Ok,
I have always been told Flaps 20 for Take off

But i was just watching a Justplanes DVD - B777 from LIRF - LIMC used flaps 5 for take off and rotated quite quickly.

Is it benefical to use a lower flap setting ?

[John Khan]

I noticed this a while ago Mike when I first got the Polar DVD. They were using flaps 5 for take-off at some fairly heavy AUWs. Like from Tokyo to Chicago.

When I learnt to fly it was said to get the aircraft off the ground as early as safely possible and back on as slowly as safely possuble.

The same applies to their landings, they were landing with flaps 25 rather than full flaps. Dunno why.

John

[Mike Bridge]

I always land with Flaps 25
Rarely use Full.

Just interesting isnt it - To those of us FS Pilots only

[jcwaugh747]

Flap selection for takeoff is usually predicated on a combination of weight and runway length, with consideration for obstacle clearance during second segment climb.

The variation for landing flaps is similar, in that Flaps 30 will give you a lower touchdown speed (Shorter Landing Distance) and lower deck angle (Greater Forward Visibility) if going into a tight landing area, which for a 747 is still a pretty good sized strip.

The problem with higher flap settings (Flaps 30), is that they present a problem with gusty wind conditions or strong crosswinds. You will also see MANY abnormal procedures calling for a lesser flap setting, especially for approaches with one or more engine inoperative.

An easy thing to remember on the 747 is that Flaps 1 & 5 offer greater lift with very little drag. As you go beyond Flaps 5 the drag increases exponentially.

On landing, most pilots will find Flaps 25 easier to get a descent landing out of. Flaps 30 will bite you after the flare if you flare to0 high or are lower than Ref speed. But fun to practice.

So after this lengthy dissertation, it all boils to the fact that there are so many variables and it often comes down to pilots preference, unless of course the company puts in a protocol to follow.

[John Khan]

So whatever flap settings you have, make sure you get the right speed.

I don't think the FSims show the floating problem very well.

I've been in a (real) QF 743 with too high speed on landing and the damn thing floated for more than a quater of the length of the runway. It was a training flight at Avalon many years ago, with a brand new second officer at the controls and, of course, no pax.

It's hard to believe how much these huge aircraft will float at this time. It also made a great go-around practice session.

I was also in the cockpit of a, then TAA, 727 landing in Melbourne on an RPT flight, with a brand new first officer and a training Captain. The FO had about 7 or 8 knots too much on the IAS. We floated down 16 for a long time. Apparently the 727s were famous for this. They usually brought them in slightly below the calculated touch-down speed.

The training Captain sat there with his head in his hands, where are you now Vince??, and the FO lost about 3 kilos. sweating.

John

[Brogs]

Flap selection for takeoff is usually predicated on a combination of weight and runway length, with consideration for obstacle clearance during second segment climb.

The variation for landing flaps is similar, in that Flaps 30 will give you a lower touchdown speed (Shorter Landing Distance) and lower deck angle (Greater Forward Visibility) if going into a tight landing area, which for a 747 is still a pretty good sized strip.

The problem with higher flap settings (Flaps 30), is that they present a problem with gusty wind conditions or strong crosswinds. You will also see MANY abnormal procedures calling for a lesser flap setting, especially for approaches with one or more engine inoperative.

An easy thing to remember on the 747 is that Flaps 1 & 5 offer greater lift with very little drag. As you go beyond Flaps 5 the drag increases exponentially.

On landing, most pilots will find Flaps 25 easier to get a descent landing out of. Flaps 30 will bite you after the flare if you flare to0 high or are lower than Ref speed. But fun to practice.
So after this lengthy dissertation, it all boils to the fact that there are so many variables and it often comes down to pilots preference, unless of course the company puts in a protocol to follow.

So thats why I,ve been bouncing

[Marko Tesselaar]

Try landing a empty cargo plane with strong headwinds. Ever heard the story from the leaf falling from the tree. I have been in a few ferry 742 flights from MIA and ROW to AMS and they were mostly very ¨positive¨ landings, luckily the 747 is very strong
With the 747 they only use flaps 10 or 20 for takeoff as far as i know...

[PKlijnstra]

I just saw the WAR Polar Air Cargo DVD again yesterday evening and that crew used flaps 10 for take off, just like I do most of the times btw

[jcwaugh747]

I just saw the WAR Polar Air Cargo DVD again yesterday evening and that crew used flaps 10 for take off, just like I do most of the times btw

Flaps 10 would be the most common setting.

[Mike Bridge]

Hmmm, Will try my first Flaps 10 take off
Thanks for the information all

Great knowledge base here

[Marko Tesselaar]

And to make things a little more complicated
The official KLM freighter checklist i use from 2005 states in the before take-off part: Flaps ........... 20 set
So i guess it's also company related

[Mike Bridge]

Flaps 10 take off complete

Nice and Early rotations

[jacques]

Landing at Flaps 25 is my new favorite ! Very smoooooth . Thanks for a very useful discussion!

Jay

[Brogs]

No more Flaps 30 for me , 25 is the one !

[jcwaugh747]

I think it is best to look at it as having more than one tool to get the job done. Once you are comfortable using each tool, you look at each job and determine which ones would be the most appropriate for what you are trying to accomplish.

If you are going into a shorter runway that is WET, having Flaps 30 and the lower approach speed can be wonderful. If you are landing on 8R in HNL (An alternate landing spot for the Space Shuttle), it would most likely be overkill to use Flaps 30. The same holds true for Takeoff settings.

If you guys want to see some interesting variations, go through some of the abnormal and emergency procedures and try some of the landings which require unusual flap settings, such as a no flap landing.