Flaps ?

It isn’t as simple as adding more runway, there are other factors that must be considered. All aircraft tires have speed limits for one. Also beyond having enough distance to takeoff aircraft must also have enough braking power to stop an aircraft within the runway length from the takeoff decision speed. An aircrafts braking system will have a hard time stopping the aircraft at such high speeds as well as handle the associated thermal energy created.

The aircraft would have a climb performance penalty meaning it wouldn’t be able to achieve the necessary altitude/speed requirements once off the ground.

I don’t think there is anyway an aircraft can “get away with it” if it hasn’t been flight tested.

Yes, very true but I was talking theoretically. The practical limitations may well put a different outlook on things.

Back to the original question as I can speak from a small piece personal experience. Surely all flaps are checked before flight albeit they may not be checked in the fully deployed position ? They tend to put them down to the take off position as they taxi to the runway so surely that counts as a check ? I was on a Dan air 1-11 many years ago that had a flap fault that was discovered while we taxi’d out, and back to the terminal we went to find another aircraft 😉

What a longwinded way to say Take off or land flapless and you’ll get away with it provided the runway is long enough.:)

It isn’t as simple as adding more runway, there are other factors that must be considered. All aircraft tires have speed limits for one. Also beyond having enough distance to takeoff aircraft must also have enough braking power to stop an aircraft within the runway length from the takeoff decision speed. An aircrafts braking system will have a hard time stopping the aircraft at such high speeds as well as handle the associated thermal energy created.

The aircraft would have a climb performance penalty meaning it wouldn’t be able to achieve the necessary altitude/speed requirements once off the ground.

I don’t think there is anyway an aircraft can “get away with it” if it hasn’t been flight tested.

Ah, you have me there sir. I can’t answer that one.

Yes, but you can tell me the sun shines every day, but why does it shine? I would have thought the already knowledgeable people on this forum would want something extra ? if I’m wrong I wont bother next time 🙂

What a longwinded way to say Take off or land flapless and you’ll get away with it provided the runway is long enough.:)

Taking off and landing without flaps can be achieved yes, but each comes with it’s own set of issues. For take off, without flaps there is a performance issue on the runway, Vr increases meaning you may need a longer runway, which means V1 will increase, then in the event of a rejected take off Vmbe then comes into effect and will probably be limiting, obstacle clearance on climb out will become a factor, and also the faster speeds needed to remain airborne can effect turn radius’ etc in complicated SID patterns.
On landing, the LDA is a factor now, especially if it’s wet or icing conditions prevail, structural limits will play a part especially if heavy, Vmbe again for stopping, tire and undercarriage integrity.
There are many more issues associated with t/o & landing without flaps.

The correct definition of what flaps do is it enables you to have the same amount of lift at a slower airspeed rather than “gives you more lift”, technically it equates to the same thing but the former is the correct one.

If you take the lift formula CL = ½R V² + S
Where CL = coefficient of lift, ½ = a constant, R (Rho) = Density, V² = Indicated airspeed & S = wing area you can see that to keep CL the sums have to add up, so if you take from one you need to add to another, so if we take away the flaps, which in this case is S you have to increase something else, you have no control over R, and ½ is a constant, so the only one you can change is V² being airspeed. But as you can see with this, because V is squared it will have the biggest change on the formula.
Next for landing the same formula applies (obviously), but you also have to consider your kinetic energy, and the formula for this is K = ½MV² where ½ = a constant, M = Mass & V² is indicated airspeed. So it figures that because V is a square it must have the biggest factor on Kinetic Energy, so if you are coming in fast your kinetic energy is rather large.

So in summary you can deduce from the 2 formulas that you can indeed take off and land without flaps so long as the lift formula is met, but it doesn’t come without secondary (or even primary) issues associated with it.

Taking off without flaps??
http://www.airdisaster.com/special/special-dl1141.shtml

Would have been fine if they had built up enough speed and rotated accordingly.
But they rotated at a speed that would be normal, had they had their flaps set.

In addition, had the Captain moved the throttles to their forward stops immediately after stickshaker activation and lowered the nose, the aircraft most likely would have recovered from the stall.

Basically, the aircraft was capable of flapless takeoff, they just didn;t build enough speed and reacted incorrectly to the situation.

The point is though that most aicraft would get into the air, with enough speed, without flaps.

And there has certainly been many occasion where an aircraft has landed sans flaps.

Taking off without flaps??
http://www.airdisaster.com/special/special-dl1141.shtml

My point entirely. Thank you.

Shame that this has digressed into semantics but…

flaps are not a primary flight control.

Flaps are not control surfaces.

They come under Chapter 27 Flight Controls (27-51-00). They are flight controls. They are also called Lift Augmentation or Secondary Flight Controls.

Does the engine position help determine if flaps are required or not? As in, for example, would it be easier for a BAe Avro/Do328 JET/An-72/74/124/225/ATR/DHC-8/Il-76 etc to take off without flaps due to their high wing configuration over ‘conventional’ aircraft?

I would think that wing design is the driving factor behind flap/slat requirements for different phases of flight.

I could be wrong but I’m certain they are.

I haven’t heard of nor found any performance data for Flap 0 takeoff in any manual. In fact the takeoff safe aural warning is only inhibited when flaps 9 or 18 are selected meaning those are the only 2 authorized positions for the flaps on takeoff.

Does the engine position help determine if flaps are required or not? As in, for example, would it be easier for a BAe Avro/Do328 JET/An-72/74/124/225/ATR/DHC-8/Il-76 etc to take off without flaps due to their high wing configuration over ‘conventional’ aircraft?

I’m pretty certain the EMB-135/140/145 is NOT certified for a no flap takeoff.

I could be wrong but I’m certain they are. As always, however, I’m always willing to be corrected by those who have more knowledge than I.

Paul

There certainly are a few exceptions, the Fokker 70/100 and Embraer 135/145 being among them. It’s a little scarey when you’re on one of these for the first time starting the takeoff roll and you realise the flaps are still hiding in the wings!

Paul

I’m pretty certain the EMB-135/140/145 is NOT certified for a no flap takeoff.

Theres alot of a/c that sometimes juse use slats for takeoff, including the A300. Like Paul says, there are exceptions on quite a few aircraft when the runway is big enough.

Very few airports (if any) have enough runway for an airliner to takeoff with no flaps not to mention achieving the necessary climb gradient so I would say that no airliner can takeoff without them.

There certainly are a few exceptions, the Fokker 70/100 and Embraer 135/145 being among them. It’s a little scarey when you’re on one of these for the first time starting the takeoff roll and you realise the flaps are still hiding in the wings!

Paul

Flaps are not control surfaces.
Essentialy, they are merely an aid to flight. A plane, with the correct speed can land and take off without them.

Very few airports (if any) have enough runway for an airliner to takeoff with no flaps not to mention achieving the necessary climb gradient so I would say that no airliner can takeoff without them. I’m sure there are a few rare exceptions to the rule. As long as an aircraft can be configured for takeoff a lack of flaps for landing is much less critical. (but much more than just an aid).

…perhaps we could also check the gear operation during taxi… 😉 :p

The first answer hit the nail on the head.