Flaps Up?

[siucavflight]

Maybe you guys could help me with this.
If you are practicing engine failures on take off and you have 10 degrees of flaps down when the engine fails and you bring up the gear should you also bring up the flaps or leave them down because they are helping to provide you with some lift?

 

[U-I pilot]

is this in multiengine or single engine?

 

[HAZ-MAT]

You say it so much that you wake up saying it...
Mixtures props throttles, flaps up, gear up..........

 

[siucavflight]

Multi engine.

So you are saying that in no situation would you leave flaps down 10?

 

[HAZ-MAT]

In my mind that would be the PIC's choice all depending on the situation.. Now if you want to talk about worst case Scenario ...
Engine failure after takeoff to a down draft.... I'd keep current configuration (flaps t/o, and gear down) but i'd identify dead engine and feather it...
Some other please chime in.

 

[FL000]

It depends on the airplane. On the CRJ at ASA we are trained to leave flaps extended (either 8 or 20 degrees) until we reach our acceleration altitude of 1000' AGL (or sometimes higher depending on terrain), and then accelerate past V2 + 15/20.

 

[HAZ-MAT]

FL000, good point about Jets.. I'm speaking from light piston experience, and i am sure with commercial aircraft, and heavys for that matter you would want to keep a configuration until V2 or a specific altitude.. Thanks for the insight.

 

[bigsky]

I agree about saying it so much you hear it in your sleep.. Normally I would reccommend retracting flaps although there are some light twins that climb as well if not better with 10 degrees flaps. Your climb performance in most is so marginal so if you are able to do better with a notch of flaps it is worth considering

 

[tarp]

The flaps question is answered by your "drag demo" - remember that?? In any given piston multi-engine airplane you are introduced to - you should be doing a drag demo to see the relative "hit" at the lowest possible safe altitude. 10 degrees of flaps in a Seminole is negligible with the engine feathered and is about a 50-100fpm hit with a non-feathered (read spinning prop drag). In the Seneca, 10 degrees of flaps was a hit - in fact anything that made that pig have more drag was a hit on performance. Apache with 150's - pig, Aztec with 260's - indestructable, E-55 Baron - drag hurts -- at least in the models I've flown.

Note that in the Seminole, the flaps plus non-feathered prop create an additive drag factor - so you lose one on takeoff - is the prop feathered yet? No, I guess you better get those flaps up. In other planes, a small amount of flaps may not hurt performance but you won't know until you do a drag demo.

And yes I wake up in the morning yelling "Mixtures, props, throttles, gear up, flaps up, identify....". Too many multi students, too many chances to cheat death.

 

[avbug]

It all depends on the airplane and the circumstances. In most light airplanes, 10 degrees of flap will help, not hurt. What are you trying to do with the airplane? So often, students are told to plan on achieving "best glide" speed in order to maximize distance. However, in many cases, this isn't what's needed.

Light airplane pilots are constantly told to be looking for an emergency landing site. It's a valueable attribute to hold. Accordingly, one should be close by. It may not be a runway, but a field is as good as a road, which is as good as a taxiway, etc. This in mind, very often the landing site is right beneath you. Gliding the farthest distance isn't really what's needed in such a case.

A more useful speed, but one seldom addressed or taught, is minimum sink speed. This is typically less than best glide speed, and is a speed at which the minimum descent rate will be achieved. The airplane won't glide as far, but it will take longer to get down. The descent provile will be steeper, though it will take longer. As a very basic rule of thumb, best glide is typically close or approximate to best rate of climb. Minimum sink is typically close, or approximate to Vx, or best angle airsped.

In many airplanes, a low flap setting can enhance controllability, and decrease stall speed. Not all, but many. Retracting flaps may increase stall speed. A pilot is typically directed not to remove all flaps, but to retract them to a spedific minimum setting before moving on to gear and other checklist specific items.

Typically with flaps set for takeoff, they should be left alone during an engine-failure. If flaps for some reason have been placed to a greater position than takeoff, they should typically be retracted to the takeoff position.

The type of flap makes a difference. Split flaps do very little good no matter what the setting when contrasted with the need for drag reduction. Retract them. With other flap systems, it may be benificial to leave partial flap down. You may be in a situation wherein failure of other systems or loss with powerplant loss may mean that you can't get gear and flaps later. In such a case, view your situation as a gift, keep what flaps you have applied.

Did you really cheat death? He must be upset.