Extending 30-40 degress of flaps while turning on approach

[Flightjock30]

I am just wondering if it is safe to apply a high degree of flaps while executing a turn to final at low speeds? I never heard anything about it being dangerous until today when a fellow pilot I know said it could cause a spin due to the assymmetry of simultaneously banking and extending all that drag out on the wing at approach speed. Just curious.

 

[NookyBooky]

......depends on how "slow" you are.

 

[Singlecoil]

Sounds like what he was trying to say was that if you get an asymmetric flap condition while extending the flaps and rolling into a bank, you may not notice it in time to recover when you are low to the ground.

 

[Flightjock30]

Singlecoil,
Ahh thats what he meant yes! So that means to never apply flaps while banking just in case of an asymmetrical flap condition from occurring?

 

[falcon20driver]

If in a C-150 with two people I HIGHLY advise NOT going 40 flaps until over the numbers.

 

[satpak77]

I am just wondering if it is safe to apply a high degree of flaps while executing a turn to final at low speeds? I never heard anything about it being dangerous until today when a fellow pilot I know said it could cause a spin due to the assymmetry of simultaneously banking and extending all that drag out on the wing at approach speed. Just curious.

dude the only thing that causes a spin is a stall. No stall, no spin. Obviously we have stalls in training and no spin, thats because (not the MIT Aerodynamic explanation) the "ball is is the middle".

However, to spin you need to stall. And to stall you need to exceed the critical angle of attack. Stall is NOT dependent on power setting, "nose on horizon", IAS, etc. Your CFI can get deeper. In simple terms, STALL is a "wing concept" and independent of airspeed, engine/lack of engine, etc.

http://www.aopa.org/asf/publications/topics/stall_spin.html

"low speeds" needs to be looked at in the POH. I recall a "stall speed vrs. bank angle" chart in the Cessna POH's. Take a look at that. Take the worse case scenario you might typically be in and make a mental note to "dont be slower than XXX when I am in a steep bank".

remember this is 1-G ops. The plane stalls at XX when it weights YY. If it weighs 2-YY's then the stall speed is ZZZ. Hence accelerated stall practice.

however, to expand on your question, might as well start flying like the professionals, which requires "stabilized approach" to exist prior to landing. According to the FAA, one component of this is to be in (per the POH) "landing configuration). This means no "extend flaps on short base" or similar stuff. I understand you are in a C-150 or C-152, and we can do things in that all day long you would never do in a Falcon 2000, however, might as well get into the habit.

I recommend (per POH) "flaps set", "approach speed/V-ref on target", "belts secured", "landing clearance pending/obtained", "correct runway confirmed", all to be done while you are still at least 2+ miles out for your type of ops.

Yes, yes, before I get flamed, this is not hard unchangeable rules. When you hit 500 TT, then 1000 TT, then 3000TT , etc, etc, you will adopt your own risk tolerances for yourself

Sounds like what he was trying to say was that if you get an asymmetric flap condition while extending the flaps and rolling into a bank, you may not notice it in time to recover when you are low to the ground.

this term, while it does happen, is one of flight school, part 141 school, hangar talk lore. I have never personally seen this on a high wing Cessna, altho I have heard of them happening. I have never seen one tho.

I recommend return to basic aerodynamics and stall/spin concepts first.

another rule of thumb, dont force a plane to fly and dont force one to land. The plane will safely fly when its ready (V-R) and safely land when its ready (V-REF at 50 feet). It also needs XXX feet to safely do the above in. Yank it off early, land hot, "make it" stop in shorter than required field, and you will get away with it most of the time. However, make it a habit and it will bite you.

And don't try to abort a takeoff and hit the brakes on a flying airplane (past V-R). Its flying now. Don't try to force a plane to land if it's flying either (above V-REF). He11 yeah its floating, its still flying.

Oh yeah, gear UP once you are off the ground and airborne. Forget VSI-positive rate gibberish. Loose an engine while waiting on VSI and forget the gear and you may never get that magical positive VSI due to the down gear.

GEAR UP once you are airborne flying. You wouldn't be flying if you weren't positive rate.

Too many pilots these days simply drive airplanes, they dont fly them.

 

[Lead Sled]

I am just wondering if it is safe to apply a high degree of flaps while executing a turn to final at low speeds? I never heard anything about it being dangerous until today when a fellow pilot I know said it could cause a spin due to the assymmetry of simultaneously banking and extending all that drag out on the wing at approach speed. Just curious.

Flightjock30...

FWIW, I agree with Singlecoil's thinking. However, when it comes to aviation, it's probable not the best idea to use "absolute" words like always, never, etc. Before you make a blanket statement like the one your pilot buddy made you really ought to know what type of flap system you've got in the particular type of aircraft you happen to be flying. Some aircraft have connected flaps and short of a major structural failure it would be an impossibility for get a flap assymmetry. Others are indeed suseptable to a split flap condition and it can lead to a few "interesting" minutes. A point that I can a test to - I had it happen in a Cessna 340. Other aircraft, including most, if not all turbine-powered aircraft have flap (and where applicable, slat) assymetery protection that will stop the slats and/or flaps in their tracks if any assymetric condition exceeds a certain amount - typically around 3 degrees.

What's my point? You need to know and understand the system that's installed in the airplane you're flying. What could be an issue in one airplane is not a factor in another. (I don't wait until I've got the runway made to go to full flaps in aircraft like the Cessna 340 anymore. )

'Sled

 

[Flightjock30]

Thanks for the replies guys. A good pilot is always learning.

 

[PeteCO]

Flightjock30...

FWIW, I agree with Singlecoil's thinking. However, when it comes to aviation, it's probable not the best idea to use "absolute" words like always, never, etc. Before you make a blanket statement like the one your pilot buddy made you really ought to know what type of flap system you've got in the particular type of aircraft you happen to be flying. Some aircraft have connected flaps and short of a major structural failure it would be an impossibility for get a flap assymmetry. Others are indeed suseptable to a split flap condition and it can lead to a few "interesting" minutes. A point that I can a test to - I had it happen in a Cessna 340. Other aircraft, including most, if not all turbine-powered aircraft have flap (and where applicable, slat) assymetery protection that will stop the slats and/or flaps in their tracks if any assymetric condition exceeds a certain amount - typically around 3 degrees.

What's my point? You need to know and understand the system that's installed in the airplane you're flying. What could be an issue in one airplane is not a factor in another. (I don't wait until I've got the runway made to go to full flaps in aircraft like the Cessna 340 anymore. )

'Sled

Let's hear about that asymmetric deployment - what happened, how severe was the problem, how did you recover, etc. How much af a bank angle did you wind up at before you got the problem resolved?

 

[Ralgha]

I personally don't buy into the argument against extending flaps while in a turn. The possibility of an asymetrical deployment in a turn is the same as when out of a turn, and if you're in a turn, then there's a 50% chance that being in the bank will actually help you.