Flaps during Engine Out Landing

I don't mind the in my experience, unless it's being used to shut someone up because they've lost the argument, as in...

"In my 44 years of flying experience..."
"Yes, we get it, you're old and forgetful."
 
What about the scenario where you're having a really bad day and you've picked up a ton of ice during the descent and, dang it, your engine just died too. Flaps in or out?
 
sixpacker said:
What about the scenario where you're having a really bad day and you've picked up a ton of ice during the descent and, dang it, your engine just died too. Flaps in or out?
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Is the plane also on fire? And you might as well ask how you log it as well.
 
As I read this thread I see many "I was taught..." posters, and I salute those individuals for having chosen instructors who were perfect/knew everything and who decided never to investigate further anything those instructors taught them.

Looking back at my first logbook I have to say that my instructors (several, floats and wheels) were not perfect. As I gained experience and certificates/ratings I recognized that there are several ways in which an aviation task can be accomplished and that if I slavishly followed everything those early instructors taught (or failed to teach) my growth as an aviator would be limited.

As an instructor (not as a young instructor, BTW, but an experienced instructor) I tried to teach my students as many different ways to accomplish a task as possible, using every control (including the throttle/prop) as a tool.

Bob Gardner
 
It is all situational, I will stay clean until I have the runway made plus enough to account for the extra sink from the flaps, then I dial in flaps until my rate of descent is correct. If the reason I have lost the engine is fire, then I may modify that all the way to the point of not caring about making a runway. You can't make hard rules on anything like this, you can just consider what your options are and apply them to your situation as it arises to achieve best effect.
 
On negative flap settings:

Airfoils with camber create a negative (nose down) pitching moment when they create lift. Symmetrical airfoils, and reflex airfoils (where the trail edge curves back up) have zero pitching moment.

In something like a Maule with a high lift and high camber wing, they have a large nose down pitching moment. To counteract this, the tail must push down. The negative lift of the tail adds drag, and that extra downforce on the airframe requires extra lift of the wing, which adds more drag (anytime you make lift you make drag).

The reflex setting of the flaps get rid of that pitching moment, reducing the downforce required of the tail. This is a generalization, in some trim settings and W&B loadings, the tail may not be making downforce.

This is similar to why rearward CG conditions can improve the cruise speed of some planes. It reduces that downforce requirement of the tail compared to a forward CG.

I don't believe that the reflex flaps reduce induced drag. Induced drag is a function of CL, and at a particular cruise speed, the CL to stay airborn doesn't change. In fact, I would think it may increase induced drag to use reflex flaps, as this will change the lift distribution over the wing moving more lift towards the tips of the wing, which does increase induced drat. I may be wrong.


Reducing flaps to extend glide:

Flaps increase drag. If you aren't going to make the airport, I say get rid of some. I've yet to hear a scientific explanation of why reducing the flaps is worse than keeping in too much. Sounds like one of those instructor's tales to me.
 
If I need to stretch glide and I have flaps in, the flaps are coming out, I can always dump them back in at the bottom. Unless of course I'm flying a clap trap with hydraulic flaps, one pump, and it's on the dead engine. Then the calculation becomes trickier, because if dumping the flaps doesn't buy me the runway or landing spot I desire, I will be carrying a fair bit of extra energy into the crash. That's a tough call until you have about 100hrs in the plane and have the ability to judge your path in various configurations under a variety of conditions.
 
PilotRPI,

I had a lot of those same ideas - well put.

One other thought...

...would not the negative flaps, deflecting air UP instead of DOWN at the trailing edge and behind the CG, also cause a slight nose up moment which would have to be balanced by less tail down force? Also reducing total drag?

Does get confusing.
 
EdFred said:
There's the issue. Garbage in, garbage out. No offense Andrew, but you gotta verify what you've been told. Never take anything as fact/truth just because someone said so.
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No Hard feelings. :) I understand. Most of the instructors have either expressed their displeasure or are going to.
 
Instructor gets a "Failed" as well.
 
bobmrg said:
As I read this thread I see many "I was taught..." posters, and I salute those individuals for having chosen instructors who were perfect/knew everything and who decided never to investigate further anything those instructors taught them.

Looking back at my first logbook I have to say that my instructors (several, floats and wheels) were not perfect. As I gained experience and certificates/ratings I recognized that there are several ways in which an aviation task can be accomplished and that if I slavishly followed everything those early instructors taught (or failed to teach) my growth as an aviator would be limited.

As an instructor (not as a young instructor, BTW, but an experienced instructor) I tried to teach my students as many different ways to accomplish a task as possible, using every control (including the throttle/prop) as a tool.

Bob Gardner
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Bump. :yes:
 
bobmrg said:
As I read this thread I see many "I was taught..." posters, and I salute those individuals for having chosen instructors who were perfect/knew everything and who decided never to investigate further anything those instructors taught them.

Looking back at my first logbook I have to say that my instructors (several, floats and wheels) were not perfect. As I gained experience and certificates/ratings I recognized that there are several ways in which an aviation task can be accomplished and that if I slavishly followed everything those early instructors taught (or failed to teach) my growth as an aviator would be limited.

As an instructor (not as a young instructor, BTW, but an experienced instructor) I tried to teach my students as many different ways to accomplish a task as possible, using every control (including the throttle/prop) as a tool.

Bob Gardner
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:lol: If someone answers a complex subject with "I was taught..." I know they didn't have many instructors, because I don't know any subject that polling any 3 given CFIs won't produce at least 2 results.
 
The wandering of the thread into discussing the answers given, as if they were some kind of reflection on number of instructors or quality of instruction is hilarious horsepucky, typical of PoA.

People were answering the question asked. Most here have multiple instructors and experience in different operations. The original question asked a very specific question for a very specific, contrived false-emergency training scenario.

LOL. PoA is funny as hell. Parsing phrases like "I was taught" as if they mean something deeper than "here's the preamble to my answer" means a lot of people don't have in-person conversations much.

Yup "I was taught" on PoA means only one CFI, no experience, CFI worship, and all sorts of other ills. Maybe herpes too. ROFL.

Plus, the original question was WAY more interesting. Two instructors debating the ONE way to teach fake engine-outs. Heh. Think about that for a second. :)

Bob's right. Good instructors teach multiple techniques. The funny part is the PoA-esque assumption they didn't.

Here for the PoA weenies let me add:

"I was taught... [had to say it] to do whatever it took to put the airplane down in the safest location under control to ensure the survival of everyone on board."

Flaps, no flaps, inverted, whatever. Fly the damn thing and put it somewhere you can walk away.

The video a few years ago of the guys landing the LSA on the city street and taxiing into a parking lot works, when the feces stops the fan. No CFI is going to teach that technique or even act like its a reasonable training activity over a city during fake engine-outs. They did it and walked away.

An acquaintance on FB put one down on a Phoenix city street and dented a wing at night. Walked away too.

Fly the plane.
 
Get out of the big super structured schools and you'll find many instructors that recognize there are many ways to do something and could give a **** less which way you do.
 
Ok, here's my cents worth. Should be entertaining if not instructive. I was getting a BFR a few years back in my Grumman AA-5. the CFI was used to brand C or brand P, and had little or no experience in the Grumman single. We took off and climbed a bit, he put me under the hood, goofed around, slow flight etc, then he pulled the power and said 'engine out, set up for a safe landing'. I had it polished, and all fairings as tight as I could for reduced drag. I turned toward Hampton Roads as I was under the Norfolk C, and we had a nice westerly breeze. The CFI said 'what are you doing?' and I said; "I am going to glide to PVG and land the plane. He made a rather scoffing noise, and it was ON!

The speed was right on the best glide, and I made a call, 'straight in 27 Hampton roads'. We tootled along, nice a quiet, he asked if I wanted to 'clear' the engine and I said 'nah, we are fine'. Put the carb heat on and put in the flaps about 1/4 mile out. Landed just off the numbers and made the first taxiway. He was not a happy camper, lol.

I think the mistake in the OP situation was letting the flaps stay in from the moment the engine was failed. I would turn it into a teaching moment and ask the student his reasoning that he's giving up energy when the main source of energy was just turned off. hmmmmmmmmm? As for taking them out once they've been deployed, that is a 'it depends' situation. Does the pilot understand the relationship between clean stall and flaps stall? Are they going to get into a situation where removing the flaps deployed will put them in a stall/spin situation? I'm not a CFI so here's a spot where the training of a BFR would be useful when taken from a different instructor than the primary.

Oh, I 'passed' the BFR, and no herpes either. Woohoo.
 
My glider has 90 degree flaps and no spoilers, I often modulate the flaps up and down several times during the approach. Actually my technique is, point the glider just short of where I want to touch done and add or reduce flaps to maintain my 50kt appoarch speed.

In small power aircraft as long as you are in a steep stabilized approach reducing flaps will not significanly result in a loss of altitude but will increase the approach speed. Once you start to round out for the landing then don't mess with them, or use under 200 feet as a rule of thumb.

Brian
CFIIG/ASEL
 
FastEddieB said:
PilotRPI,

I had a lot of those same ideas - well put.

One other thought...

...would not the negative flaps, deflecting air UP instead of DOWN at the trailing edge and behind the CG, also cause a slight nose up moment which would have to be balanced by less tail down force? Also reducing total drag?

Does get confusing.
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It gets super confusing indeed! You learn a ton with an undergrad in aero engineering, but there is still so much to learn! Overall, the airfoil has to create some downwash in order to create lift. So I'm not sure the trailing edge of a reflex airfoil truly deflects air up.

With a cambered airfoil, the lift on the top of the wing is greater than that of the bottom, and is also located farther back, creating, the nose down moment (at positive angles of attack). By reflexing the trailing edge, you are increase the lift on the bottom of the wing, moving the lift vector of the bottom of the wing back equal to the point of the lift vector for the top of the wing, eliminating that moment. But overall, the air is still being deflected down from the wing.
 
On my PPL checkride, the examiner did an engine out (pretty windy day) and when he thought I had the field made, he announced he was putting in the flaps. Needless to say, I didn't think we were going to make and the second I knew we were coming up short, I pitched down and retracted the flaps. His response was good move, you got this. After that, he was very kind on the checkride, finishing it in about 30 minutes doing many of the maneuvers required in the pattern in only 3 laps... I was always "taught" to do whatever it takes to make the field...
 
FastEddieB said:
PilotRPI,

I had a lot of those same ideas - well put.

One other thought...

...would not the negative flaps, deflecting air UP instead of DOWN at the trailing edge and behind the CG, also cause a slight nose up moment which would have to be balanced by less tail down force? Also reducing total drag?

Does get confusing.
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My glider also has 10 degrees of negative flap. for those that are counting that is a 100 degrees of deflection from full negative to full positive flap.
Think of negative flap as lowering the angle of attack of the wing. So negative flap has a simlar effect as down elevator. It tends to lower the nose and increase the trim speeed. The main advantage is that at high speeds it lowers the induced drag of the wing.

Brian
 
I don't see why this couldn't have been a learning opportunity for the student.

Shouldn't an instructor be in the plane to teach and instruct? I suppose that's what that student was paying for. It doesn't sound like that's what was received.
 
DavidH said:
I don't see why this couldn't have been a learning opportunity for the student.

Shouldn't an instructor be in the plane to teach and instruct? I suppose that's what that student was paying for. It doesn't sound like that's what was received.
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Sounds like it might have been a part 135 stage check. A big reason I dislike Part 135.
 
denverpilot said:
LOL. PoA is funny as hell. Parsing phrases like "I was taught" as if they mean something deeper than "here's the preamble to my answer" means a lot of people don't have in-person conversations much.
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Oh to be the only smart one here. ;) It's fairly obvious which posts use "I was taught" as a throwaway, then continue to describe what they've learned from their actual experience trying different things. I don't see a whole lot of those. The problem is that a whole lot of pilots tend NOT to think about or try anything outside of what "I was taught". Many of their posts DO address issues with no more insight than "I was taught". That's where all this is coming from. Pilots need to break free of this mentality.
 
RoscoeT said:
Oh to be the only smart one here. ;) It's fairly obvious which posts use "I was taught" as a throwaway, then continue to describe what they've learned from their actual experience trying different things. I don't see a whole lot of those. The problem is that a whole lot of pilots tend NOT to think about or try anything outside of what "I was taught". Many of their posts DO address issues with no more insight than "I was taught". That's where all this is coming from. Pilots need to break free of this mentality.
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In a world where spins are not done even in aircraft fully capable of doing them safely, people are afraid of banking more than 30
degrees in the pattern, where all approaches must be "stabilized" as if we were flying Transport Category turbines, and entering midfield at pattern altitude without announcing your life story every ten seconds on the radio is considered "dangerous" at all times, and a slip is never better than full flaps dragging it in from three miles out?

ROFL. Sure. That'll happen...

That ship sailed a couple of decades ago.
 
denverpilot said:
In a world where spins are not done even in aircraft fully capable of doing them safely, people are afraid of banking more than 30
degrees in the pattern, where all approaches must be "stabilized" as if we were flying Transport Category turbines, and entering midfield at pattern altitude without announcing your life story every ten seconds on the radio is considered "dangerous" at all times, and a slip is never better than full flaps dragging it in from three miles out?

ROFL. Sure. That'll happen...

That ship sailed a couple of decades ago.
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Yeah maybe so. Assimilation is near total. :)
 
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