Stalls!!!

[ebykowsky]

By now, I'm more than comfortable with power-off stalls and love taking daring pax up for the oh so fun power ons, but the envelope on my comfort is really not very broad, and I'm not sure what is inoculant and what could kill me when my wings are stalled. First of all:
If a wing starts to dip: Use my rudder, not my ailerons. I know this, but using rudder opposite the wing dip could lead to a spin, right? At which point is it too much rudder and thus an uncoordinated stall that turns into something worse? At what point do I stop using aileron and switch to rudder (edit: I know to use rudder all along, I mean switch to exclusively rudder.)? A few seconds before the stall? At the buffet? Once it develops?
Another: I've been told a prompt break of the stall with a fast pushover. While this is done because it's good practice if I ever stall near the ground, can I just slowly nose over? As in slowly enough that I just feel a little light in the seat and not .5G?
Also, on the first question, how does the plane not risk a spin in the falling leaf stall? Isn't full rudder deflection used? I really want to know how far you have to go for a spin.
I plan on taking a CFI up for a little spin training and advanced stall training this summer--hopefully an hour or so will do. If you know anyone good in the SC area, let me know--I'd be willing to drive a couple hours. My FBO's aircraft is not spinnable as per insurance... I hate insurance limits.

 

[DutchessFlier]

Best advice I can give is to get ahold of your CFI and go up for a while and do them with the CFI and have he/she discuss them as you do them. A lot depends on what type of plane you are flying.

 

[Captain]

STOP doing stalls with pax!

 

[MAKG1]

Rudder opposite the dip is part of spin recovery, not spin entry. It's not a cross control because the ailerons are neutral and the elevator is released or pushed forward (that depends on model). PARE.

I've done isolated straight ahead power off stalls in a PA28 (very gentle) to prove to a passenger that the plane won't fall out of the sky and the wings will stay attached, but I wouldn't recommend doing it regularly or without significant prior discussion. You can scare the hell out of your passengers, particularly if you screw up.

 

[ebetancourt]

SNIP...A lot depends on what type of plane you are flying.

This is the crux of the matter. In my Citabria, a falling leaf is a piece of cake, in my Waco, not so much. One responds well to the rudder, the other requires lots of rudder and still doesn't respond well. On the other hand, the Waco really doesn't want to enter a spin, and will exit almost instantly without full pro-spin control input.

As far as an inadvertent spin, you are generally pushing on the rudder opposite the low wing, so a little more difficult to enter a spin. Slipping not skidding.

 

[ChrisK]

Slipping not skidding.

This is an important point =)

 

[ebykowsky]

One thing to realize is that my pax are mostly college aged guys. They love the feeling, and I do brief beforehand. If it's something I do solo, why not with a single passenger, so long as they're willing? If you guys think I'm putting their lives in danger with this then perhaps I should rethink my own sanity in doing them solo.

 

[Skip Miller]

STOP doing stalls with pax!

multiple choice question:

I am trying to:

1) Impress my pax as to what a good pilot I am (after only ___ hours of flying, too!

2) Scare the crap out of them so they never want to become pilots

3) both!

-Skip

 

[RoscoeT]

If a wing starts to dip: Use my rudder, not my ailerons. I know this, but using rudder opposite the wing dip could lead to a spin, right? At which point is it too much rudder and thus an uncoordinated stall that turns into something worse?

First, realize that a wing drop is unlikely to be an actual spin entry unless you are holding (and continue to hold) full aft elevator and full rudder. Most trainer types will not spin unless you fully deflect both controls and hold them. Lots of folks think a wing drop during a stall is an incipient spin...it's likely not. But since stall training these days teaches you to recover immediately, most don't let things develop to the point of seeing what is actually happening. Again, you can drop wings all day long during stall practice, but it's not likely going to be a spin unless you continue to hold full elevator and rudder.

Using opposite rudder to control a wing drop would only turn into a spin if you apply nearly full opposite rudder, hold it, keep the elevator aft, and hold these inputs to the point where the airplane breaks in the opposite direction. Using rudder during a stall is sorta like the rudder inputs used when handling a tailwheel airplane on the ground - quick input, then back to neutral. Don't apply lots of rudder and just hold it - you'll be overcorrecting, and probably end up in a worse situation than the simple wing drop you were trying to deal with initially.

At what point do I stop using aileron and switch to rudder (edit: I know to use rudder all along, I mean switch to exclusively rudder.)? A few seconds before the stall? At the buffet? Once it develops?

You should know when the airplane has stalled, and you should be able to feel when the airflow has re-attached to the wing after breaking a stall. Basically, don't use the ailerons when the yoke/stick is in your gut. The ailerons work fine up to the point of stall. Don't use them during a stall. But as soon as you push the yoke/stick forward, you've reduced the AoA and broken the stall. You can use the ailerons normally now, but your airspeed will be so slow that they'll be very ineffective. You don't need to wait until you've fully recovered to level flight after the stall to use ailerons again. You can use them as soon as you push the yoke/stick forward.

I've been told a prompt break of the stall with a fast pushover. While this is done because it's good practice if I ever stall near the ground, can I just slowly nose over? As in slowly enough that I just feel a little light in the seat and not .5G?

You can do it however you want, but the sooner and quicker you break the stall, the less altitude you will lose recovering the stall.

Also, on the first question, how does the plane not risk a spin in the falling leaf stall? Isn't full rudder deflection used? I really want to know how far you have to go for a spin.

If you are talking about the falling leaf where alternating rudder is used during the stall, a spin does not develop because you're basically doing a series of spin entries and immediate recoveries such that the airplane wallows back and forth, but does not develop into a spin. If you're talking about the 'falling leaf' that pilots may do in a Cessna during PPL training, you're only using enough rudder to keep the wings level. If those rudder inputs include full rudder deflection, as I mentioned before, you quickly remove that rudder input before the airplane breaks into a spin in the other direction.

And I would also agree that if your self-admitted comfort zone is narrow, then don't do this stuff with passengers. Get some spin training. Now. No need to put it off. You fly right? Well instead of going on a $100 hamburger run, you can fly your rental plane or whatever to someone who can give you some good spin instruction. It's not that time consuming or expensive in the scheme of things, and is the best training you can do. Not talking about you, but it's amazing how pilots will make excuses about it being "too expensive", "don't have time", or it's "too far away", blah blah blah. Bullsh!t. They are just making it a low priority, and are probably apprehensive about it. Pilots are also cheap bastards. Just do it. All your questions will be answered, and you'll have a lot more confidence. All the "stall prevention" training in the world don't do this for you.

 

[poadeleted20]

Bottom line here is that if you look inside at the ball when that wing drops, you'll see the ball is out to the side opposite to the dropped wing. This is because it is the yaw divergence skid which is causing the wing to drop. When you apply opposite rudder in this situation, you are correcting the skid, not inducing a slip, and it is the skid you are correcting which has the greatest potential to lead to a spin.

That said, from a safety perspective, I'd suggest having your instructor fly the plane to demo this while you look inside rather than trying it all by yourself with your eyes inside when they should be outside.

 

[RoscoeT]

Bottom line here is that if you look inside at the ball when that wing drops, you'll see the ball is out to the side opposite to the dropped wing. This is because it is the yaw divergence skid which is causing the wing to drop. When you apply opposite rudder in this situation, you are correcting the skid, not inducing a slip, and it is the skid you are correcting which has the greatest potential to lead to a spin.

That said, from a safety perspective, I'd suggest having your instructor fly the plane to demo this while you look inside rather than trying it all by yourself with your eyes inside when they should be outside.

I will respectfully submit that staring at the ball DURING a stall/wing drop/spin entry is a terrible practice. Totally pointless unless you are doing it once as a single training exercise to simply understand the dynamics better. Maybe you are framing this around upsets in IMC, but in general, you don't need to be (and should not be) staring inside the cockpit to figure out what to do with the rudder to recover a stall/wing drop/spin, etc.

 

[poadeleted20]

I will respectfully submit that staring at the ball DURING a stall/wing drop/spin entry is a terrible practice. Totally pointless unless you are doing it once as a single training exercise to simply understand the dynamics better. Maybe you are framing this around upsets in IMC, but in general, you don't need to be (and should not be) staring inside the cockpit to figure out what to do with the rudder to recover a stall/wing drop/spin, etc.

Exactly why I suggested doing it with a CFI flying the plane while you look inside, just so you can see what we've been talking about. After that, there is no need to look inside -- you will know that when a wing drops during a stall, it is caused by a yaw (skid) which is properly corrected with opposite rudder without worrying that you are creating, rather than correcting, a skid.

 

[bobmrg]

By now, I'm more than comfortable with power-off stalls and love taking daring pax up for the oh so fun power ons, but the envelope on my comfort is really not very broad, and I'm not sure what is inoculant and what could kill me when my wings are stalled. First of all:
If a wing starts to dip: Use my rudder, not my ailerons. I know this, but using rudder opposite the wing dip could lead to a spin, right? At which point is it too much rudder and thus an uncoordinated stall that turns into something worse? At what point do I stop using aileron and switch to rudder (edit: I know to use rudder all along, I mean switch to exclusively rudder.)? A few seconds before the stall? At the buffet? Once it develops?
Another: I've been told a prompt break of the stall with a fast pushover. While this is done because it's good practice if I ever stall near the ground, can I just slowly nose over? As in slowly enough that I just feel a little light in the seat and not .5G?
Also, on the first question, how does the plane not risk a spin in the falling leaf stall? Isn't full rudder deflection used? I really want to know how far you have to go for a spin.
I plan on taking a CFI up for a little spin training and advanced stall training this summer--hopefully an hour or so will do. If you know anyone good in the SC area, let me know--I'd be willing to drive a couple hours. My FBO's aircraft is not spinnable as per insurance... I hate insurance limits.

No. You want to feel the lap belt holding you down in your seat and the horizon about 1/3 to 1/2 way up the windshield. This is not the time to play pattycake, it is survival time. You won't feel light in your seat if you relax back pressure slowly or gingerly. This is a real failing in today's training. You might recall the Colgan accident in Buffalo, during which the captain followed his training and tried to minimize altitude loss...but he lost that battle and the airplane/pax. Among the NTSB findings was a recommendation that "minimum loss of altitude" be removed from test and training standards.

Bob Gardner

 

[JHW]

so basically, your view is that it's a good idea to demonstrate a maneuver for passengers, which you yourself are so unsure about that you seek out advice from anonymous people on the internet as to how to avoid killing yourself and your passengers?

 

[RV10flyer]

I practice stalls at full gross with my family a few times throughout the year. I rarely fly solo and our plane reacts much differently at gross/rear CG. During phase 1 testing, I practiced with 450 lbs of dogfood. My family knows the importance of stall training. We stay above 2,000 AGL. I don't practice them with anyone else on board.

 

[Captain]

One thing to realize is that my pax are mostly college aged guys. They love the feeling, and I do brief beforehand. If it's something I do solo, why not with a single passenger, so long as they're willing? If you guys think I'm putting their lives in danger with this then perhaps I should rethink my own sanity in doing them solo.

Since they're college aged they won't mind dying???

Look, you admitted you're not good at the maneuver. Others have pointed out the maneuver can kill you if done wrong. You were taught stall so you would avoid them and know what to do if you screw up and find yourself there.

Just please stop doing them with pax. You are the PIC and need to make smart choices. Stalling with them with your experience isn't smart.

 

[ChrisK]

Among the NTSB findings was a recommendation that "minimum loss of altitude" be removed from test and training standards.

Oh that's interesting. So the focus should be on "proper corrective action" rather than "minimum loss of altitude". I assume that "proper corrective action" is subjective, which is why the other standard was there in the first place.

 

[gismo]

Since they're college aged they won't mind dying???

I think the point you're missing is that at "college age" they're still immortal.

And I agree that stall practice isn't something I think a pilot should be demonstrating to non-pilots except perhaps when the pilot is very comfortable with the airplane and the pax specifically wish to experience this.

 

[gismo]

No. You want to feel the lap belt holding you down in your seat and the horizon about 1/3 to 1/2 way up the windshield. This is not the time to play pattycake, it is survival time. You won't feel light in your seat if you relax back pressure slowly or gingerly. This is a real failing in today's training. You might recall the Colgan accident in Buffalo, during which the captain followed his training and tried to minimize altitude loss...but he lost that battle and the airplane/pax. Among the NTSB findings was a recommendation that "minimum loss of altitude" be removed from test and training standards.

Bob Gardner

I pretty much agree except for the attitude (i.e. horizon about 1/3 to 1/2 way up the windshield). The sooner you unload the wing, the sooner it will be below the critical AoA and AoA is what it's all about. Ideally you should pitch for best rate AoA as quickly as possible and then hold that AoA. Unfortunately without an AoA indicator it's rather difficult to determine the pitch attitude necessary for that and any specific pitch attitude is going to be wrong more often than right.

 

[gismo]

Bottom line here is that if you look inside at the ball when that wing drops, you'll see the ball is out to the side opposite to the dropped wing. This is because it is the yaw divergence skid which is causing the wing to drop. When you apply opposite rudder in this situation, you are correcting the skid, not inducing a slip, and it is the skid you are correcting which has the greatest potential to lead to a spin.

I think you've said before that as long as you prevent the airplane from yawing (e.g. with rudder) it will not spin and I believe this to be true regardless of whether the airplane is skidding or slipping (but your explanation that a wing drop implies a skid makes some sense). IMO, rudder is most useful for preventing yaw because it always works the same way WRT yaw unlike the ailerons which don't.

 

[RoscoeT]

If, despite the recommendations against, someone lacking skill and comfort with stall/spin entries insists on practicing power-on stalls with passengers, here is how to prevent a spin: No matter what, keep the dang rudder and ailerons neutral through the stall. Forget keeping the ball in the center...yes that's right. Sure, you will probably drop a wing during the power-on stall, but you will NOT spin. When the airplane stalls, pull the power off and return the elevator to neutral, while continuing to hold neutral rudder and aileron. When your airspeed has increased a little, use aileron to level the wings, and return to level flight. NOTE: This is NOT the most efficient means of recovering from a power-on stall...far from it. But you will NOT spin if you do this. I don't even recommend people really go out and do this...just an FYI for inexperienced pilots who are going to do things on their own with pax anyway.

And BTW, you can recover from just about any upset in just about any airplane by using this technique - including an inverted power-on flat spin in a Pitts. Power off, all controls to neutral, wait for the airplane to start flying again, and pull out. This is no replacement for training. Just a way to reduce the chances of someone monkey-footing the rudder and entering their first spin either by themselves, or with a non-pilot passenger. I've known people to enter accidental spins by playing around with power-on stalls. It's ALWAYS because they either used opposite aileron to try to control the wing drop (bad), or used too much opposite rudder, overcorrecting the other way. Nobody gets into a spin by undercontrolling.

 

[ebykowsky]

Thanks for the responses, some very helpful info. As far as the people who say I shouldn't be doing them with pax, OK I hear you. But I've only done this a grand total of 3 times with 3 different people, the first two with CFI onboard, and the last was interested in the aerodynamic aspect of stalls and wanted to understand why they aren't so dangerous as many believe. We did a total of 2 on that flight, one power on one off, after demonstrating what the break would feel like through a pushover in an unstalled condition. I agree that I need more training, and like I said, I want to get that this summer (which starts in 3 days for me). I really don't think taking pax up is that big of a deal if I can do the maneuvers solo, and if I am really in that much danger (as much as you imply I might be at my current aptitude) then I don't even want to be doing them solo; I don't see them as a stupid pilot trick but rather a necessary maneuver, commensurate to a steep turn. Within my envelope, which admittedly is not broad, I feel very confident with stalls. However, while I do understand that trainers are quite forgiving, if at any moment during the maneuver I felt uncomfortable, I would have knocked it off.

 

[ChrisK]

commensurate to a steep turn

Something else I probably wouldn't do with a non-pilot passenger =)

 

[poadeleted20]

If, despite the recommendations against, someone lacking skill and comfort with stall/spin entries insists on practicing power-on stalls with passengers, here is how to prevent a spin: No matter what, keep the dang rudder and ailerons neutral through the stall. Forget keeping the ball in the center...yes that's right. Sure, you will probably drop a wing during the power-on stall, but you will NOT spin.

Sorry, Roscoe, that's not true. Lots of things can cause an aircraft to yaw at the stall besides aileron or rudder inputs, and in the right plane, those can definitely result in a spin even with ailerons and rudder neutral. True, in the average light single trainer, the airplane will not spin without positive pro-spin controls. But if you teach it like that in that average light single trainer, you establish a pattern which can be negatively transferred to more aerodynamically sophisticated aircraft. The key in this context is to use rudder to keep the plane from yawing (which means the ball stays centered) as the stall is approached, and if you do that, the wing won't drop and the plane won't spin, and the pattern is established for when that person later on starts losing one in a twin, or flies a swept wing aircraft.

 

[RoscoeT]

Sorry, Roscoe, that's not true. Lots of things can cause an aircraft to yaw at the stall besides aileron or rudder inputs, and in the right plane, those can definitely result in a spin even with ailerons and rudder neutral.

Well I would pay good money for an in-person (or video) demonstration of a spin that develops while holding neutral aileron and rudder, pulling power off at the stall, and neutralizing the elevator. If there are airplanes out there that will actually do this, I would like to know what they are, and would also BET good money that you sure wouldn't be willing to demonstrate this in said airplane. I guess I'm talking about airplanes with known (and safe) spin characteristics. I'm not talking about a 310 with full tip tanks. If these are the kinds of airplanes you're talking about then you're probably right. I'm talking light singles, trainers, sportplanes, and aerobatic airplanes. And again, I'm not recommending people actually go out and do this in their Baron, just that the weekend bugsmasher out flying a Cessna or Piper trainer will NOT spin if they do as I describe. But forget all this, just get good stall/spin training, and don't do anything the airplane is not suited for.

 

[RV10flyer]

When the stall occurs that will kill you it won't be at 3000' AGL, intentional, your stall horn will not go off soon enough or you may not even hear it and you won't expect it. It will happen on short final, right after takeoff or on the go around from a short strip You'll be distracted and will need to make an immediate and proper corrective action when the winshield is full of Earth. The only way to develop that reflex is with practice. 85% of the stall/spin accidents involve a climbing turn. Practice your climbing, turning stalls up high until it becomes instinctive. My wife does not like the practice as much as my kids but knows the importance. After much practice you should be able to feel when you need to unload the wings. For me it is a combination of stick feel, airframe vibration, sight picture, sinking feeling and airflow noise. We practice the sterile cockpit rule and my wife pays very close attention to airspeed. She or my stall horn has not had to warn me during any landings or takeoffs yet.

 

[bobmrg]

Oh that's interesting. So the focus should be on "proper corrective action" rather than "minimum loss of altitude". I assume that "proper corrective action" is subjective, which is why the other standard was there in the first place.

You have to get the boundary layer re-attached to the wing as quickly as possible, altitude be damned. Until the whole wing is flying again, you are not truly in control.

Insofar as "the other standard" is concerned, there is a Docket up for comment right now (comments end May 24) that, if adopted, will make major changes in training and testing....and this is a target area.

Bob

 

[jnbcfi]

If you choose to get some spin training make sure you do it in an aerobatic trainer with chutes, not your normal or utility category airplane. Chutes are required unless you are training for a CFI Practical Test. See FAR 91.307 (c),(1),(2); (d),(1),(2).

 

[ebykowsky]

Unfortunately the nearest place I could find didn't list prices but they use a Stearman, and I'm not about to pay for that. I really wouldn't mind using a 172 since that's what I'm comfortable with--i don't need flips or anything crazy.

 

[wabower]

After reading Sparky's book and discussing the subject with him a few times I'm convinced that a centered ball isn't always the answer, especially in high-wing Cessnas. Sparky says a half-ball right will result in wings-level recovery, which jives with the fact that the 172 we owned to train friends and kids would drop a wing with centered ball.

Sorry, Roscoe, that's not true. Lots of things can cause an aircraft to yaw at the stall besides aileron or rudder inputs, and in the right plane, those can definitely result in a spin even with ailerons and rudder neutral. True, in the average light single trainer, the airplane will not spin without positive pro-spin controls. But if you teach it like that in that average light single trainer, you establish a pattern which can be negatively transferred to more aerodynamically sophisticated aircraft. The key in this context is to use rudder to keep the plane from yawing (which means the ball stays centered) as the stall is approached, and if you do that, the wing won't drop and the plane won't spin, and the pattern is established for when that person later on starts losing one in a twin, or flies a swept wing aircraft.

 

[gismo]

If, despite the recommendations against, someone lacking skill and comfort with stall/spin entries insists on practicing power-on stalls with passengers, here is how to prevent a spin: No matter what, keep the dang rudder and ailerons neutral through the stall. Forget keeping the ball in the center...yes that's right. Sure, you will probably drop a wing during the power-on stall, but you will NOT spin. When the airplane stalls, pull the power off and return the elevator to neutral, while continuing to hold neutral rudder and aileron. When your airspeed has increased a little, use aileron to level the wings, and return to level flight. NOTE: This is NOT the most efficient means of recovering from a power-on stall...far from it. But you will NOT spin if you do this. I don't even recommend people really go out and do this...just an FYI for inexperienced pilots who are going to do things on their own with pax anyway.

And BTW, you can recover from just about any upset in just about any airplane by using this technique - including an inverted power-on flat spin in a Pitts. Power off, all controls to neutral, wait for the airplane to start flying again, and pull out. This is no replacement for training. Just a way to reduce the chances of someone monkey-footing the rudder and entering their first spin either by themselves, or with a non-pilot passenger. I've known people to enter accidental spins by playing around with power-on stalls. It's ALWAYS because they either used opposite aileron to try to control the wing drop (bad), or used too much opposite rudder, overcorrecting the other way. Nobody gets into a spin by undercontrolling.

That may (or may not) be true in the typical trainer but I've flown a few airplanes that will depart into a spin with the controls held in the center. One is an AT-6 and another is the StardusterToo.

 

[gismo]

After reading Sparky's book and discussing the subject with him a few times I'm convinced that a centered ball isn't always the answer, especially in high-wing Cessnas. Sparky says a half-ball right will result in wings-level recovery, which jives with the fact that the 172 we owned to train friends and kids would drop a wing with centered ball.

I think it makes sense that engine torque (p-factor etc) would make the airplane slightly uncoordinated with the ball centered.

 

[somorris]

Hi Ebykowsky.

Be real careful. What you are doing could get you into trouble. Bill Finagan is on the east coast and could give you the type training you need to keep from getting into trouble. Go to the International Aerobatic Club's website and look at aerobatic schools and get some training. There may be somebody closer to you.

 

[John221us]

I have flown with Ebykowsky and he is a safe pilot and a good stick. I will echo that stalls and steep turns with pax are not a good idea, though.

 

[ebykowsky]

I have flown with Ebykowsky and he is a safe pilot and a good stick. I will echo that stalls and steep turns with pax are not a good idea, though.

Thanks, John.
Are you guys mainly saying this about not doing these with pax because they endanger another life or because they could freak the person out? Or because they could mess up the maneuver somehow?

 

[JHW]

If you choose to get some spin training make sure you do it in an aerobatic trainer with chutes, not your normal or utility category airplane. Chutes are required unless you are training for a CFI Practical Test. See FAR 91.307 (c),(1),(2); (d),(1),(2).

not in the real world. Hold your nose right and everyone can be training for the cfi, they just elected to start with the spins

 

[John221us]

Thanks, John.
Are you guys mainly saying this about not doing these with pax because they endanger another life or because they could freak the person out? Or because they could mess up the maneuver somehow?

It comes down to spooking the passenger. I know at that age everyone is immortal, but the end result may be different. If the pax is a certificated pilot, I have no issue with any maneuver, but a first time flight should be a fairly passive enjoyable experience, not an e ticket ride. I have heard a few stories from people that have been cured of ever flying again by a friend taking them on such a ride. It seems a shame.

 

[jnbcfi]

not in the real world. Hold your nose right and everyone can be training for the cfi, they just elected to start with the spins

Holding your nose is right. Advising to wriggle around the regs stinks.

 

[poadeleted20]

If you choose to get some spin training make sure you do it in an aerobatic trainer with chutes, not your normal or utility category airplane. Chutes are required unless you are training for a CFI Practical Test. See FAR 91.307 (c),(1),(2); (d),(1),(2).

If you read those regs carefully, you'll see that you do not have to be in training for that particular certificate/rating, just doing a maneuver which is required for a certificate/rating. This was asked and answered by the Chief Counsel some years back. So, you can do spins even with a Student Pilot without chutes. Further, the spins need not be done in an aerobatic trainer, just an aircraft approved for intentional spins, which includes Cessna 150/152's (mind the AD on that) and Cherokee 140's (but not Warriors). Of course, you may learn a lot more about spins in planes which do not require such strong pro-spin controls for entry and which do require positive anti-spin controls for recovery, but that's another story.

 

[wabower]

It's like DK Royal said about throwing the football. Three things can happen, two of them are bad. Why do it?

Thanks, John.
Are you guys mainly saying this about not doing these with pax because they endanger another life or because they could freak the person out? Or because they could mess up the maneuver somehow?