Bank Angle In The Circuit

[Colonel Sanders]

Longtime readers of AvCan will cringe now and stop reading.

A pet peeve of mine for many, many years is what horrible
nonsense flight instructors in Canada teach their students
about bank angle in the circuit.

Decades ago, someone (long since retired, or dead) noticed
that as bank angle increased, so did stall speed. So, to avoid
stall/spin in the circuit, it was announced with near-religious
fervor that henceforth minimum bank angle would be used
in the circuit. Great celebrations followed, with banquets
and awards, and not just the cheesy ribbons - I'm talking
metal and wood trophies.

Small detail. It is only true that stall speed goes up with
bank angle if you are pulling more and more G which is
a result of a LEVEL turn with the BALL IN THE CENTER.

For example, I can safely turn base in almost any aircraft
at 60 degrees of bank (ok, 59.99999999 degrees) at
slow speed as long as the G is very light - the wing is
not working, and hence has a low angle of attack) and
especially if I sideslip.

Remember, slips are good. Skids are bad. I will frequently
use 90 degree sideslip on short final to kill energy, and
my aircraft does NOT explode with infinite G as your
ab initio instructor taught you, because the ball is not
centered, and I am not maintaining altitude.

The above is really important to understand.

Anyways, I was flying with another victim of our flight
training establishment yesterday. He would turn base
with a very shallow bank angle as he was taught, but
unconsciously, to speed up the turn, he would hoof
the inside rudder (a skid) and then as the inside wing
dropped due to loss of lift, try to pick it up with aileron
creating more adverse yaw, which of course aggravates
the spin entry.

He really didn't want to enter a spin turning base or final,
he was just doing what generations of unthinking flight
instructors have parrotted down through the decades -
keep the bank angle low.

This is all totally and completely wrong.

What matters in the turns is NOT keeping the bank angle
low, but maintaining airspeed and keeping the ball centered.

I have a mantra for light trainers for maneuvering in
turns after downwind, until wings-level on final:

80 and ball

If you maintain 80 mph with the ball centered, you can
use 60 degrees of bank during turns onto base and final
without stalling or spinning. Check your POH. This is
helped by the fact that you are NOT trying to maintain
altitude during these turns.

Most people are very very uncomfortable with excessive
bank angle in the circuit - they will NOT willingly use 60
degrees.

But the good thing about bank angle is that YOU CAN SEE
IT! You often can't see a nasty skid unconciously caused
by inside rudder - see Illusions Created by Drift.

So please, flight instructors in Canada, break the cycle. Stop
teaching your students to fly dangerously and badly. Bank
angle in the circuit is NOT evil - what's evil are skids!

[coreydotcom]

What matters in the turns is NOT keeping the bank angle
low, but maintaining airspeed and keeping the ball centered.

This is what I was taught. I would say I generally use about 20 degrees of bank (so I guess shallow) because that is what feels comfortable. I have never experienced 60 degrees of bank yet, but I also don't have 15 hours in my logbook yet.

If I understand correctly, the point of the post to highlight that you CAN use high degrees of bank? Is there anything wrong with not using a high bank angle when turning base/final? Especially for an extremely low-time guy like me, it just seems a bit "sportif" of a move to be doing at that point in time in the flight (but then again, I guess that's relative, because I have precisely 0 60 degree banks under my belt).

Thanks,

[jump154]

I was stunned at Oshkosh during Rod Machado's "Stick and Rudder" seminar that someone asked at the end for a comment on the instruction he had been given to "Not use the rudder in the circuit". Rod set him stright, and kudos for asking the question but it made me shudder that someone is teaching that stuff. Maybe I know more about this flying lark than I realised?

[Colonel Sanders]

you CAN use high degrees of bank?

Yes, yes! (jumping up and down, excited).

Turn an aircraft by using bank - not by yawing it flat.

Yawing an aircraft flat at low speed and low altitude - which
is what the flight training establishment in Canada teaches -
is extremely dangerous because of the high probability of
a spin entry. Please leave that to the very best airshow
pilots, like Rob Holland.

What's important in a turn is actually angle of attack.

Don't stall the wings. In the absence of an angle of
attack indicator - you actually need two, one for
each wing - you can avoid stalling in a turn by:

1) avoiding a skid (slips are good, skids are bad)
2) maintaining airspeed
3) keeping the G loading light

Notice that bank angle doesn't even make the top three.

Note that I will happily fly with 90 degrees of bank at
zero airspeed without stalling the wings when I perform
a hammerhead pivot!

Again, angle of bank is NOT evil. Understand the relative
airfow over the wing and all will be revealed!

[schmoo]

Personally, I was taught to keep bank angles no bigger than 30 degrees in the circuit, BUT was definitely never taught to hurry up a turn in the circuit with rudder. Ensuing conversations and my own musings concluded that the reasons for keeping bank angle on the 'lowish' side was not so much as to avoid stalling in the circuit, but for other reasons such as :

-large bank angles temporarily reduce visibility at a time when watching for other aircraft is paramount
-new pilots are busy monitoring a myriad of more important things like airspeed, maintaining circuit altitude, wind, landing procedures, etc
-steep turns in the circuit are not necessary for the types of planes most newbies are flying. Better to plan for drift in the turns.

Regarding the "stick and rudder" seminar and the instruction that students not use the rudder in the circuit, how risky is this ? What percentage of turns would be skidding turns if the rudder is ignored ? Wondering if instructors figure that more skidding might occur in the circuit if students are constantly attempting to centre the ball and possibly over-correcting.

[frog]

Colonel

One little comment : I understand what you are saying but, encouraging students to perform a 60 degree bank angle turn in the circuit could lead to other problems as excessive nose down, speed increasing etc...it would need a different approach in initial training.
Also I think that saying that instructors are taught to teach students to skid the plane in the circuit is a bit of a stretch.

[FenderManDan]

My instructor (the second one) kept it simple in the circuit and it worked fo me. He just said keep an eye on the ASI 70 mph and aim the numbers. Its amazing how quickly everything else followed. When I became comfortable i looked in the ball and guess what, it was centered. He only warned me of steep turns on the climb and turn on crosswind leg, i stopped looking at the bank indicator rally and just simply flew it where it needed to go. .

[Colonel Sanders]

encouraging students to perform a 60 degree bank
angle turn in the circuit could lead to other problems

Heh. People won't fly 60 degree banked turns in the circuit -
they find that frightening and will avoid it, which proves my
point - bank angle in the circuit isn't a problem.

I am trying to make the point that flying a 60 degree banked
turn in the circuit is much less dangerous than what you are
teaching your students.

saying that instructors are taught to teach students to skid
the plane in the circuit is a bit of a stretch.

Nope - flight instructors in Canada teach students how to fly
the circuit in such as way as to result in them flying slow, flat
skidding turns with adverse yaw which results in stalls and spins
in the turns to base and final. You think that's a good thing, so
keep on doing what you're doing. But you're part of the problem.

[coreydotcom]

Colonel: you stated in huge letters and bolded : "80 and ball".

So my instructor taught me 70 (kts) and ball, i.e., the exact same thing you just said.

You're just making it seem that flying shallow turns in the circuit is bad (sorry if that's not your intention - I get the point, you CAN bank hard and there's no problem with that) and I just want you to clear up whether you think it is. With my less than 15 hours I don't see a problem of doing shallow banks, with the ball centered (and now, I guess I don't see the problem with doing steep banks, with the ball centered)... am I wrong?

Also, right now in my training I am asking to practice the slip a lot and I am getting more and more comfortable with it (as much as you can in 15 hours). The slip feels like (and is) a controllable maneuver. The skid just absolutely doesn't feel right at all... it feels like you're going to induce a spin (which you will eventually). When would a skid be appropriate... it seems like never is the right answer...

[Colonel Sanders]

The problem is .... people don't intentionally skid. They
don't wake up in the morning and say, "When I turn base
today, I'm gonna give it full inside rudder!"

The insidious thing is that people don't even know they
are skidding. They just want to turn the aircraft, and since
their instructor tells them they can't turn with bank, they
subconciously press on the inside rudder to increase the
rate of turn. Then, the inside wing starts to lose lift because
it has slowed down, so they then try to pick it up with aileron
which creates adverse yaw which makes the problem worse.

Ah, the irony. Instructors try to have their students avoid
stall/spin by keeping the bank angle down, and as a result
make their students skid through their base and final turns.

Over and over and over and over I have had to explain to
pilots that what they are doing is very dangerous - a flat turn
at slow speed at low altitude. And, they don't even know
that it's a very high risk maneuver - they are astonished to
realize they are punching the inside rudder, and trying to pick
up the downgoing inner wing with aileron.

I can't think of a better way to enter a spin. And I find it curious
that people have no problem with entering spins at 500 AGL.

I guess the difference is that I think a slow, skidding flat turn is
worse than a co-ordinated (or slipping) steep turn with airspeed
and no G load.

[CpnCrunch]

I understand what you are saying, but there are other ways to kill yourself in the circuit. In a cessna 172 the full-flap stall speed is 59mph in a co-ordinated, level, 45-degree turn (if my calculations are correct). With 20 degrees of flap, it will be higher. If you're not paying attention to your airspeed it's possible you could get close to the stall in a steep turn.

[frog]

I used to be an instructor and I remember my instructor course and I remember clearly that we were expected to make sure that students will fly coordinated furthermore at low altitude. I think there was an exercise about that actually, something like illusion (if my memory serves me well)
So i understand our point as to avoid skid in order to cross control stall and eventually spin the aircraft.
But again I think you are going to far in your reasoning.

[iflyforpie]

I used to think high banks angles were harmless, until I saw a 172 in the circuit the other day doing a 60 degree bank. A gust of wind caught him and he went to 90 and there was an explosive shower of aluminum dust, fuel, and oil that just managed to escape the event horizon of the singularity created by the infinite number of Gs. Not since I penciled in a zero on the center scale of my E6B had I seen such a sight....

[Colonel Sanders]

he went to 90 and there was an explosive shower of aluminum dust

Happened twice here last week.

[Shiny Side Up]

The problem is .... people don't intentionally skid. They
don't wake up in the morning and say, "When I turn base
today, I'm gonna give it full inside rudder!"

To me though the problem isn't the reccomendation to plan a circuit with shallow bank angle turns, but starts far before that in the basic climbs/turns/descents lesson. If a student can't get the idea of how the ball works by the end of it, then they shouldn't be progressing past it, but often they do in a race to get to the circuit. It should be of little suprise then that they don't do coordinated turns when they get to the circuit, which I think should be the stressed point of the colonel's complaint. Add a second factor in here and that is often the very little time spent by many instructors on the illusions created by drift lesson, which again should be a precursor to the circuit, but often isn't, by the gross ammount of PTRs I've went through. I will say it takes nothing short of the occasional beating to get even my own people to take the propper time on these lessons too so that we don't produce pilots that upset the Colonel. Lastly, many don't spend a lot of time doing slips before the circuit, which for some reason I seem to be in the minority where I feel they are of critical importance. I doubt many learn the simple axiom slips good, skids bad but rather think that they are equally bad (and I'm aware there are a lot of people in TC who feel that way as well) consequently they don't know the difference.

In flight training there is a big push to get into doing those crash and dashes and a lot of students skills suffer because of it.

[ross1]

From the Transport Canada Flight Instructor Guide....

"(4) If the student has difficulty in judging the final turn into wind,insist on a shallow banked turn. The slow rate of turn allows more time for judgement, and bank can be increased or decreased as necessary."

...maybe turns deserve more work before the circuit.

[Colonel Sanders]

slips good, skids bad

This is really important for the student (and likely many private)
pilots to learn!

Centering the ball is nice because it is minimum drag. This allows
you to get maximum climb rate, for example. Most people like
to climb out in a sideslip after takeoff, using the side of the fuselage
as a drag device to reduce the aircraft climb performance. Don't do
that. Use right rudder to center the ball.

Centering the ball also feels good. Although cars turn flat, bicycles,
motorcycles and airplanes incline during turns, so that all the forces
are vertical. Maybe I'm getting old, but my back hurts after an hour
of flying with the ball fully deflected. If you intend to ever fly anything
with more than a few seats, you will give the people in back a wild
ride with the ball sloshing back and forth.

Now onto turns. During a turn, the ball can be:

1) centered, which feels good with minimum drag, or

2) falling to the inside of the turn, which is a sideslip,
which creates drag and is a great way to lose energy, or

3) climbing to the outside of the turn, which is a skid
which usually results from too much "inside" or bottom
rudder application. This is dangerous if the speed bleeds
off, because the inside wing is slowed down, produces
less lift, and can even stall during a descending turn (eg
onto base or final) which results you being upside down
in a spin at 1000 or 500 AGL, which you likely will not
survive.

To summarize:

- ball centered is usually good. Minimum drag, good
pax comfort, and less likely to stall/spin

- sideslip is good during turns. Creates drag if you
are high. Can use to dissipate energy if you don't
have flaps, or don't want to/can't deploy any more
drag devices. Ball falls to inside of turn. Caused by
application of top or outside rudder.

- skids are always bad. Don't do this. Danger of inside
wing stalling. Ball goes to outside of turn. Caused by
application of bottom or inside rudder, often to increase
the turn rate with insufficient bank.

Maybe I'm living on another planet, but the above is not
rocket science. It does not require the use of Kalman
filters or Special Relativity and MUST be understood by
anyone who ever wants to be the sole occupant of an
airplane.

I do not understand why such simple, fundamental
knowledge is not taught. Compared to all the nonsense
that is thrown at student pilot, the basics of how an
airplane turns should really be taught.

[xysn]

Longtime readers of AvCan will cringe now and stop reading.

I think if "Stick and Rudder" were required reading and understanding you wouldn't have needed to post this. Over and over it's written - banks make the turn. Not rudder.

For my own learning I noticed that the adverse yaw in my training type acts such that I don't need to use left rudder doing a gentle roll, rather that only a reduction in right rudder pressure was needed. Conversely on right rolls more right rudder pressure was needed. Once I figured it out I dimly remembered that my instructor had mentioned this in a PGI once ...

Bank angle in the circuit is NOT evil - what's evil are skids!

I think I would simply emphasize the fundamentals - banks make the turn, not the rudder. The rudder in no way "hurries" the turn. I suppose, while flying straight and level, if you just booted a rudder a bank and turn would follow, in the same way that setting your couch on fire would heat your house?

If you are turning too slow, bank more. If you're still turning too slow, use the steep turn procedure. If steep turns are a bad idea in the circuit, next time, turn sooner or fly a wider pattern.

Anyways, I was flying with another victim of our flight training establishment yesterday

On the bright side, at least I feel like I'm getting some decent instruction since I don't think I have these habits ...

[Shiny Side Up]

I do not understand why such simple, fundamental
knowledge is not taught.

I assume you're being facetious here to me its really quite simple why its not being taught and that's because its not deemed important by both instructors and students. Here's what is viewed as important, to quote yourself:

That will save you money and help you go solo in minimum
hours, which is nice.

Now I'm bending your words to my purposes, but a lot of people would take what you said there at face value in that what's important in your training is getting to solo fast, which often results in the above. New students unfortunately don't usually see the connection between lnading the airplane (which they view as the most important thing to learn) and being able to make coordinated turns (which they view as considerably lesser importance) and how to use a slip purposefully (which is viewed as even less). Cost wise as well, soloing quickly is for the most part irrelevant as I find that students who spent more time on the basics before rushing to the circuit tend to finish their licenses in closer to the minimum ammount of time (the all important 45 hours) than students who spent less time on them and soloed quick, but then took more work to get to be test ready. Suffice to say, more students just need more time flying the damn airplane to get good at it and less time doing stuff which interests the instructor more.

[Genetk44]

Colonel I think you should be instructing.

[Colonel Sanders]

Thank you, but I don't do as much instructing as I used to.

Just checked my logbook, in the last week I only did eight
instructional flights, which isn't much for the summer months.

I teach the odd advanced student - I qualified an ICAS ACE for
airshow formation aerobatics at the friday waiver at the
Geneseo airshow a couple weeks ago - and I take on a new
instructor candidate every now and then, but that's about it.

It's nice to get a little stick time myself every now and then.

For example, this was a slowed-down 260 knot "banana"
photo op top pass at an airshow I flew a while back:



My friends all hooted and hollered like a bunch of chimpanzees
at that photo - note the top rudder to do a level sideslip turn
to get more bank on for a better picture from the ground, of
the top of the airplane?

Jet pilots don't sideslip! Jet pilots NEVER use the rudder!

Well, they do if they're cranky old airshow pilots

[iflyforpie]

I think I would simply emphasize the fundamentals - banks make the turn, not the rudder. The rudder in no way "hurries" the turn. I suppose, while flying straight and level, if you just booted a rudder a bank and turn would follow, in the same way that setting your couch on fire would heat your house?

Rudder indeed can hurry the turn... just as opposite rudder can stop the turn. It's not very effective, but it does nonetheless. I do 'boat turns' using solely rudder with opposite aileron for photography purposes all of the time. It is technically a skid, but with enough speed and altitude it isn't dangerous.

The reason it increases or decreases turn rate is because of the horizontal body angle of the fuselage, which can create small amounts of horizontal lift. This is the same force that causes so much drag in a side slip (the 'lift' prevents you from spiraling.... you can get the same drag from a skid, but the lift will push you down... not really recommended!).

[AOW]

I used to think high banks angles were harmless, until I saw a 172 in the circuit the other day doing a 60 degree bank. A gust of wind caught him and he went to 90 and there was an explosive shower of aluminum dust, fuel, and oil that just managed to escape the event horizon of the singularity created by the infinite number of Gs. Not since I penciled in a zero on the center scale of my E6B had I seen such a sight....

Post of the year!

[Big Pistons Forever]

To me though the problem isn't the reccomendation to plan a circuit with shallow bank angle turns, but starts far before that in the basic climbs/turns/descents lesson. If a student can't get the idea of how the ball works by the end of it, then they shouldn't be progressing past it, but often they do in a race to get to the circuit. It should be of little suprise then that they don't do coordinated turns when they get to the circuit, which I think should be the stressed point of the colonel's complaint.

In flight training there is a big push to get into doing those crash and dashes and a lot of students skills suffer because of it.

This is IMO the most important post on this thread. Not demanding demonstrated competence on fundamental flying skills prior to starting in the circuit is IMO the single most prevalent failing in flight training today. Spending a whole lesson just in Attitudes and Movements and then practicing straight and level, climbs descents and turns until the student can accurately fly the aircraft is incredibly boring and tedious for the instructor but it is IMHO the foundation of good instruction. If the concept of yaw is introduced in attitudes and movements and the importance of co-ordinated flight is emphasized and practiced in climbs descents and turns then the slip/skid thing will be a moot point in the circuit.

As for bank angles in the circuit well I am a bank angle Nazi. I want to see 30 degrees at each corner of the circuit. Not 25 or 37 or any other number of degrees of bank angle, 30 is the number, and that is set not by looking at the AI but by looking at the natural horizon out the window. Why ? For the same reason I want to see 65 kts on final not 61 or 73 knots. Accurate flying is necessary for good landings and good landings come from good circuits. Fixing a poorly flown circuit by excessive bank angles is not what I want to see. Instead I want to force the student to get good at anticipating the future flight path of the aircraft so that a smooth 30 degree coordinated turn will put the aircraft in the right place.

Finally the best way to show a presolo student why skids are bad is to simulate a circuit (at altitude) and set up the classic late overbanked too low too slow base to final turn with the airplane ruddered around for line up as back stick is being fed in.

Lest you think I am a kill joy I am teaching formation and aerobatics to a 120 PPL in the Nanchang Cj6. One challenge with this aircraft is the very low gear speed and the fact that it is very hard to slow to gear speed in the circuit without excessively low power settings. Therefore the "normal" landing in this aircraft involves a low cruise power gear up final approach to 200 feet AGL followed by a climbing turn onto a close in downwind with 60 to 90 degrees of bank. Done properly the gear goes down as the wings are rolled level followed immediately by flaps down at the perch and a descending turn is made onto short final with only a slight power reduction as the turn is commenced. But The this PPL would not be flying this profile if he had not already demonstrated to me that he can maintain coordinated flight automatically and without conscious thought.

[ahramin]

BPF, I can understand where the 65 kts comes from, but where does 30° of bank come from?