Are 'Single 180 Turn From Downwind to Final' and 'Stall-spin on Turnfrom Base to Final' mutually exclusive?

I may have mentioned this before, but the series of my articles and tests currently being printed in Soaring magazine will continue for a few more months. As a result of this discussion, I am submitting a rather lengthy article about landing procedures / technique. My guess is it will not be published until early next year.

If I send in two pages of my popular Glider Flight Training Manual each month, it will take 15 years to publish all the information it contains.

You might consider upgrading to this new version rather than waiting.

Tom Knauff

On Sunday, July 31, 2016 at 11:46:23 AM UTC-7, wrote:
I may have mentioned this before, but the series of my articles and tests currently being printed in Soaring magazine will continue for a few more months. As a result of this discussion, I am submitting a rather lengthy article about landing procedures / technique. My guess is it will not be published until early next year.

If I send in two pages of my popular Glider Flight Training Manual each month, it will take 15 years to publish all the information it contains.

You might consider upgrading to this new version rather than waiting.

Tom Knauff

I thought of four situations when this "military",or button hook, landing pattern MIGHT be appropriate:

1. Terrain/buildings forced a tight base leg, such as an airstrip in a canyon.
2. Remaining altitude is at an absolute minimum for landing.
3. Unusual local weather conditions, like microbursts, are occurring.
4. The pilot wanted to impress his/her girl/boyfriend (just JOKING!).

In all other situations a square pattern (or a modified square pattern) is far safer. Flying a button hook pattern puts the runway out of sight to the pilot, so it is hard to judge how far you have flown, making it much more likely that an overshoot or undershoot landing will occur.

An important aspect of the square pattern, in addition to the visibility part, is to assess the winds aloft by the amount of crab required. I have been flying lately in conditions of high cross winds (10-20 kt) and even higher gusts (20-30 kt). Having a stabilized base leg is essential to judge this (the AWOS is just to old to be relied upon). If I were to fly a button hook pattern I would have a ground speed of 110-130 kt, given the high density altitudes we are flying and an 80 kt IAS (100 kt TAS + 10-30 kt tail wind)! This translates to up to 220 ft/sec (a 180 deg turn takes 10-20 sec and complicates the design point on when to start the turn). If you hit unexpected sinking air during this turn you could be in a real pickle! You may not experience these conditions where you fly, but a lot of accidents occur when flatlanders venture into high density altitude airports.

I also like to have A LOT of altitude when entering the pattern (2,000 ft). It is easy to burn off that altitude in modern gliders and it gives me options if something unexpected happens (like a plane pulling out onto the runway unannounced). Altitude lost is like runway behind you - it doesn't do you any good.

Tom

In all other situations a square pattern (or a modified square pattern) is far safer. Flying a button hook pattern puts the runway out of sight to the pilot, so it is hard to judge how far you have flown, making it much more likely that an overshoot or undershoot landing will occur.
What??? I always fly a descending 180 to short final and I /_never_/
lose sight of the runway. What are you doing that puts you in that
position? It's trivial to keep the landing point in view over your
shoulder until you begin the turn, unless you're flying way too far out
before beginning your final.

An important aspect of the square pattern, in addition to the visibility part, is to assess the winds aloft by the amount of crab required.
It's easy to assess winds on downwind and continuously through the final
turn without losing sight of the touchdown point. Drift is recognized
with peripheral vision and quick glances down at the ground. Final and
opposite patterns are monitored from downwind throughout the final
turn. Angle of descent is easily controlled by keeping the angle to the
touchdown point constant.

I have been flying lately in conditions of high cross winds (10-20 kt) and even higher gusts (20-30 kt). Having a stabilized base leg is essential to judge this
As said above, it's easy to judge during the downwind and throughout the
turn.
(the AWOS is just to old to be relied upon).
Very true!
If I were to fly a button hook pattern I would have a ground speed of 110-130 kt, given the high density altitudes we are flying and an 80 kt IAS (100 kt TAS + 10-30 kt tail wind)!
Why would you have a higher ground speed in turning flight than in
straight flight?
This translates to up to 220 ft/sec (a 180 deg turn takes 10-20 sec and complicates the design point on when to start the turn). If you hit unexpected sinking air during this turn you could be in a real pickle!
No, you're close enough that reducing dive brake will compensate for any
sink. If you're in a location with known high sink on final, e.g.,
Salida, CO, you should make your turn at the proper height and distance
from the runway.
You may not experience these conditions where you fly, but a lot of accidents occur when flatlanders venture into high density altitude airports.

I also like to have A LOT of altitude when entering the pattern (2,000 ft).
There goes flying where other pilots expect to see you!
It is easy to burn off that altitude in modern gliders and it gives me options if something unexpected happens (like a plane pulling out onto the runway unannounced). Altitude lost is like runway behind you - it doesn't do you any good.

Tom
Fly what works for you and don't disparage techniques that are out of
your sphere of experience.
--
Dan, 5J

On Sunday, July 31, 2016 at 10:32:02 PM UTC-4, Dan Marotta wrote:

Fly what works for you and don't disparage techniques that are out
of your sphere of experience.

....pop quiz then.

You're #3 in the pattern behind a student in a 1-34 flying a standard glider pattern and a tow plane. Behind you is another student + CFI in an L-23. What kind of pattern are you going to fly, and why?

I think there's a right answer to this question.

best,
Evan

Well, not that my answer matters much as I'm only a six year glider pilot, but I do come from a USAF background.

All else being equal I fly a curved pattern all the way from downwind to final. Flying that pattern does not stop nor preclude cross checks. I do not stare at the land point all the way around. I check the opposite base along my entire downwind leg. I check again throughout my pattern, and I look for straight in traffic prior to passing the 100-110 degree point where it gets under my belly. I also do not stop cross checks into the cockpit to monitor airspeed, altitude and yaw string. That constant cross check and outside look out has been ingrained in me for years. Even on short final I look around, nod to the duty crew, whatever. I have yet to see anything dangerous in this technique. I was taught you fly a pattern to get you to final in the envelop/cone where you still have correction ability on final--i.e. about half speed brakes.

I also fly TLAR... My goal in the pattern, is to hit half brakes all the way around the turn, never changing anything to fly a perfect pattern, roll out, no changes until flare, then touchdown at my aim point. I never quite get there, but that perfection goal challenges and pleases me, and I get pretty close some times. I have been able to fly the same pattern with multiple aircraft in the pattern (almost all of whom fly wider than I do). If I can't time my pattern to follow someone ahead and/or with someone behind, and not conflict with either no matter how I fly, I've got no business flying. Heck, I've held on opposite (right) base to let four gliders land who were in the opposite pattern before I curved my way in behind them in the remaining space.

That said, I am more than capable of flying square patterns, and I actually hit 45 degree or higher bank angles in my turns when I do. I do this when winds are high as a matter of course--the long, lower bank angle, continuous turn allows the winds to affect me more, and I prefer the hard, shorter turns, and the wind corrections and min drag of the straight legs and fast turns to the longer gentler draggier effects of the continuous turn. Less wind drag, less wind effect with the straighter legs it seems to me (i.e. more efficient approach).

My thoughts: my pattern keeps me closer to the field in case of rapid deterioration of flight conditions or glider problems. I find it much easier to visualize the cone and my approach to it as I'm flying it all the way around the pattern. Since I do not have to time the final turn, I have more time to do lookout, cross checks, etc as my flight inputs are relatively minor corrections all the way around. if I need to get down faster, outside rudder works great (practiced it on purpose, but have never required it).

It does make other glider pilots, or instructors at strange field checkouts a little nervous when they fly with me however, as they feel tight and find the constant turn weird or different.... But they have always said I've handled it safely and easily and got on final with zero issues.

Squeak

Squeaky, you're so much more articulate than I am. Thank you for
telling it the way I tried to!

Dan

On 8/1/2016 8:12 AM, Squeaky wrote:
Well, not that my answer matters much as I'm only a six year glider
pilot, but I do come from a USAF background.

All else being equal I fly a curved pattern all the way from downwind to
final. Flying that pattern does not stop nor preclude cross checks. I
do not stare at the land point all the way around. I check the opposite
base along my entire downwind leg. I check again throughout my pattern,
and I look for straight in traffic prior to passing the 100-110 degree
point where it gets under my belly. I also do not stop cross checks
into the cockpit to monitor airspeed, altitude and yaw string. That
constant cross check and outside look out has been ingrained in me for
years. Even on short final I look around, nod to the duty crew,
whatever. I have yet to see anything dangerous in this technique. I
was taught you fly a pattern to get you to final in the envelop/cone
where you still have correction ability on final--i.e. about half speed
brakes.

I also fly TLAR... My goal in the pattern, is to hit half brakes all
the way around the turn, never changing anything to fly a perfect
pattern, roll out, no changes until flare, then touchdown at my aim
point. I never quite get there, but that perfection goal challenges and
pleases me, and I get pretty close some times. I have been able to fly
the same pattern with multiple aircraft in the pattern (almost all of
whom fly wider than I do). If I can't time my pattern to follow someone
ahead and/or with someone behind, and not conflict with either no matter
how I fly, I've got no business flying. Heck, I've held on opposite
(right) base to let four gliders land who were in the opposite pattern
before I curved my way in behind them in the remaining space.

That said, I am more than capable of flying square patterns, and I
actually hit 45 degree or higher bank angles in my turns when I do. I
do this when winds are high as a matter of course--the long, lower bank
angle, continuous turn allows the winds to affect me more, and I prefer
the hard, shorter turns, and the wind corrections and min drag of the
straight legs and fast turns to the longer gentler draggier effects of
the continuous turn. Less wind drag, less wind effect with the
straighter legs it seems to me (i.e. more efficient approach).

My thoughts: my pattern keeps me closer to the field in case of rapid
deterioration of flight conditions or glider problems. I find it much
easier to visualize the cone and my approach to it as I'm flying it all
the way around the pattern. Since I do not have to time the final turn,
I have more time to do lookout, cross checks, etc as my flight inputs
are relatively minor corrections all the way around. if I need to get
down faster, outside rudder works great (practiced it on purpose, but
have never required it).

It does make other glider pilots, or instructors at strange field
checkouts a little nervous when they fly with me however, as they feel
tight and find the constant turn weird or different.... But they have
always said I've handled it safely and easily and got on final with zero
issues.

Squeak





--
Dan, 5J

On Monday, August 1, 2016 at 6:59:04 AM UTC-5, Tango Eight wrote:

...pop quiz then.

You're #3 in the pattern behind a student in a 1-34 flying a standard glider pattern and a tow plane. Behind you is another student + CFI in an L-23. What kind of pattern are you going to fly, and why?

Situation number 2: You enter the pattern a bit low (so not enough to orbit) and a student in a L-23 enters the pattern behind and below you - what kind of pattern are you going to fly and why?

There are times when a big "bomber" pattern are necessary and safer; there are also times when you have to get on the ground as fast as possible. A competently trained pilot can adapt to whatever situation is encountered and fly accordingly.

kirk
66

On Monday, August 1, 2016 at 9:27:37 AM UTC-4, kirk.stant wrote:
On Monday, August 1, 2016 at 6:59:04 AM UTC-5, Tango Eight wrote:

...pop quiz then.

You're #3 in the pattern behind a student in a 1-34 flying a standard glider pattern and a tow plane. Behind you is another student + CFI in an L-23. What kind of pattern are you going to fly, and why?

Situation number 2: You enter the pattern a bit low (so not enough to orbit) and a student in a L-23 enters the pattern behind and below you - what kind of pattern are you going to fly and why?

There are times when a big "bomber" pattern are necessary and safer; there are also times when you have to get on the ground as fast as possible. A competently trained pilot can adapt to whatever situation is encountered and fly accordingly.

kirk
66


So: what type of traffic pattern allows the greatest degree of flexibility to meet the needs of a wide variety of situations (traffic, weather, etc.)?


Where I'm going with this: the guy who has made up his mind 5 (or 500) miles out what sort of pattern he is going to fly ("I always...") and sticks to that plan like glue is a pain in the ass (at best).


best,
Evan

On 8/1/2016 9:34 AM, Tango Eight wrote:
Snip...

There are times when a big "bomber" pattern are necessary and safer;
there are also times when you have to get on the ground as fast as
possible. A competently trained pilot can adapt to whatever situation is
encountered and fly accordingly.

kirk 66

Completely agree...

So: what type of traffic pattern allows the greatest degree of flexibility
to meet the needs of a wide variety of situations (traffic, weather,
etc.)?

Is this a trick question?

Where I'm going with this: the guy who has made up his mind 5 (or 500)
miles out what sort of pattern he is going to fly ("I always...") and
sticks to that plan like glue is a pain in the ass (at best).

best, Evan

Completely agree with the PITA bit...nor do I see any fundamental conflict
between the above two views. "Choose wisely," is a great aviation mantra.

FWIW, the only two times I've been "surprised" in the pattern at Boulder (CO,
described earlier in the thread) was from bozo (as in both were experienced
enough and "should have known better [than to do what they did])" glider
pilots, one a visitor, one a local, who entered the pattern (very) late (and
low) from non-standard directions for prevailing conditions, necessitating I
alter my pattern plans, for separation and safety. "Properly educating" locals
is relatively straightforward; the visitor never reappeared & I have no idea
if he learned anything useful from his self-inflicted "idiot's pattern." It
easily could have had something of a bad snowball effect, depending on the
skills and experience of the others in the pattern just then (and there were 2
more in addition to me, as I recall).

Why anyone would thoughtfully choose to fly those sorts of patterns under
busy, benign-weather, conditions is beyond my way of thinking...

Bob W.

Hi Evan,

Of course you think there's a right answer because you're a proponent of
the square pattern which, if you've read my posts, I'm not at all
against. I just prefer to fly the pattern which works best _for me_ and
to date, nobody has complained about.

That said, I start monitoring the local field from about 20 miles out
and am aware of the traffic situation so I plan ahead and don't get into
the situation of being #3 but should it still happen:

1. I can reduce my speed considerably and pull up to give time to others.
2. Take a thermal and climb
3. Land on the parallel taxiway
4. Land on the cross wind runway
5. Land opposite direction (we have a long runway)
6. Land way long
7. Make a close in pattern in front of the 1-34 who's probably at twice
my distance from the runway. I'll be clear at the taxiway likely before
he turns final.

I'm sure I can think of more ways to mitigate the situation but I don't
feel constrained to drive an aircraft as though it were a train stuck on
the tracks. That's the main problem I see with "by the book" flying.
I'm not an outlaw and don't mean to come across that way, but I have to
sniff when I'm told that there's only one right way to do something.
One of my EE professors back in the early 70s (an old German) used to
sniff at what he called "cooking book engineers". I took that to heart
and try to do what I think is best for a given situation and what works
best for me. I understand that, as a CFI you're pretty much constrained
to teach by the book, but let me ask you this: Is there anything in the
FAA's Glider Flying Handbook that you know to be wrong? Do you teach it
wrong if it's so published or do you teach it right? I do what needs to
be done and yes, I could fly a square pattern in the situation you
described.

And another question: Have you ever seen someone really get into
trouble because the pilot in front of him in the pattern flew way too
far out before turning base and #2 felt that he had to fly even further
to maintain spacing? I have.

Now please tell me your correct answer. I'm genuinely interested and
I've enjoyed this discussion and hope that others less experienced might
undertake to learn to think outside the box.

Regards,
Dan

On 8/1/2016 5:59 AM, Tango Eight wrote:
On Sunday, July 31, 2016 at 10:32:02 PM UTC-4, Dan Marotta wrote:

Fly what works for you and don't disparage techniques that are out
of your sphere of experience.
...pop quiz then.

You're #3 in the pattern behind a student in a 1-34 flying a standard glider pattern and a tow plane. Behind you is another student + CFI in an L-23. What kind of pattern are you going to fly, and why?

I think there's a right answer to this question.

best,
Evan


--
Dan, 5J