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

The 'Single 180 Turn From Downwind to Final' (aka 'military style pattern') and 'Stall-spin on Turn from Base to Final' are both well discussed as independent topics on RAS. But I've not seen anything about how these pieces fit together.

Having recently tried the 'Single 180 Turn...' and LIKED it, I'm wondering if there is any good reason why I should not fly this approach at an uncontrolled airport with mostly glider traffic. What about at a controlled airport with mostly GA power traffic?

And I'm wondering if anyone has ever stall-spinned from a 'Single 180 Turn....' pattern and whether there are subtle 'gotchas' associated with that pattern shape that I should know about.

What is the military's track record wrt 'Stall-spin in the pattern'? Does it happen just as often with the 'Single 180 Turn...'?

You need to try the inverted flight landing pattern. It gives a great view of the earth, making it easier to make some decisions.

Yep, there is a "best way" after you take everything into consideration.

Tom

If you are talking about glider flying for the military, I don't believe West point has a club, Navy flies at a local SSA club, and the Air Force Academy Flies a standard right-hand pattern that is tower controlled and in Class D Airspace.

The Air Force's record prior to making it an enforced and strict program was not all that terrific, but since regimenting the program and beating airspeed control into student's heads, they may have one of the best safety records in the gliding world (incident per flights)...

Probably goes to show that you can fly whatever pattern you want as long ask you maintain a safe airspeed for your flight condition.

I don't normally weigh in on things like this because of the (many) passionate opinions about "proper" this or that, but last year when I was getting a check ride with a Designated FAA Examiner in the jet powered TsT-14 BonusJet glider(www.desertaerospace.com), I was chastised for doing a tight 180 to final. "Your head and eyes are focused on the threshold and touchdown point from downwind to final. This is an uncontrolled airport. If you had a guy without a radio on final, you will never see him. Do a square pattern with crisp a 90 degree turn from downwind to base, look over to the opposite direction to clear for traffic and make a crisp 90 to final."

Two flights later, that scenario happened while I was approaching to land in my Pegasus 101A. Looked right on my left downwind to base and saw a rather disturbing sight. I elected to take the adjacent taxiway to avoid being run over by a KingAir who had made a long straight-in final approach, happily announcing his intentions over the radio....but not on the airport frequency.

I mentioned it to him as he was getting gas. At first he growled about almost getting "cut off" in the pattern by some dumbass glider pilot, but his face went white when I asked him what frequency he was using. Turns out he was still on ABQ Center and not 122.90, the Moriarty frequency. Live and learn. I appreciate good advice, and my normal pattern for landing has some margin built in after that little incident.

I'm in the 180 descending turn to final camp and, flying downwind much
closer than the "squares" I spend half my time watching my touchdown
point and the final approach path for unannounced traffic on long final
approaches. It's no big effort to look out on final during the turn
while monitoring my intended touchdown point.

Having said the above, I think any pilot will make better patterns if he
flies them as he was taught and has practiced. Of course, you can learn
and practice the other method but you won't be quite as good at it until
your experience at it improves. Have fun and fly safe!

On 7/27/2016 7:52 PM, wrote:
I don't normally weigh in on things like this because of the (many) passionate opinions about "proper" this or that, but last year when I was getting a check ride with a Designated FAA Examiner in the jet powered TsT-14 BonusJet glider(www.desertaerospace.com), I was chastised for doing a tight 180 to final. "Your head and eyes are focused on the threshold and touchdown point from downwind to final. This is an uncontrolled airport. If you had a guy without a radio on final, you will never see him. Do a square pattern with crisp a 90 degree turn from downwind to base, look over to the opposite direction to clear for traffic and make a crisp 90 to final."

Two flights later, that scenario happened while I was approaching to land in my Pegasus 101A. Looked right on my left downwind to base and saw a rather disturbing sight. I elected to take the adjacent taxiway to avoid being run over by a KingAir who had made a long straight-in final approach, happily announcing his intentions over the radio....but not on the airport frequency.

I mentioned it to him as he was getting gas. At first he growled about almost getting "cut off" in the pattern by some dumbass glider pilot, but his face went white when I asked him what frequency he was using. Turns out he was still on ABQ Center and not 122.90, the Moriarty frequency. Live and learn. I appreciate good advice, and my normal pattern for landing has some margin built in after that little incident.

--
Dan, 5J

On 7/27/2016 5:33 PM, son_of_flubber wrote:
The 'Single 180 Turn From Downwind to Final' (aka 'military style pattern')
and 'Stall-spin on Turn from Base to Final' are both well discussed as
independent topics on RAS. But I've not seen anything about how these
pieces fit together.

So how many glider pilots are in the room and how many opinions will they have
regarding your implicit question?! (Chortle.) As always, the devil is in the
details, and in my (experience-based) view there's no single "absolutely
right" answer. There are many very good reasons we're instructed to "fly
regulation glider patterns," but the accident record clearly shows that
attempting to do so is far from a panacea. If it's possible and it helps you,
then fine - do it. You'll likely have full approbation of the glider
community, instructors included. But never lose sight of what a landing
pattern is intended to do: help you make a safe landing, at the spot you've
selected.

Some years ago I flew an original-spanned HP-14 with the as-designed (see next
paragraph) ailerons from a busy, non-towered GA airport with 3 parallel
runways (Boulder, CO). Back then, the paved/lit one was "the power runway"
(legally available for glider use, of course). (An estimated) 100 feet
center-line-to-center-line to the north were two, unpaved "glider only"
runways. The northernmost one was the one from which 99.9% of all gliders
launched (trailers/tiedowns/assembly-area being immediately north of it), and
maybe 70% of the gliders and 50% of the towplanes landed. The center one
(rarely) launched and (variously) landed the remainder. Occasionally
non-towing taildraggers would use one or the other of "the glider runways."
The glider runways' landing percentages varied with traffic volume, landing on
the northernmost runway being the default, traffic permitting. When the sky
occasionally rained gliders, gliders would sometimes "land long," overflying
ships landed short, though this wasn't common. Point being, it was/is a *busy*
airport, and pilots were/are taught/expected to keep their heads on a swivel.
Shoot, we practiced their "situational awareness" long before it became a
catchphrase, as a means of NOT having to do anything "unusual" in the landing
pattern! (Google Earthing will show the northernmost runway is now paved. Last
time I looked, there was a glider in the pattern!)

A common mod to original-aileroned HP-14s was to convert the outer 3-feet of
each flap to ailerons, since as-designed, no one would characterize its roll
rate as "spritely." Evidently the increased roll rate was deemed more
worthwhile than the reduced (but still manly) flap-power....but I wouldn't know.

Boulder's published/recommended pattern procedure, is for gliders to fly a
rectangular pattern, crosswind entered at midfield, downwind/base/final inside
the power equivalents, left-hand to the east, right-hand to the west. It's not
uncommon to have a power plane or two buzzing along downwind for company,
though parallel takeoffs are "seriously discouraged"/prohibited and parallel
landings likewise discouraged. At some point in every landing pattern, of
course, the glider's spacing/timing options vanish, though some might find it
surprising how much flexibility gliders bring to the table, assuming good
"situational awareness."

The preceding verbosity can be shortened to: gliders must fly their patterns
inside the power plane pattern. It generally works well.

So - I'm landing a slow-rolling glider with relatively high stick forces in
roll (and light elevator forces), using a pattern distinctly constrained in
size. While it was possible to make 90-degree-turn-patterns in the HP-14 at
Boulder, it pretty much took both hands on the stick to do it and was
something of a distraction/PITB judging when to begin the turn to final. It
was considerably easier, both in stick forces and in
mentally/visually/continuously assessing the approach, to make the transition
from downwind to final a continuously/varying-as-necessary-banked turn. I felt
it was equally as safe as "a standard glider pattern" too, in
traffic-avoidance turns...I could still easily check the power final, for
example, and one can rationalize that banked gliders are easier to spot than
unbanked ones.
- - - - - -

Having recently tried the 'Single 180 Turn...' and LIKED it, I'm wondering
if there is any good reason why I should not fly this approach at an
uncontrolled airport with mostly glider traffic. What about at a
controlled airport with mostly GA power traffic?

There's a lot to be said favoring "When in Rome, do as the Romans," but YMMV.
I've no doubt others will share other (and I'll wager, strongly held!) views
on these questions.
- - - - - -

And I'm wondering if anyone has ever stall-spinned from a 'Single 180
Turn...' pattern and whether there are subtle 'gotchas' associated with
that pattern shape that I should know about.

Having immense faith in human ability to screw up, I'll put real money on
people "departing from controlled flight" in *every* landing pattern known to
mankind! Personally, I think the circling-pattern gotchas not fundamentally
different from *any* pattern's "Gotchas!" Airspeed and coordination rule.
Presupposing those are as-desired, don't hit anything other than the spot for
which you're aiming. As for judging how you're doing relative to bad things to
hit in the landing pattern while in controlled flight, there's considerable
experience favoring certain pattern shapes...and less for others (due both to
less use, and as well to "It's just a bad idea!" for some [e.g.
straight-ins]). In my motherhood and apple-pie view, a pattern is no more and
no less than an unavoidable-vehicle/useful-aid to making safe landings.

I never discerned substantive differences/difficulties between using
rectangular patterns and circling patterns, but YMMV.

When I sold the HP and began flying a Zuni, I transitioned back to rectangular
patterns, following the "When in Rome..." philosophy. The (sole) off-field
landing I made in the HP I used a rectangular pattern, just because the chosen
field was huge, with a no-brainer approach, and I could.
- - - - - -

What is the military's track record wrt 'Stall-spin in the pattern'? Does
it happen just as often with the 'Single 180 Turn...'?

Good luck obtaining hard data on this front! I've read (can't recall where)
the Navy's approach-to-carrier-landings accidents (metric unknown) dropped by
a factor of 3 when they post-WW-II adopted the circling approach in
conjunction with "flying AOA" (early 1950s?). I'd love to see that data.

Bob W.

On Thursday, 28 July 2016 00:33:48 UTC+1, son_of_flubber wrote:
The 'Single 180 Turn From Downwind to Final' (aka 'military style pattern') and 'Stall-spin on Turn from Base to Final' are both well discussed as independent topics on RAS. But I've not seen anything about how these pieces fit together.

Having recently tried the 'Single 180 Turn...' and LIKED it, I'm wondering if there is any good reason why I should not fly this approach at an uncontrolled airport with mostly glider traffic. What about at a controlled airport with mostly GA power traffic?

And I'm wondering if anyone has ever stall-spinned from a 'Single 180 Turn...' pattern and whether there are subtle 'gotchas' associated with that pattern shape that I should know about.

What is the military's track record wrt 'Stall-spin in the pattern'? Does it happen just as often with the 'Single 180 Turn...'?

It sounds as though what we teach in the UK may be a little different to the USA approach (sorry for the pun).

We divide the downwind to base turn into two approximately 45 degrees turns, to insert a 'diagonal leg'. After passing low key, instead of continuing a long way downwind to make a rectangular circuit, we turn 45 degrees onto a diagonal, and later make another 45 degree turn onto a shorter base. Advantages over the rectangular circuit are keeping the landing area in site, and maintaining something closer to a constant glide angle to the reference point, which makes it easier to judge whether too high, too low or about right. It is a matter of judgement how soon or how far after passing low key to turn onto the diagonal.

On Thursday, July 28, 2016 at 5:36:38 PM UTC-4, waremark wrote:

We divide the downwind to base turn into two approximately 45 degrees turns, to insert a 'diagonal leg'. After passing low key, instead of continuing a long way downwind to make a rectangular circuit, we turn 45 degrees onto a diagonal, and later make another 45 degree turn onto a shorter base.

And then you make a 90 degree turn from base to final?

At 00:26 29 July 2016, son_of_flubber wrote:
On Thursday, July 28, 2016 at 5:36:38 PM UTC-4, waremark wrote:

We divide the downwind to base turn into two approximately 45 degrees
tur=
ns, to insert a 'diagonal leg'. After passing low key, instead of
continuin=
g a long way downwind to make a rectangular circuit, we turn 45 degrees
ont=
o a diagonal, and later make another 45 degree turn onto a shorter
base.=20

And then you make a 90 degree turn from base to final?


Yup

The majority of gliders are more stall and spin resistant at medium to steeper banks than at shallower bank angles. (This is aerodynamically different than most airplanes). A continuous 30 degree bank from downwind to final exposes a pilot to a longer period of stall/spin-at-low-altitude risk than two brief periods of stall/spin resistant steeper banked turns. (Or 3 turns in the clipped base pattern).

Turning flight presents a more dynamic visual picture then straight flight. Most normally equipped humans are better at assessing and reacting to the changing energy state of the glider (relative to landing area & speed) as well as detecting conflicting traffic and other hazards during wings level straight flight than during turning flight. This may be due to the less dynamic visual presentation in straight flight. This is especially true while under stress.

While it is true that many of you normally performing well trained pilots can safely fly all kinds of approaches, common sense suggests training and establishing flying habits that are more likely to result in safe outcomes when normal conditions and normal performance deteriorates.

The fact that we are still debating these things in 2016 makes me want to beat my head against the canopy.