Stall/spin and ground reference maneuvers

I agree, there are multiple inputs to the pilot. The trick is prioritizing them and not getting distracted. I'm probably not any better at it than you; it's more likely that my instructors taught me somewhat differently.

On downwind I concentrate on airspeed, variometer rate, and traffic scan (I'll note the position of the runway as part of my traffic scan). When the runway disappears I'll wait an appropriate amount of time (judged from how fast I moved down the runway), take a quick look for traffic, runway position and turn roll out reference, and then (and only then) initiate my turn to base. During the 5 seconds I'm turning I'm looking directly forward over the nose, paying attention only to airspeed, yaw string and bank angle. The bank angle I always try to use is 45 degrees, while auxiliary inputs are slipstream noise, one or two glances at the ASI, the appearance of the rollout reference, and the imagined voice of my instructor chanting "airspeed, yaw string" over and over.

On the base leg I again concentrate on airspeed, variometer rate, and traffic scan (again noting the runway position as part of my traffic scan). At the appropriate position (judged from how fast the runway extended centerline is approaching, I initiate my turn to final. During the 5 seconds I'm turning I'm again looking directly forward over the nose, paying attention only to airspeed, yaw string and bank angle. Again the bank angle I always try to use is 45 degrees, while auxiliary inputs are slipstream noise, one or two glances at the ASI, the appearance of the runway, and the imagined voice of my instructor chanting "airspeed, yaw string" over and over.

Until a few months ago when I read about "pivot height" on this board, I had never known that the wing tip direction could reverse direction during a turn depending on your height. I assure you that's not from lack of experience on my part, it's just that I never look at the ground when I'm low and turning.

I also agree with you that the numbers of stall/spin accidents are appalling. As a community we need to try to reduce them. I just don't know if making people aware of peripheral vision changes is the way forward. Isn't it better to get them to focus only on what matters for the few seconds that are needed in a low altitude turn?

-John, Q3

On Tuesday, March 4, 2014 9:54:01 AM UTC-5, wrote:
On Tuesday, March 4, 2014 5:34:09 AM UTC-8, John Carlyle wrote:

Just because you perceive something doesn't mean that you have to pay attention to it. The most important things in a pattern turn (or low altitude thermalling) are perfectly coordinated turns and proper airspeed. Scans for traffic and feeling for lift are fine, but who cares what the ground does?



One does look at the airport when initiating the turn from base to final, but once the turn starts all you need to do for the next 5 seconds is look over the nose for pitch, yaw and bank. The airport will appear when you need it without having to search for it.



Well, it's a human in the loop feedback control system with multiple inputs - visual, inertial and some auditory. If you are making a low turn from base to final you may initiate the turn while looking away from the yaw string and airspeed because the runway is off to the side and you are trying to set a turn rate to put you in-line with the runway on final. At the same time your peripheral vision at this altitude is now subtly telling you that you are over-banked/under-ruddered because you are below the pivotal height where the turning cues of the wing against the background reverse. You aren't used to this peripheral cue and may not be aware of how it affects your overall perception of attitude and coordination and how that feeds back into the control system.

You may be better at it than I am, but I can't just take a snapshot to the side before initiating the turn to final and then look ahead to the yaw string and airspeed without ever looking out to the runway again and expect to end up both pointed at and in-line with the runway heading. I tend to scan back and forth. It only takes a moment of being over-ruddered to generate a spin, particularly if you are at low speed (and an approach into an airport in a mountain valley can make you fly too nose-high if you are not paying proper attention).

Is any of this good and proper airmanship - well no. But that is a little beside the point. The fact is that over the past 20 years 39% of fatal glider accidents and 36% of all glider fatalities have been due to stall/spin. That's 43 dead glider pilots and passengers, or slightly more than two per year. It is the leading cause of death while flying gliders. We must be doing something (or some things) wrong. My thought is if we are all aware that our perception from peripheral vision changes (and which way those changes work) we all may be in a slightly better position to resist the subconscious urge to do the wrong thing at just the wrong time.

9B

I wonder if part of the problem we have in patterns is the patterns themselves. Probably because of a military aviation background, I really (for both power and gliders) prefer the military continuous 180 turn from a lower closer downwind to final to the civilian higher, downwind - turn - base - turn - final approach.

I keep the pattern speed a bit high (say 60 - 65 knots in glass), half spoilers abeam the touchdown aimpoint, about 500' agl, pretty close in to the field, then at the TLAR point, roll into about 30 degrees of bank and turn in. If wide I can steepen up, if tight open out, but the turn is one continuous turn until rollout on final, and then I start transitioning to my final speed and adjusting to where I want to touch down.

Lower and closer in, I find it a lot easier to judge the angles; I HATE long finals!

So the turn is pretty much like any thermalling turn while adjusting the center, without having to roll completely in and out twice with the usual chance to under/over rudder the turn..

Just my 2 cents...

Kirk
66

On 3/4/2014 9:54 AM, kirk.stant wrote:
I wonder if part of the problem we have in patterns is the patterns
themselves. Probably because of a military aviation background, I really
(for both power and gliders) prefer the military continuous 180 turn from a
lower closer downwind to final to the civilian higher, downwind - turn -
base - turn - final approach.

I keep the pattern speed a bit high (say 60 - 65 knots in glass), half
spoilers abeam the touchdown aimpoint, about 500' agl, pretty close in to
the field, then at the TLAR point, roll into about 30 degrees of bank and
turn in. If wide I can steepen up, if tight open out, but the turn is one
continuous turn until rollout on final, and then I start transitioning to
my final speed and adjusting to where I want to touch down.

Lower and closer in, I find it a lot easier to judge the angles; I HATE
long finals!

So the turn is pretty much like any thermalling turn while adjusting the
center, without having to roll completely in and out twice with the usual
chance to under/over rudder the turn..

Just my 2 cents...

Kirk 66

FWIW...

Way back when I had about 200 total hours, all glider, I flew an HP-14 from a
busy municipal airport with 3 closely-spaced parallel runways. SOP traffic
separation had gliders flying a 4-sided pattern entered from midfield, the
downwind, base and final legs being inside the same-turning-direction power
pattern, which normally used the southernmost E-W runway.

Schreder's original HP-14 design wasn't noted for being a rapid roller. While
it WAS possible to fly a rectangular pattern in it inside the power pattern,
doing so required serious (both arms essentially required) stick effort to
achieve max aileron deflection on the final-to-base and base-to-final turns,
to the point I found doing so a mental distraction...and thus less than
"ideally safe."

I found "a circling approach" (a la the U.S. Navy) from downwind to final
considerably easier - and a no-brainer, as Kirk suggests above - to implement.
A circling approach quickly became my standard procedure in that ship at that
airport.

When people asked, I told 'em why. Few asked.

Bob W.

I know someone who flies the pattern as you describe; he had flown F-4's onto carriers. My instructor told me he felt it was safer to separate tasks in the pattern rather than combine them. So I do it his way...

-John, Q3

On Tuesday, March 4, 2014 11:54:37 AM UTC-5, kirk.stant wrote:
I wonder if part of the problem we have in patterns is the patterns themselves. Probably because of a military aviation background, I really (for both power and gliders) prefer the military continuous 180 turn from a lower closer downwind to final to the civilian higher, downwind - turn - base - turn - final approach.

I keep the pattern speed a bit high (say 60 - 65 knots in glass), half spoilers abeam the touchdown aimpoint, about 500' agl, pretty close in to the field, then at the TLAR point, roll into about 30 degrees of bank and turn in. If wide I can steepen up, if tight open out, but the turn is one continuous turn until rollout on final, and then I start transitioning to my final speed and adjusting to where I want to touch down.

Lower and closer in, I find it a lot easier to judge the angles; I HATE long finals!

So the turn is pretty much like any thermalling turn while adjusting the center, without having to roll completely in and out twice with the usual chance to under/over rudder the turn..

Just my 2 cents...

Kirk
66

I must be at risk! As I think and do it a bit differently to most here.

In the circuit I trim for landing speed c. 50% above stall speed + c. half
the headwind speed. In still air in my 27 this is 52kts and in a gale it
could be 70 or 80kts. Fast is good unless in something like a Duo going
into a small field!

In the UK we are taught not to fly a square circuit, we lop off the
downwind corner to keep us closer to the airfield (less downwind) and keep
the landing area and reference point in view. This tends to induce a
curving base leg anyway.

I aim to get at the final turn between 300ft and higher if windy and I put
in a steeply banked final turn. The steeper the bank the harder it is to
over rudder into a spin. Probably impossible at 45 or more - Chris Rollings
would know. It is also much harder to stall requiring a lot of elevator.

From the point of starting my final turn to landing I am pretty much
focussed only on the reference point and the airspeed. Keep the airspeed
pegged and use the brake to arrive in the right place.

This close to the ground it is pretty obvious if you are slipping, which
could of course be intentional. If you are side slipping on purpose you
probably don't have enough elevator to stall.

Should I give up before I kill myself?

I fly my pattern just like Kirk, though a little higher and faster at the
start. I begin my descending final turn when abeam the touchdown point and
roll out on final at about 200 ft and over the numbers. I do this both in
my LAK and in the tow planes.

I did it this way in the Air Force and when I flew a King Air for
FlightSafety. The only exception was in the B-727. Gotta be gentle for the
pax.

"kirk.stant" wrote in message
...
I wonder if part of the problem we have in patterns is the patterns
themselves. Probably because of a military aviation background, I really
(for both power and gliders) prefer the military continuous 180 turn from a
lower closer downwind to final to the civilian higher, downwind - turn -
base - turn - final approach.

I keep the pattern speed a bit high (say 60 - 65 knots in glass), half
spoilers abeam the touchdown aimpoint, about 500' agl, pretty close in to
the field, then at the TLAR point, roll into about 30 degrees of bank and
turn in. If wide I can steepen up, if tight open out, but the turn is one
continuous turn until rollout on final, and then I start transitioning to my
final speed and adjusting to where I want to touch down.

Lower and closer in, I find it a lot easier to judge the angles; I HATE long
finals!

So the turn is pretty much like any thermalling turn while adjusting the
center, without having to roll completely in and out twice with the usual
chance to under/over rudder the turn..

Just my 2 cents...

Kirk
66

Dan,

Would you do a circling approach if you were going into a difficult strip, too? Say, a narrow cornfield surrounded by trees. I ask because the Navy pilots I know who fly gliders have reverted to the non-circling approach.

-John, Q3

On Tuesday, March 4, 2014 12:59:10 PM UTC-5, Dan Marotta wrote:
I fly my pattern just like Kirk, though a little higher and faster at the
start. I begin my descending final turn when abeam the touchdown point and
roll out on final at about 200 ft and over the numbers. I do this both in
my LAK and in the tow planes.

I did it this way in the Air Force and when I flew a King Air for
FlightSafety. The only exception was in the B-727. Gotta be gentle for the
pax.

John,

Yes, I would. It's the pattern I've flown for 40+ years and it's always
worked well for me. I would not consider changing to a square base with a
90 degree turn to final during a critical outlanding at a fenced field.
Likewise, I wouldn't advise anyone to switch to a circling landing under the
same circumstances.

I plan my patterns to roll to a stop at the same location every time using
minimal wheel brake. I do this with calm winds and 30+ kt winds. I find it
easier to plan and execute simply by changing the point where I begin my
final turn.

PS - Navy pilots can't land, then only crash and hope the wire stops them
before they go over the side. ;-)

"John Carlyle" wrote in message
...
Dan,

Would you do a circling approach if you were going into a difficult strip,
too? Say, a narrow cornfield surrounded by trees. I ask because the Navy
pilots I know who fly gliders have reverted to the non-circling approach.

-John, Q3

On Tuesday, March 4, 2014 12:59:10 PM UTC-5, Dan Marotta wrote:
I fly my pattern just like Kirk, though a little higher and faster at the
start. I begin my descending final turn when abeam the touchdown point
and
roll out on final at about 200 ft and over the numbers. I do this both
in
my LAK and in the tow planes.

I did it this way in the Air Force and when I flew a King Air for
FlightSafety. The only exception was in the B-727. Gotta be gentle for
the
pax.

Thanks, Dan. I suspected you'd keep on with what was familiar to you.

-John, Q3

PS - My Navy buddies tell me they do circling approaches because the airstrip is moving. Air Force pilots copy Navy pilots because the field knows an Air Force pilot is coming and it will run away... grin

On Wednesday, March 5, 2014 11:10:00 AM UTC-5, Dan Marotta wrote:
John,

Yes, I would. It's the pattern I've flown for 40+ years and it's always
worked well for me. I would not consider changing to a square base with a
90 degree turn to final during a critical outlanding at a fenced field.
Likewise, I wouldn't advise anyone to switch to a circling landing under the
same circumstances.

I plan my patterns to roll to a stop at the same location every time using
minimal wheel brake. I do this with calm winds and 30+ kt winds. I find it
easier to plan and execute simply by changing the point where I begin my
final turn.

PS - Navy pilots can't land, then only crash and hope the wire stops them
before they go over the side. ;-)

"John Carlyle" wrote in message
...
Dan,

Would you do a circling approach if you were going into a difficult strip,
too? Say, a narrow cornfield surrounded by trees. I ask because the Navy
pilots I know who fly gliders have reverted to the non-circling approach.

-John, Q3


On Tuesday, March 4, 2014 12:59:10 PM UTC-5, Dan Marotta wrote:

I fly my pattern just like Kirk, though a little higher and faster at the

start. I begin my descending final turn when abeam the touchdown point

and

roll out on final at about 200 ft and over the numbers. I do this both

in

my LAK and in the tow planes.



I did it this way in the Air Force and when I flew a King Air for

FlightSafety. The only exception was in the B-727. Gotta be gentle for

the

pax.

snort, chuckle...


"John Carlyle" wrote in message
...
Thanks, Dan. I suspected you'd keep on with what was familiar to you.

-John, Q3

PS - My Navy buddies tell me they do circling approaches because the
airstrip is moving. Air Force pilots copy Navy pilots because the field
knows an Air Force pilot is coming and it will run away... grin

On Wednesday, March 5, 2014 11:10:00 AM UTC-5, Dan Marotta wrote:
John,

Yes, I would. It's the pattern I've flown for 40+ years and it's always
worked well for me. I would not consider changing to a square base with
a
90 degree turn to final during a critical outlanding at a fenced field.
Likewise, I wouldn't advise anyone to switch to a circling landing under
the
same circumstances.

I plan my patterns to roll to a stop at the same location every time
using
minimal wheel brake. I do this with calm winds and 30+ kt winds. I find
it
easier to plan and execute simply by changing the point where I begin my
final turn.

PS - Navy pilots can't land, then only crash and hope the wire stops them
before they go over the side. ;-)

"John Carlyle" wrote in message
...
Dan,

Would you do a circling approach if you were going into a difficult
strip,
too? Say, a narrow cornfield surrounded by trees. I ask because the
Navy
pilots I know who fly gliders have reverted to the non-circling
approach.

-John, Q3


On Tuesday, March 4, 2014 12:59:10 PM UTC-5, Dan Marotta wrote:

I fly my pattern just like Kirk, though a little higher and faster at
the

start. I begin my descending final turn when abeam the touchdown
point

and

roll out on final at about 200 ft and over the numbers. I do this
both

in

my LAK and in the tow planes.



I did it this way in the Air Force and when I flew a King Air for

FlightSafety. The only exception was in the B-727. Gotta be gentle
for

the

pax.