FAA PTS "Slips to Landing" requirement vs No-spoiler landings

The past few weekends I've been watching some our our club students
being instructed on and practicing slips to a landing (i.e."no spoiler
landings") in preparation for their Private check rides. Gliders used
were our 2-33 and Blanik. I've also seen no-spoiler landings being
demonstrated in our G-103 - some quite nicely judged, I might add!

But I've been wondering about the utility and safety of this practice,
and whether it's taught in other countries - and if so, how it's
taught.

I realize that a no-spoiler approach is always an eventuality, and our
club even had one several years ago in a G-102 that left the glider in
the cornfield off the far end of the field, but it seems to me that
the skill learned in a slipped approach in a 2-33 may not really
transfer to a Discus 2 or other slippery glass ship, and that
conversely, realistic training - slipping all the way to touchdown, no
spoilers allowed - in a glass 2-seater (unless one has the luxury of a
really big field) could be somewhat hazardous.

It kind of reminds me of the old multi-engine requirement to
demonstrate Vmc at low altitudes, which was finally changed when the
authorities realized that they were killing more pilots in training
than in actual engine failures!

On the other hand, I've tried them in glass, including my Ls6 (which
does not recommend slips to a landing), and concluded that they are a
serious emergency that needs to be carefully thought out ahead of
time, and can only be safely practiced by breaking down into two
segments: First, no spoilers, slip to aim for the middle of the
field, then recover and land normally with spoilers as required; and
second, position the glider so as to be approaching the threshold at a
safe speed and altitude, then close spoilers, establish a slip, and
continue with the no-spoiler landing.

Comments? I'm especially interested in hearing how this is handled in
other countries.

Kirk
66

On Sep 10, 3:07*pm, "kirk.stant" wrote:

Comments? *I'm especially interested in hearing how this is handled in
other countries.

Kirk
66

I remember teaching brakes jammed open and brakes jammed closed in my
brief period of instructing in UK. That was a while ago so don't
know what is required now.

I practice full rudder slips in every glider I fly but usually in
combination with full airbrake. It's amazing how much faster even a
modern glass bird will come down if a full slip is added to full
brakes. I have more than once been very glad I knew how to do it, and
in particular how the airspeed indicator would behave.

Andy

Both scenarios were part of my training in South Africa. I have never
personally come across a situation where spoilers failed to open,
although I can certainly think of a number of scenarios where this
could happen. I do know of one where the spoiler handle on a Grob 103
broke after they had been deployed and jammed full open, resulting in
an off-field landing.

I was always taught to deploy spoilers close enough to the field that
you could make it if they jammed open and to make a longer circuit
with a moderate slip to landing if they jammed closed.

The Discus 2 slips very nicely - perhaps the double dihedral helps?

Mike

On Sep 10, 5:24*pm, Mike the Strike wrote:
Both scenarios were part of my training in South Africa. *I have never
personally come across a situation where spoilers failed to open,
although I can certainly think of a number of scenarios where this
could happen. *I do know of one where the spoiler handle on a Grob 103
broke after they had been deployed and jammed full open, resulting in
an off-field landing.

I was always taught to deploy spoilers close enough to the field that
you could make it if they jammed open and to make a longer circuit
with a moderate slip to landing if they jammed closed.

The Discus 2 slips very nicely - perhaps the double dihedral helps?

Mike

Several years ago I was checking out a visiting pilot in the Boulder
wave flying a G103 Twin III. The sky was overcast with heavy cirrus
and there were lenticulars and roll clouds. There was a lot of
moisture in the air and 4" snow on the ground. Surface temperatures
were around -4C.

He was doing great so I was just idly looking out the side when I
noticed the rectangle of the spoiler box as it faded away to smooth
white perfectly matching the rest of the wing. Quickly looking around
I saw that in addition to the ice filigree of frozen breath on the
inside of the canopy, there was ice forming on the outside too. Water
vapor in the air was freezing directly on the glider without passing
through a liquid state. We were icing up fast!

Calling this to the attention of the pilot, I asked for his judgment
as to how to deal with clear air icing. Get down! he shouted. Good
thought!

But when we pulled on the spoiler handle, it wouldn't move. They were
literally frozen shut. OK, I thought, now it gets interesting. Gusty
west wind day, a slick, snow covered runway and no spoilers - plus a
thinly frozen over lake at the far end.

Fortunately, as is often the case along the Rocky Mountain foothills
in Winter, there was a warm layer of +3C air between 2000 and 500 feet
AGL. That was enough to thaw the spoilers. I wasn't looking forward
to that landing without spoilers.

Once we stopped rolling in the -4C surface temperature, the spoilers
refroze - this time open. The visiting pilot got a better wave
checkout than either of us intended.

bildan wrote:
I wasn't looking forward
to that landing without spoilers.

Once we stopped rolling in the -4C surface temperature, the spoilers
refroze - this time open. The visiting pilot got a better wave
checkout than either of us intended.

It occurs to me that spoilers frozen shut provide two problems for a lot
of gliders: 1) getting the glider down safely on the ground by slipping,
and 2) stopping the glider on the ground without the wheel brake.

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly

* "Transponders in Sailplanes" http://tinyurl.com/y739x4
* Sections on Mode S, TPAS, ADS-B, Flarm, more

* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org

"Mike the Strike" wrote in message
...
I do know of one where the spoiler handle on a Grob 103
broke after they had been deployed and jammed full open, resulting in
an off-field landing.

And I know of a case where just one spoiler deployed on a glider. Causes a
nasty uncommanded roll. The only solution (once you figure out what is
going on) is to close the spoilers and proceed without them.

Vaughn

On Sep 10, 8:02*pm, "vaughn"
wrote:
"Mike the Strike" wrote in ... I do know of one where the spoiler handle on a Grob 103
broke after they had been deployed and jammed full open, resulting in
an off-field landing.

And I know of a case where just one spoiler deployed on a glider. *Causes a
nasty uncommanded roll. *The only solution (once you figure out what is
going on) is to close the spoilers and proceed without them.

Vaughn

Nah, you can do a really cool slip with one spoiler.

On Sep 10, 7:31*pm, Eric Greenwell wrote:
bildan wrote:

* *I wasn't looking forward

to that landing without spoilers.

Once we stopped rolling in the -4C surface temperature, the spoilers
refroze - this time open. *The visiting pilot got a better wave
checkout than either of us intended.

It occurs to me that spoilers frozen shut provide two problems for a lot
of gliders: 1) getting the glider down safely on the ground by slipping,
and 2) stopping the glider on the ground without the wheel brake.

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly

* "Transponders in Sailplanes"http://tinyurl.com/y739x4
* * * Sections on Mode S, TPAS, ADS-B, Flarm, more

* "A Guide to Self-launching Sailplane Operation" atwww.motorglider.org

No kidding!

I had flown IFR in the area for many years and knew to be on the
lookout for a low altitude warm layer. We just flew around at min
sink in the warm air until the ice melted, then entered the landing
pattern.

Someone with less experience might have missed that and rushed to a
spoilerless landing. Good thing Grobs have OAT gauges.

vaughn wrote:
"Mike the Strike" wrote in message
...
I do know of one where the spoiler handle on a Grob 103
broke after they had been deployed and jammed full open, resulting in
an off-field landing.

And I know of a case where just one spoiler deployed on a glider. Causes a
nasty uncommanded roll. The only solution (once you figure out what is
going on) is to close the spoilers and proceed without them.

Vaughn





Single spoiler deployment has caused at least one fatal accident.

If a linkage fails resulting in asymmetric airbrake deployment it is
possible to run out of options very quickly.

My thoughts are that you need to open the brakes to balance the drag and
lift asymmetry. Then you can fly the aircraft through the resulting
descending roll and recover. Depending on your height and speed it may
be quite pressing to land, it may also be quite pressing to reduce speed...
However - if this happens in a high energy state (where else?) you may
already have a lot of yaw and roll inertia by the time you get the other
airbrake open. Especially on a long winged open class ship there may
just not be enough control authority left, and if you are very fast
and/or very close to the ground the options are limited.

To overcome the differential lift caused by the yaw you may need full
rudder.
To limit the speed and avoid terrain you may need large elevator deflection.
To reverse the roll and return to level flight you almost certainly will
need full aileron.

You are unlikely to find such a high G, rolling pull up close to , or
over Vne with airbrakes deployed in the manual.

There is a reason for that "max manoeuvre speed" entry...

A little math says that at 250km/h and 300m (~1000")AGL a 30 degree
descent angle will give you less than 8 seconds to avoid terrain.

I once had one spoiler fully out due to a failure of a diecast aluminium
bracket in a Grob Astir. This broke in flight, with a loud bang as the
left airbrake suddenly sucked open and stayed there. I then found that I
needed almost full right aileron and rudder to conteract the roll and yaw
to the left. I was only about 900ft AGL at the time.

The solution I worked out was to open the the other airbrake, which still
worked, and then make the best more or less straight ahead landing that I
could into a field. I had to sideslip the glider to get in, but walked
away from it and didn't further damage the glider.

BTW, this and another case is why many Grob Astirs have a little perspex
inspection window under the wing, so that you can see the offending
bracket.

Getting back to the original subject, we do teach no airbrake approaches
in the UK as a post solo exercise, just in case the airbrake mechanism
fails, or the brakes freeze shut while wave soaring. I have made a video
of such an exercise, but you float an awfully long way in ground effect,
which is why I eventually told the student to open the brakes, as it was
the last flight of the day and we wanted to stop somewhere near to the
hangar. See:

http://www.youtube.com/watch?v=5t7xnls2w5k

This was done in a K13, which sideslips very nicely and very much more
effectively than most glass gliders. With a lot of slip on, the ASI will
usually totally misread.

Derek Copeland

P.S. I know the Yanks call a sideslip a 'forward slip' before someone
pulls me up on that!


At 02:02 11 September 2009, vaughn wrote:

"Mike the Strike" wrote in message
...
I do know of one where the spoiler handle on a Grob 103
broke after they had been deployed and jammed full open, resulting in
an off-field landing.

And I know of a case where just one spoiler deployed on a glider.
Causes
a
nasty uncommanded roll. The only solution (once you figure out what is
going on) is to close the spoilers and proceed without them.

Vaughn