Double Release Failure

On Sep 7, 7:05*pm, ZZ wrote:
It is likely that the probability of an ACTUAL double release failure on
tow is what ever positive number is closest to zero. Of course that
doesn't mean that Mr.Murphy can't serve one of these up.

I would be interested in hearing any accounts of actual, non-instructor
induced double release failures which required either a landing on tow
or purposely breaking he rope to end the problem.

I would also be interested in any opinions regarding practicing landing
on tow to prepare oneself for this unlikely event. (I know that this is
or was a required maneuver in some European countries...but is it worth
the risk?)

Paul
ZZ

I had a release failure (mostly) on my Open Cirrus (CG hook) once. I
landed one thermal short of home plate at a neighboring glider club
(UK). I handed a cheque out the clear vision panel and took a
launch. When I got to altitude and distance, I pulled the release.
Nothing. I pulled another dozen times in rapid succession, nothing.
I called the tow plane on the radio, no answer. Called several more
time, nothing. I flew out to the left and waggled the wings, no
response from the tow plane. I was hoping he wasn't going to give me
the "bugger off" wing waggle and turn back. A few more pulls and it
let go thankfully. Next step would have been to put in the slack
and break it. Seemed a long time, but really only a few moments. The
TOST hook was replaced before the next flight. No broken springs,
just wear.

So, I guess it really depends on how you define release failure.

Frank Whiteley

Paul,
I was fortunate enough to be trained in this procedure, albeit 35+
years ago. I was at summer camp that Fred Robinson had for kids at
Crystalaire. We're jarring a few cobwebs here but if I remember
correctly, the glider would decend to a low tow position and use the
spoilers for decent. The glider would touch down first but you had to
be careful not to stall and drop the towplane in with excessive
braking.

We had a 1-34 at the time that needed a radio installed. We didn't
have a trailer and the nearby radio shop was at a tower controlled
airport (KAPC). We called the tower and they suggested that the
glider land with the towplane that had a radio. I wasn't old enough
to fly powerplanes yet so my father flew the towplane and I flew the
glider. The airport was quite large and the flight was uneventful.

Bottom line, it's not as scary as it sounds but I would suggest proper
training before trying this on your own. Is anyone teaching this
anymore?

Barry

*Is anyone teaching this
anymore?

Barry

Sure. It's a good exercise for proficiency and confidence building.
Touch and goes, taxiing and even turning at runway intersection to
take off on a different runway. Good communication, experienced tow
pilots, proper conditions, FUN!

On Sep 7, 11:21*pm, wrote:
**Is anyone teaching this

anymore?

Barry

Sure. *It's a good exercise for proficiency and confidence building.
Touch and goes, taxiing and even turning at runway intersection to
take off on a different runway. *Good communication, experienced tow
pilots, proper conditions, *FUN!


Why all CFIG's (in the USA) must discuss and teach this maneuver: It
appears in your FAA Practical Test Standards (PTS) for Glider
"checkrides" under the Area of Operation "Launches and Landings"/
"Abnormal Occurrences" / "Glider and towplane release
failure" (meaning both releases fail.) This is one of five listed
abnormal situations in your FAA PTS. FAA allows the Examiner to ask
you to perform this maneuver, as the Examiner may ask you to perform
any or all of the tasks under "Abnormal Occurrences." Most Examiners
just ask for the "towline break" demonstration and the "glider (only)
release failure" signal on tow, but "double release" is part of the
PTS, so be prepared to at least discuss the procedure on your
checkride.

Note to CFIG's: Just because a double release failure is rare does
not mean you can skip over it in the PTS. The FAA discusses double
release failure in the FAA Glider Flying Handbook, Chapter 7. Not
much of a discussion however, but there it is. Towpilots need to be
thoroughly briefed by a towpilot who has flown this maneuver. The
descent is very gradual at a proper approach airspeed. If the
approach doesn't look or feel right, the towpilot has the option to go
around and climb with glider still in tow.

Note to Readers: My discussion posted here is abbreviated and not
complete and not to be substituted or used for any aspect of your
ground and flight instruction. This post is discussion, not
instruction.

Regarding the glider in "low tow" position: Because the towplane is
gradually descending the wake is relatively higher, so the glider does
not need to be too low in relation to the towplane. The sight picture
is usually not as low as when you box the wake -- just enough to be
just under the wake, and with a full view of the towrope. Keep the
airbrakes unlocked and deployed as needed to keep a tight towrope at
all times. Overrunning the towplane is the dangerous part both in the
air and on the ground roll out. Be ready to release.

Important Timing Aspect: The glider (in low tow) must not touch down
much before the towplane -- this can be a hazardous aspect -- touching
down well before the towplane and stalling it. The glider wings are
still carrying the weight of the glider while it is flying. Once the
glider touches the wings stop lifting and the glider creates more
weight drag on the towplane, which if still well above the runway will
be slowed and may stall. If you try this maneuver, keep the glider
flying until the towplane is about one meter above the runway. Make
sure the towpilot keeps the towplane moving forward (no brakes) with
some power to help keep the rope tight. Glider pilot deploys nearly
full airbrake (spoiler) to keep from lifting off again and some wheel
brake, AFTER the towplane is on the ground. Just roll out and not be
in a hurry to stop. Both pilots should release if slack rope
develops. If lots of runway ahead a touch and go is possible. Long
runways and a good headwind make landing on tow a bit less
challenging. A long towrope may be a good idea.

For the most comprehensive discussion and training on landing on tow,
along with purposely breaking the towrope, contact Cindy & Marty at
Caracole Soaring in California. They have developed this procedure to
be relatively safe, and fun.

Remember, I am not your personal Flight Instructor here. My
discussion posted here is abbreviated and not complete and not to be
used as part of your ground and flight instruction. For more
instruction in "abnormal occurrences" on tow consult with your local
Certificated Flight Instructor, one who is proficient in landing on
tow. You, your Flight Instructor, Towpilot, and FAA Examiner must
determine the level of acceptable risk when performing this or any
maneuver. You decide if you want to fly a "landing on tow", and don't
blame me if you screw it up.

On Sep 8, 7:13*am, FBCompton wrote:
On Sep 7, 11:21*pm, wrote:

**Is anyone teaching this

anymore?

Barry

Sure. *It's a good exercise for proficiency and confidence building.
Touch and goes, taxiing and even turning at runway intersection to
take off on a different runway. *Good communication, experienced tow
pilots, proper conditions, *FUN!

Why all CFIG's (in the USA) must discuss and teach this maneuver: *It
appears in your FAA Practical Test Standards (PTS) for Glider
"checkrides" under the Area of Operation "Launches and Landings"/
"Abnormal Occurrences" / "Glider and towplane release
failure" (meaning both releases fail.) *This is one of five listed
abnormal situations in your FAA PTS. *FAA allows the Examiner to ask
you to perform this maneuver, as the Examiner may ask you to perform
any or all of the tasks under "Abnormal Occurrences." *Most Examiners
just ask for the "towline break" demonstration and the "glider (only)
release failure" signal on tow, but "double release" is part of the
PTS, so be prepared to at least discuss the procedure on your
checkride.

Note to CFIG's: *Just because a double release failure is rare does
not mean you can skip over it in the PTS. * The FAA discusses double
release failure in the FAA Glider Flying Handbook, Chapter 7. *Not
much of a discussion however, but there it is. * Towpilots need to be
thoroughly briefed by a towpilot who has flown this maneuver. *The
descent is very gradual at a proper approach airspeed. *If the
approach doesn't look or feel right, the towpilot has the option to go
around and climb with glider still in tow.

Note to Readers: *My discussion posted here is abbreviated and not
complete and not to be substituted or used for any aspect of your
ground and flight instruction. *This post is discussion, not
instruction.

Regarding the glider in "low tow" position: *Because the towplane is
gradually descending the wake is relatively higher, so the glider does
not need to be too low in relation to the towplane. *The sight picture
is usually not as low as when you box the wake -- just enough to be
just under the wake, and with a full view of the towrope. *Keep the
airbrakes unlocked and deployed as needed to keep a tight towrope at
all times. Overrunning the towplane is the dangerous part both in the
air and on the ground roll out. *Be ready to release.

Important Timing Aspect: *The glider (in low tow) must not touch down
much before the towplane -- this can be a hazardous aspect -- touching
down well before the towplane and stalling it. *The glider wings are
still carrying the weight of the glider while it is flying. *Once the
glider touches the wings stop lifting and the glider creates more
weight drag on the towplane, which if still well above the runway will
be slowed and may stall. *If you try this maneuver, keep the glider
flying until the towplane is about one meter above the runway. *Make
sure the towpilot keeps the towplane moving forward (no brakes) with
some power to help keep the rope tight. *Glider pilot deploys nearly
full airbrake (spoiler) to keep from lifting off again and some wheel
brake, AFTER the towplane is on the ground. *Just roll out and not be
in a hurry to stop. *Both pilots should release if slack rope
develops. *If lots of runway ahead a touch and go is possible. *Long
runways and a good headwind make landing on tow a bit less
challenging. *A long towrope may be a good idea.

For the most comprehensive discussion and training on landing on tow,
along with purposely breaking the towrope, contact Cindy & Marty at
Caracole Soaring in California. *They have developed this procedure to
be relatively safe, and fun.

Remember, I am not your personal Flight Instructor here. *My
discussion posted here is abbreviated and not complete and not to be
used as part of your ground and flight instruction. * For more
instruction in "abnormal occurrences" on tow consult with your local
Certificated Flight Instructor, one who is proficient in landing on
tow. *You, your Flight Instructor, Towpilot, and FAA Examiner must
determine the level of acceptable risk when performing this or any
maneuver. *You decide if you want to fly a "landing on tow", and don't
blame me if you screw it up.

How much runway do you normally consume before both towplane and
glider come to a safe stop? I realize field elevation, density
altitude, wind,
obstructions, type of towplane and glider, are all variables. We have
a 3000ft dirt strip at 780ft MSL
field elevation, but have barbed wire fences to clear at both ends and
a ditch on one end. Is that enough to do it comfortably?

Just to add two thoughts- 1) the wake is more mild as the tug is
generating less power, 2) it worked best for me (and this is how I was
taught) if the sailplane controls the descent rate and the towplane
controls the speed. This division of duties prevents the towplane from
landing too short. Also, at towplane final approach speed, the glider
will be well above stall and clearly not ready to land. Thus it is
natural for the glider pilot to keep it flying and apply just enough
spoilers are needed at this point to keep the rope taught. The
maneuver is uneventful if properly planned out, but it does eat up lot
of runway.

Chad
4Z

At 14:13 08 September 2009, FBCompton wrote:

Important Timing Aspect: The glider (in low tow) must not touch down
much before the towplane -- this can be a hazardous aspect -- touching
down well before the towplane and stalling it. The glider wings are
still carrying the weight of the glider while it is flying. Once the
glider touches the wings stop lifting and the glider creates more
weight drag on the towplane, which if still well above the runway will
be slowed and may stall.

This seems counterintuitive to me. When the wings stop lifting, the
induced drag goes away, so the drag on the towplane should decrease. The
only added drag is friction in the glider's main gear. What am I missing
here?

Jim Beckman

Sounds like it's time for a Landings On Tow Soar-O-Rama on El Mirage
dry lake!
Jim

On Sep 9, 9:27*am, JS wrote:
Sounds like it's time for a Landings On Tow Soar-O-Rama on El Mirage
dry lake!
Jim

Yeehaa! Confidence building, fun and entertaining, useful for XC
tows. I'm up for the LOT Soar-O-Rama (followed of course by awesome
dry lake food, campfire, and telling of lies), but probably not at El
Mirage. Last time I was there, the lakebed was being patrolled by 6
Big Land Mothers in large SUV's. Not the same atmosphere as it was in
the 60's and 70's. How about Roach?

In article Jim Beckman writes:
At 14:13 08 September 2009, FBCompton wrote:

Important Timing Aspect: The glider (in low tow) must not touch down
much before the towplane -- this can be a hazardous aspect -- touching
down well before the towplane and stalling it. The glider wings are
still carrying the weight of the glider while it is flying. Once the
glider touches the wings stop lifting and the glider creates more
weight drag on the towplane, which if still well above the runway will
be slowed and may stall.

This seems counterintuitive to me. When the wings stop lifting, the
induced drag goes away, so the drag on the towplane should decrease. The
only added drag is friction in the glider's main gear. What am I missing
here?

Jim Beckman

It seems backwards to me, too, but I have asked tow pilots about this,
and I was told that they feel the drag decrease when the glider comes off
the ground on the takeoff roll.

I guess those wheels have a lot of drag.

Alan