Double Release Failure

We lost Captain Curt in Blairstown to a tug upset. Preferring to
stay away from that possibility. I have done quite a few landings on
tow and would gladly do one in about anything I'm familiar with.
Perhaps people who believe that landings on tow are dangerous haven't
done one?
After one LOT in an AS-K21 (during my Commercial check ride prep
with the instructor in the back seat) with tension still on the rope,
the rope would not release from the glider. It turned out the ring was
smaller diameter than standard and the release didn't open enough to
go past center. It would have released in flight, but sitting still it
wouldn't. How far from an in-flight problem was that? New Tost rings
were ordered, and the release cable adjusted.
Jim

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

Aarrgh! Not this subject again! Winter must be coming There have
been monsterous threads about this subject but a search sadly yielded
nada.

First, ZZ, what is the "additional risk" as compared to a departure,
other than the fact that the Landing On Tow ("LOT") is losing energy
(altitude + airspeed) and a takeoff is gaining energy? LOT is just
another phase of tow, a descending one, culminating in a touchdown.

Second, other than the incident JS mentions and the double failure Tom
Knauff alludes to, I am not aware of any dual failures. These
statistics do no support LOT's as preparation for such an event.
However, I DO believe they have value and are worth the perceived risk
in terms of confidence building and (heaven forbid) Fun and
Excitement. I think the military calls such events "motivational".
Skylark used to employ this event as a pre-solo wind-up for students.
A sortie consisted of a CFI demo'd touch-and-go followed by a student
touch-and-go and finally a student full stop. The post-flight grin
and swagger exhibited by the student was indeed worth it. Earned
Confidence is a Good Thing, as is Fun and Excitement.

Nothing special is required of the glider pilot and very little of the
Tuggie to LOT: After steering the flight to overhead the airport at
more than 1500 ft agl and after exchanging appropriate signals, the
glider pilot pulls full brakes (no wheel brakes!) and continues to fly
the standard high tow position. The Tuggie needs to keep the
formation in glide range of the field. Who touches down first is not
important. Just land your aircraft. The glider need only flair and
land as usual and just keep the rope taught on the ground using wheel
brake as the tug brakes to a stop. As conducted at Skylark, the
Tuggie maintained an approach of 65 kts for 2-33 and 70 kts for glass
and was shooting for 4-5 kt descent rate by adjusting power. Power
was smoothly and slowly reduced as the ground came up and the Tug
wheel-landed. Short of locking the brakes,wrecking the tug, and/or
loss of glider wheel brakes, it is highly unlikely that the glider
will overrun the Tug. If it occurs, the glider clears to the right
per standard procedure. If the approach becomes unacceptable, the
Tuggies applies full power to initiate the go around and the glider
puts the brakes away as the descent stops. If the glider puts the
brakes away at any point in the approach, the tuggie initiates a go-
around and transitions to a standard climb. I have never observed a
rejected approach.

100's (1000's?) of these have been flown at Skylark, many (most) with
pre-solo pilots flying. The only problem I observed in 20 years of
doing these was when the glider pilot decided to ignore the briefed
procedures and began modulating the dive brakes in a Blanik, thus
destabilizing the approach. Typical field length used was about 3000
ft (of 5K ft available), over a 30 ft (?) obstacle at 4200 ft msl.
Typical density altitudes are probably in the 5000 ft msl range.

I have also observed (as the Tuggie) intentional rope breaks ("IRB")
performed by experts and, as others have mentioned, it is also not a
big deal. I have also experienced attempts by Noobs that were
decidedly unpleasant, to the point of punching them off. My biggest
issue with IRB's is the difficulty in maintaining proficiency; how
many ropes / weak links is an operator going to allow each pilot to
break per year?

LOT's in summary:

* More dangerous than a departure tow? Maybe slightly more - mostly
due to a lack of practice and experience.

* Necessary preparation for a real emergency? Definitely not worth
it.

* Valuable for improving pilot skills and inspiring self-confidence?
Invaluable!

A good tool in the toolbox for cruise descents on X-C tows?
Invaluable!

* Fun and Exciting? Absolutely!

At 04:41 09 September 2009, wrote:

Nothing special is required of the glider pilot and very little of the
Tuggie to LOT: After steering the flight to overhead the airport at
more than 1500 ft agl and after exchanging appropriate signals, the
glider pilot pulls full brakes (no wheel brakes!) and continues to fly
the standard high tow position.

Hadn't thought about this much, but what's the procedure when I'm
flying my 1-35? About the same, I suppose, although the transition from
zero to full flaps while on tow might be sort of entertaining. Full flaps
right away, or keep a bit in reserve? I wonder what the glider attitude
would look like while running along at tow speed with all the flaps out?
Has anybody tried this in such a glider?

Jim Beckman

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

wrote:
Aarrgh! Not this subject again! Winter must be coming There have
been monsterous threads about this subject but a search sadly yielded
nada.

First, ZZ, what is the "additional risk" as compared to a departure,
other than the fact that the Landing On Tow ("LOT") is losing energy
(altitude + airspeed) and a takeoff is gaining energy? LOT is just
another phase of tow, a descending one, culminating in a touchdown.

Second, other than the incident JS mentions and the double failure Tom
Knauff alludes to, I am not aware of any dual failures. These
statistics do no support LOT's as preparation for such an event.
However, I DO believe they have value and are worth the perceived risk
in terms of confidence building and (heaven forbid) Fun and
Excitement. I think the military calls such events "motivational".
Skylark used to employ this event as a pre-solo wind-up for students.
A sortie consisted of a CFI demo'd touch-and-go followed by a student
touch-and-go and finally a student full stop. The post-flight grin
and swagger exhibited by the student was indeed worth it. Earned
Confidence is a Good Thing, as is Fun and Excitement.

Nothing special is required of the glider pilot and very little of the
Tuggie to LOT: After steering the flight to overhead the airport at
more than 1500 ft agl and after exchanging appropriate signals, the
glider pilot pulls full brakes (no wheel brakes!) and continues to fly
the standard high tow position. The Tuggie needs to keep the
formation in glide range of the field. Who touches down first is not
important. Just land your aircraft. The glider need only flair and
land as usual and just keep the rope taught on the ground using wheel
brake as the tug brakes to a stop. As conducted at Skylark, the
Tuggie maintained an approach of 65 kts for 2-33 and 70 kts for glass
and was shooting for 4-5 kt descent rate by adjusting power. Power
was smoothly and slowly reduced as the ground came up and the Tug
wheel-landed. Short of locking the brakes,wrecking the tug, and/or
loss of glider wheel brakes, it is highly unlikely that the glider
will overrun the Tug. If it occurs, the glider clears to the right
per standard procedure. If the approach becomes unacceptable, the
Tuggies applies full power to initiate the go around and the glider
puts the brakes away as the descent stops. If the glider puts the
brakes away at any point in the approach, the tuggie initiates a go-
around and transitions to a standard climb. I have never observed a
rejected approach.

100's (1000's?) of these have been flown at Skylark, many (most) with
pre-solo pilots flying. The only problem I observed in 20 years of
doing these was when the glider pilot decided to ignore the briefed
procedures and began modulating the dive brakes in a Blanik, thus
destabilizing the approach. Typical field length used was about 3000
ft (of 5K ft available), over a 30 ft (?) obstacle at 4200 ft msl.
Typical density altitudes are probably in the 5000 ft msl range.

I have also observed (as the Tuggie) intentional rope breaks ("IRB")
performed by experts and, as others have mentioned, it is also not a
big deal. I have also experienced attempts by Noobs that were
decidedly unpleasant, to the point of punching them off. My biggest
issue with IRB's is the difficulty in maintaining proficiency; how
many ropes / weak links is an operator going to allow each pilot to
break per year?

LOT's in summary:

* More dangerous than a departure tow? Maybe slightly more - mostly
due to a lack of practice and experience.

* Necessary preparation for a real emergency? Definitely not worth
it.

* Valuable for improving pilot skills and inspiring self-confidence?
Invaluable!

A good tool in the toolbox for cruise descents on X-C tows?
Invaluable!

* Fun and Exciting? Absolutely!



I agree with your assessments Mark. I have only done three LOTs and they
were all easy and great fun.

A current student of mine asked me how common the double release failure
is and I did not have a good answer for him so I decided to poll the
masses. The answer to that one seems to be either zero or one.

Regarding the question of should we be practicing these, I am currently
bucking a political tide trying to get LOTs into Flight Reviews
for those pilots that want to widen their horizons. So far, no dice.

I especially liked your point about cruise descents on X-C tows.
Descending on tow is not something we do normally and while not
difficult, requires some thought and care.

Paul
ZZ

In article ZZ writes:

I agree with your assessments Mark. I have only done three LOTs and they
were all easy and great fun.

A current student of mine asked me how common the double release failure
is and I did not have a good answer for him so I decided to poll the
masses. The answer to that one seems to be either zero or one.

Regarding the question of should we be practicing these, I am currently
bucking a political tide trying to get LOTs into Flight Reviews
for those pilots that want to widen their horizons. So far, no dice.


No reason to put them in flight reviews, since the trend is to make the
flight review more closely match the PTS. Now, I think that making the
flight review be matched to the Practical Test Standards is stupid, and it
makes a lot more sense to use the time working on something *different*,
and let the evaluation of general competency be incidental --- a good
instructor should be able to tell if the pilot is generally competent
fairly quickly, without having to go through a re-running of the checkride.

For example, it would make more sense for me to spend a bunch of flight
review time under a hood, since I am not instrument rated, so I have not
practiced that lately. Or, perhaps do it on a soft/grass field, since
most of my flying has been on pavement. Doing it in a different sort of
airplane would be another option.

Landing on tow as one option for a flight review is fine. It should
*not* be a standard part, however.

Putting specific items in the flight review is a bad idea. Doing something
different, gaining new experience, is better than re-doing the same experience.

Alan

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

On Sep 10, 2:37*am, (Alan) wrote:
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

Behind less powerful tow planes, I generally note a 3-5 knot jump in
airspeed immediately following glider lift off.

Frank Whiteley