Wave Off on Early Tow Question

(Michael Pitoniak) wrote in message . com...
Folks,

(snip)
I imagine
(snip)
it is worth considering all possible senarios.


And you have the right idea! There are just too many variables to
settle on a standard, universal solution. From the glider end, it's
"generally" better to turn upwind after a low PT3 but there are places
where terrain or obstructions may render that a poor choice, and days
or moments of the day in which traffic or other considerations can
render the upwind turn or even turning around at all the worst
possible thing to do. Considering all possible scenarios equips you
with a mental emergency procedures flip-chart. As variables influence
the departure from the beginning of the takeoff to the point at which
you or the towplane have reason to part company, you're much more
likely to find yourself on the right page for the moment than the
pilot who has never imagined in detail what might ensue.

There are a number of good reasons for the towplane to go pretty
nearly straight ahead after a low altitude power failure, but it isn't
always going to happen that way. We airplane drivers were all trained
never to turn back, but there's ample evidence (largely in the form of
accident statistics) that the training wasn't universally effective.
There are also a number excellent mitigating circumstances that might
make it attractive for the towplane to turn back; e.g., he's already
started a turn below 200'AGL and doesn't need to completely reverse
course to get there (and the good reasons for that turn could fill
another thread).

Towplane power failures aren't the only valid reason for parting
company at critically low altitude, either. I've signalled wave-offs
and/or pickled the front end of the rope from a perfectly functioning
towplane because 1) the combination wasn't outclimbing otherwise
unavoidable terrain or obstructions for reason other than power
failure; 2)the towplane and glider were better able to avoid a midair
collision with other aircraft by maneuevering independently; and 3), I
didn't think I could tow and deal with undesireable and previously
undiscovered critters in the cockpit all at the same time.

The towpilot may wave you off... will more likely just pickle the
rope; and may not get around to doing either one. (I've seen it all
three ways from both ends of the rope, under circumstances both
appropriate and otherwise).

FAR 91.-umpty-ump requres an agreement between the towplane and glider
pilots as to signals and courses of action blah-blah, which is
commonly satisfied by field check discussions or printed handouts on
standard operating procedures peculiar to the flying site. We often
get more specific with pre-takeoff requests for a particular speed or
direction of tow, but operational considerations or variables may
obviate complete agreement on every contingency before every tow. As
to the specifics of what a given towpilot's gonna do at a given flying
site on a given day when the powerplant sucks in a valve, get there
before or stick around after the busy core of his (or her) flying day
and ask. The towpilot is almost certain to be delighted that you give
a rip.

Cheers,
Eric
"Plan ahead, stay alert, and never carry a package by the string"

"Eric Coleson" wrote in message


And you have the right idea! There are just too many variables to
settle on a standard, universal solution. From the glider end, it's
"generally" better to turn upwind after a low PT3 but there are places
where terrain or obstructions may render that a poor choice, and days
or moments of the day in which traffic or other considerations can
render the upwind turn or even turning around at all the worst
possible thing to do. Considering all possible scenarios equips you
with a mental emergency procedures flip-chart. As variables influence
the departure from the beginning of the takeoff to the point at which
you or the towplane have reason to part company, you're much more
likely to find yourself on the right page for the moment than the
pilot who has never imagined in detail what might ensue.

There are a number of good reasons for the towplane to go pretty
nearly straight ahead after a low altitude power failure, but it isn't
always going to happen that way. We airplane drivers were all trained
never to turn back, but there's ample evidence (largely in the form of
accident statistics) that the training wasn't universally effective.
There are also a number excellent mitigating circumstances that might
make it attractive for the towplane to turn back; e.g., he's already
started a turn below 200'AGL and doesn't need to completely reverse
course to get there (and the good reasons for that turn could fill
another thread).

Towplane power failures aren't the only valid reason for parting
company at critically low altitude, either. I've signalled wave-offs
and/or pickled the front end of the rope from a perfectly functioning
towplane because 1) the combination wasn't outclimbing otherwise
unavoidable terrain or obstructions for reason other than power
failure; 2)the towplane and glider were better able to avoid a midair
collision with other aircraft by maneuevering independently; and 3), I
didn't think I could tow and deal with undesireable and previously
undiscovered critters in the cockpit all at the same time.

The towpilot may wave you off... will more likely just pickle the
rope; and may not get around to doing either one. (I've seen it all
three ways from both ends of the rope, under circumstances both
appropriate and otherwise).

FAR 91.-umpty-ump requres an agreement between the towplane and glider
pilots as to signals and courses of action blah-blah, which is
commonly satisfied by field check discussions or printed handouts on
standard operating procedures peculiar to the flying site. We often
get more specific with pre-takeoff requests for a particular speed or
direction of tow, but operational considerations or variables may
obviate complete agreement on every contingency before every tow. As
to the specifics of what a given towpilot's gonna do at a given flying
site on a given day when the powerplant sucks in a valve, get there
before or stick around after the busy core of his (or her) flying day
and ask. The towpilot is almost certain to be delighted that you give
a rip.

Cheers,
Eric
"Plan ahead, stay alert, and never carry a package by the string"

Good analysis and good post, Eric.

Premature termination of an airtow at a critically low altitude is a deadly
serious business for both the glider and tug. Add a big heavy glider with
water ballast that must be dumped before landing and the options get even
narrower.

As I have often said, a critical examination of all the risks makes air tow
look less safe and winch launch look better and better.

Bill Daniels