mart wrote:
Snip...

Now the problems started. While putting the airbrakes away the flaps
slipped to negative. Not very handy at 20 feet and relatively slow.
The glider promptly stalled.

You've probably already gleaned 'the obvious' lessons from this
incident, but - hoping to not be beating a dead horse for others who may
not yet have - here's my take. (A 'take' wholly ignorant of how the
LS-6's flap/airbrake system is *supposed* to work, incidentally...but a
take with 2k hours on 3-different flaps-only gliders, meaning each had
differing 'monkey motion' mechanical/hydraulic systems powering the
flaps, & only one ship of which had reflexing flaps...)

In a nutshell, never assume you know everything about how a system - any
system - is supposed to work without spending 'considerable time'
physically examining its realities. Of course, reading about it is good
too...but not wholly sufficient.

Never carry a package by the string...by which I'm suggesting all
mechanical locks should be viewed with a jaundiced eye, whether a gear
downlock, flap detent, or whatever. Locks wear. Some aren't even locks,
but rather 'suspenders' to another 'belt' somewhere. (My current ship's
'apparent' gear downlock falls into that category, according to the
designer.) Don't court failure...but be prepared for it. Use
'suspenders' where you can.
- - - -


He than did what he was thought by a test pilot." If everything goes
to ****, reverse the last thing you have done."

Excellent advice...if a person has the time/wits to apply it.
- - - -


So contrary to what you would normally do when stalled, which is to
push the nose over , he pulled the brakes again, which in turn pulled
the flaps out again. He said that it saved his bacon. Took out the
undercarriage and hurt his back, but he walked away.

Even in the absence of being able to deploy spoilers (and - he hoped -
flaps again prior to contacting the ground, i.e. your adviser), my
working conclusion is radically changing fuselage pitch angle (via
radical stick movements) near the ground is generally A Really Bad Thing
To Do. Even if a thoughtful person gets away with it without pranging
something, s/he'll come away with a deeper understanding of what happens
in the short term when one reduces wing angle of attack. Stated another
way, doing this near the ground is a 'good' way to learn that stick
*directly* controls angle of attack, and only indirectly, speed. Guess
which one changes first when you put stick forward close to the deck?

A stall at 20-feet agl is basically unrecoverable via stick input *only*
for the gliders we fly. The only salvation *might* be changing wing
angle of attack via camber change (if an option). In the absence of
complicating flaps, closing spoilers is advisable, too, natch.

Your adviser 'got away with' what would appear to be a rare-enough
situation, to be sure...

Had he not known of the 'reverse what you last did' advice, and instead
attempted to recover via forward stick, my money woulda been placed on
him whacking the ground at a steeper deck angle, harder.

And with the advantage of time and hindsight, had he simply pulled on
flaps (rather than hoping they came back with spoiler activation), it's
*possible* his arrival might have been less abrupt. As always, the devil
is in the details. Only thoughtfully checking your ship can allow you to
most sensibly decide for yourself which approach would have been 'ideal'
in your adviser's situation.
- - - -


I thought I should share it with you just in
case.

cheers,

Mart

VH-NII

Thanks for sharing!!!

Regards,
Bob W.