How to do a Positive Control Check?

wrote:

Please name one accident of a glider with auto hookups that could have
been prevented by a positive control check. I sure don't know any. A
seized bearing will be detected by simply moving the stick. In all
gliders I know there is no scenario of control failure that would
necessitate a positive control check for detection.

Well, a few years ago I had an 'incident' with a glider with automatic
hookups that passed two positive control checks.

The elevator hookup on the DG1000 has a little label beside it that
says that the trim must be fully forward when the elevator is
attached to the tail. The hookup requires a small bearing to fit into
a channel.

On the first flight of the season the second season I had the glider
I rigged it without putting the trim full forward. I wasn't happy
with it, but couldn't see what was wrong. I got an experienced pilot
for was nearby to do a positive control check with me. We couldn't
see anything wrong.

I towed out and gridded. On the grid I still felt there was something
wrong, but couldn't put my finger on what was wrong. I asked another
experienced pilot to do a control check before I launched. We found
nothing wrong.

As soon as the tow commenced I could see what the problem was. I
only had approx half stick movement. The stick was hard against
the back stop on tow. I towed high, dumped my ballast and returned
to the field. With the stick full back I could get the speed back
to 60knots. I landed OK. We removed the tail, pushed the trim
forward, rerigged, and all was fine.

Lack of familiarity with the rigging bit me that time.

There is no silver bullet. You must always be aware of the
specific requirements and problems of whatever equipment
you are using.


--
Philip Plane _____
|
---------------( )---------------
Glider pilots have no visible means of support

I towed out and gridded. On the grid I still felt there was something
wrong, but couldn't put my finger on what was wrong. I asked another
experienced pilot to do a control check before I launched. We found
nothing wrong.

In between this last paragraph and the text below, did you go through
a pre-flight checklist, that had a C for "CONTROLS, CLEAR AND FREE-
FULL MOVEMENT? Or did the problem not manifest itself until full
flight?

As soon as the tow commenced I could see what the problem was. I
only had approx half stick movement.

Umm, pop the cord? Did you not also have an E somewhere on your
preflight checklist, for EMERGENCY, which in theory should have left
you with clear options for aborting a takeoff at different phases? I
realize that the layout of the airport this happened at may not have
good emergency options and also that it may not have occurred until
already past the "point of no return" so these points may be moot and
your actions taken executed flawlessly (after all, you are here to
tell about it...), so I don't mean to harp. I'm just curious if this
particular frightening occurrence could have been avoided altogether
or at least handled at MUCH lower energies if a thorough preflight
checklist was actually performed. Thanks for sharing.

Paul Hanson

On Tue, 3 Jun 2008 19:43:51 -0700 (PDT), wrote:

Please name one accident of a glider with auto hookups that could have
been prevented by a positive control check. I sure don't know any. A
seized bearing will be detected by simply moving the stick. In all
gliders I know there is no scenario of control failure that would
necessitate a positive control check for detection.

There have been SEVERAL incidents and accidents of DG gliders where
the automatic hookup of the elevator was not connected correctly.

Not to mention several (unfortunately usually fatal) crashes of
gliders where the auto hookups were connected correctly, but the
horizontal tail was not. Ernst-Gernot Peter and Clem Bowman come to my
mind...

You are making a slippery slope argument. Should we mandate annual
stress tests of wings in the name of safety? Overhaul all tost
releases every 100 cycles?

Nope... but to do a simple 2 minute check before the flight...


Bye
Andreas

Guys you are missing the point! There is a difference between a
Critical Assembly Check and a Positive Control Check. A PCC would NOT
have helped Clem. With the elevator connecting bolt taped over, the
glider would have most likely passed the PCC! I am all in favor of
doing the Critical Assembly Check. I always do mine twice, first after
rigging, second before launch. Of all of the accidents described, most
would have been avoided by doing a proper CAC, not PCC!

On Jun 4, 8:56*am, Andreas Maurer wrote:
On Tue, 3 Jun 2008 19:43:51 -0700 (PDT), wrote:
Please name one accident of a glider with auto hookups that could have
been prevented by a positive control check. I sure don't know any. A
seized bearing will be detected by simply moving the stick. In all
gliders I know there is no scenario of control failure that would
necessitate a positive control check for detection.

There have been SEVERAL incidents and accidents of DG gliders where
the automatic hookup of the elevator was not connected correctly.

Not to mention several (unfortunately usually fatal) crashes of
gliders where the auto hookups were connected correctly, but the
horizontal tail was not. Ernst-Gernot Peter and Clem Bowman come to my
mind...

You are making a slippery slope argument. Should we mandate annual
stress tests of wings in the name of safety? Overhaul all tost
releases every 100 cycles?

Nope... but to do a simple 2 minute check before the flight...

Bye
Andreas

On Jun 3, 7:43*pm, wrote:
Please name one accident of a glider with auto hookups that could have
been prevented by a positive control check. I sure don't know any.

Clem Bowman, Genesis 2, Minden Nationals.................pilot didn't
fully seat the locking mechanism on the elevator because he had given
the little red tool to his wife so she could put water in the
wings..........................didn't do a critical assembly
check..................elevator fell off during take-
off.........................Clem is no longer with us!
JJ

On Jun 3, 7:43*pm, wrote:
Please name one accident of a glider with auto hookups that could have
been prevented by a positive control check.

Russia elevator. Air Sailing contest. Pilot Chad Moore. Broken
elevator pintle discovered. Accident averted.

Thanks, Bob K.

On Jun 4, 8:48*am, Bob Kuykendall wrote:
On Jun 3, 7:43*pm, wrote:

Please name one accident of a glider with auto hookups that could have
been prevented by a positive control check.

Russia elevator. Air Sailing contest. Pilot Chad Moore. Broken
elevator pintle discovered. Accident averted.

Thanks, Bob K.

Russia pilot, at North Plains Oregon discovered broken rudder
connection (I can't remember if it was a control horn problem or
cables) while doing a PCC. He was glad he did!

wrote:
Please name one accident of a glider with auto hookups that could have
been prevented by a positive control check. I sure don't know any. A
seized bearing will be detected by simply moving the stick. In all
gliders I know there is no scenario of control failure that would
necessitate a positive control check for detection.

Lots of food for serious thought in this thread.

Having flown/flying (since 1981) a ship with auto-connects everywhere,
but one loose pin (the main one) anywhere, locking mechanisms (for
all-flying stab/main pin) in open/plain sight, and (for all practical
purposes) impossible to safety the wings without
bending/crushing/breaking something in the auto-connect systems, the
only control failure I've (yet) had, occurred - progressively - in
flight...on the one control never routinely disconnected. (The weldment
in the rudder actuation system that converts rudder cable motion to
pushrod motion to the rudder began to fail; by the time I got it
diagnosed and [uneventfully] landed [after a pattern sized so the
absence of a rudder would not have been a problem], the weldment was
nearly in two pieces and the rudder [gently] fluttering with large
displacements at low-frequency.)

If I didn't previously believe Murphy was real (which I did!), this
incident would have removed all doubt. I guess my main point here is,
if it happens it must be possible...combine that reality with Murphy and
the certainties in life become fuzzier.

Methinks (annual/daily inspections notwithstanding) skepticism when it
comes to the structural integrity of one's sailplane is a likely a wiser
approach than blindly trusting certitude...


You are making a slippery slope argument. Should we mandate annual
stress tests of wings in the name of safety? Overhaul all tost
releases every 100 cycles?

I don't argue the point(s) immeedjutly above. Life itself is a risk.
Certainty is not an option...although the belief in it, is.

Respectfully,
Bob W.

On 4 Jun, 03:26, "noel.wade" wrote:
On Jun 3, 7:18*pm, wrote:

For ships with *auto hookups* positive control checks are a waste of
time, and in fact do more harm then good. I have never heard of a

I cannot believe this was posted. *Its YOUR airplane. *YOU are the
Pilot in Command. *YOU have the responsibility to ensure that the
checks are done properly and by someone who can do it without damage
to the aircraft.

It sounds to me as if that's what he's doing: taking responsibility
for the checks which are done. It's just that he doesn't believe some
checks need doing, or doing in a particular way.

After all, he's going to be the one in trouble if he's wrong. But it
would be interesting to hear of a real case where a glider with
automatic connections has had a problem discovered during the positive
control check. Anyone?

Ian

PS I do 'em myself. But then, my glider doesn't have automatic
connections. I think I'd still do them then, though.

Ian wrote:
After all, he's going to be the one in trouble if he's wrong. But it
would be interesting to hear of a real case where a glider with
automatic connections has had a problem discovered during the positive
control check. Anyone?

Just about any DG (already mentioned): possible to get horizontal stab
on and secured with elevator pushrod outside of receptacle, resulting in
reduced range of elevator movement and binding. Only managed to do this
once.

Duo Discus: possible to get horizontal stab on and secured with elevator
drive pins jammed in-between torque tube and upper elevator skin, rather
than in the receiving wholes on the torque tube, resulting in reduced
range of movement and funny stick feel.

LAK-17A: Possible to get wings and secured on with one control (I think
it was aileron) disconnected, resulting funny stick feel and no surface
movement. Never figured out how I managed to do that, and it never
happened again.

Ventus B: Possible to get wing on and secured with one control pushrod
end (aileron again?) outside of socket and jammed into fuselage opening,
resulting in no surface movement and binding. This area was apparently
changed at least once during the production run.

Marc