assembly interruption a dangerous thing

On May 22, 12:43*pm, danlj wrote:
Dear List,

From time to time a pilot is broken or totalled because assembly was
in some way incomplete. I'm simply writing to remind us all not to
permit ourselves to be involved in conversation, however well-
intended, during assembly.

This is motivated by the fact that I discovered that the wing root
tape IS sufficient to hold the right wing onto a Ventus when the main
spar pin is not fully engaged. This discovery was sufficiently
humiliating that I have waited for a few days to confess.

The hookups of the Ventus are brain-dead simple and foolproof, except
that the locking pins really do need to be engaged.

Sometimes I have forgotten to pull off the wing-root tape before
trying to remove the wings during disassembly, which has sparked one
of those random fantastical thoughts, "I wonder if the main spar pin
is really needed."

I normally assemble completely alone; one day last week a friend came
along to see the glider and wanted to 'help' assemble, and of course
happens to be one of those wonderfully friendly, fascinating, chatty
types.

During the latter part of the subsequent 2-hour flight, I heard a
faint low rumble from behind, making me wonder if the engine
compartment doors had fully closed.

After I landed, I discovered that the tape over the right wing root
gap was still fully covering the gap, but the gap had widened from the
usual 2mm to about 5 mm. I need hardly tell you the sense of fright
and self-abasement this inspired.

I immediately realized that I had failed to push the main spar pin
'home' - normally the sequence is to put it halfway through (into the
left spar) to hold the left wing in place while the right wing is
installed, then go straightaway and push it home. In this case an
interruption to correct wing-taping being done by my 'assistant'
caused this step to be skipped.

I recall an old suggestion that pilots should wear a red cap as a
signal not to be interrupted. But the signal won't be obeyed until
it's learned. Maybe a more effective device would be to screen-print
words on the front and back of a light vest to be worn during
assembly, perhaps
*"DEAF" - or
"Shut up (please)"

But of course the real discipline is with us assemblers, to not permit
interruptions, and to say to the first person who offers to help,
"Yes, you can help by preventing anyone from talking to me until this
is done."

Dan Johnson

Thanks for sharing this Dan.

I love your simple answer to the eager helpers.... "you can help by
preventing anyone from talking to me until this is done." After a
while the eager helpers will get the idea.

Curt Lewis - 95

On May 22, 7:51 pm, CLewis95 wrote:
On May 22, 12:43 pm, danlj wrote:



Dear List,

From time to time a pilot is broken or totalled because assembly was
in some way incomplete. I'm simply writing to remind us all not to
permit ourselves to be involved in conversation, however well-
intended, during assembly.

This is motivated by the fact that I discovered that the wing root
tape IS sufficient to hold the right wing onto a Ventus when the main
spar pin is not fully engaged. This discovery was sufficiently
humiliating that I have waited for a few days to confess.

The hookups of the Ventus are brain-dead simple and foolproof, except
that the locking pins really do need to be engaged.

Sometimes I have forgotten to pull off the wing-root tape before
trying to remove the wings during disassembly, which has sparked one
of those random fantastical thoughts, "I wonder if the main spar pin
is really needed."

I normally assemble completely alone; one day last week a friend came
along to see the glider and wanted to 'help' assemble, and of course
happens to be one of those wonderfully friendly, fascinating, chatty
types.

During the latter part of the subsequent 2-hour flight, I heard a
faint low rumble from behind, making me wonder if the engine
compartment doors had fully closed.

After I landed, I discovered that the tape over the right wing root
gap was still fully covering the gap, but the gap had widened from the
usual 2mm to about 5 mm. I need hardly tell you the sense of fright
and self-abasement this inspired.

I immediately realized that I had failed to push the main spar pin
'home' - normally the sequence is to put it halfway through (into the
left spar) to hold the left wing in place while the right wing is
installed, then go straightaway and push it home. In this case an
interruption to correct wing-taping being done by my 'assistant'
caused this step to be skipped.

I recall an old suggestion that pilots should wear a red cap as a
signal not to be interrupted. But the signal won't be obeyed until
it's learned. Maybe a more effective device would be to screen-print
words on the front and back of a light vest to be worn during
assembly, perhaps
"DEAF" - or
"Shut up (please)"

But of course the real discipline is with us assemblers, to not permit
interruptions, and to say to the first person who offers to help,
"Yes, you can help by preventing anyone from talking to me until this
is done."

Dan Johnson

Thanks for sharing this Dan.

I love your simple answer to the eager helpers.... "you can help by
preventing anyone from talking to me until this is done." After a
while the eager helpers will get the idea.

Curt Lewis - 95

We had a very talkative visitor show up at our club the other day, who
approached one pilot in the middle of
assembling his plane. The pilot just turned to the fellow and said,
"I am doing things that my life depends on
me doing correctly. I'll talk to you later."

Addition to safety concerns is "rash". My last glider fuselage
received an ugly scratch when a veteran glider pilot insisted on
getting my attention to tell me "you should have been here yesterday".
I ignored him, but he kept repeating himself, so I rolled the wing
back into the trailer to wait him out, dragging the wing cradle bolt
along the fuselage as I did so. I was not pleased.

On May 22, 2:16*pm, JJ Sinclair wrote:
Dan,
Thanks for posting that, but the truth is, interuptions WILL occur.
Suppose someone crashed right in front of you while you were
assembling? Don't tell me you won't be interupted. The answer lies in
a final critical assembly check which includes not only the flight
controls but the main wing pins and TE probe. BTW, your Ventus wing
won't stay on with just wing tape, that pin forms the second member
and must have been into the second spar far enough to take the flight
loads. You're one lucky guy!

JJ, who has twice failed to connect the outboard ailerons on an ASH-25
because I was explaining how I never forget to hook everything up to
an on-looker! *But, I caught it both times when I did my critical
assembly check.

JJ beat me to posting this.
I am a huge fan of Critical Assembly Check Lists.

I strongly recommend having one printed on front of your Seat Pan.
Then make a habit of checking it before you get in the glider.
If you have an access door for your controls, have one printed on the
inside of the door and never install the door without going through
the checklist.

Look at your glider and figure out where you should have Critical
Assembly Checklists that you can easily use. I like having them
attached or printed on parts of the glider so I don't have to look for
them.

My HP16 has a Turtle Deck. I have one printed on the Wing Spar. I
never install the Turtle deck without going through the check list
which is, Ailerons Safeties installed, Wing Pin Safeties installed,
Battery Secured.

Keep the checklist to short containing only critical items. The check
list is more likely to be used this way and there less chance you will
skip something on it.

Brian
CFIIG/ASEL

On May 22, 10:38 pm, Brian wrote:
On May 22, 2:16 pm, JJ Sinclair wrote:

Dan,
Thanks for posting that, but the truth is, interuptions WILL occur.
Suppose someone crashed right in front of you while you were
assembling? Don't tell me you won't be interupted. The answer lies in
a final critical assembly check which includes not only the flight
controls but the main wing pins and TE probe. BTW, your Ventus wing
won't stay on with just wing tape, that pin forms the second member
and must have been into the second spar far enough to take the flight
loads. You're one lucky guy!

JJ, who has twice failed to connect the outboard ailerons on an ASH-25
because I was explaining how I never forget to hook everything up to
an on-looker! But, I caught it both times when I did my critical
assembly check.

JJ beat me to posting this.
I am a huge fan of Critical Assembly Check Lists.

I strongly recommend having one printed on front of your Seat Pan.
Then make a habit of checking it before you get in the glider.
If you have an access door for your controls, have one printed on the
inside of the door and never install the door without going through
the checklist.

Look at your glider and figure out where you should have Critical
Assembly Checklists that you can easily use. I like having them
attached or printed on parts of the glider so I don't have to look for
them.

My HP16 has a Turtle Deck. I have one printed on the Wing Spar. I
never install the Turtle deck without going through the check list
which is, Ailerons Safeties installed, Wing Pin Safeties installed,
Battery Secured.

Keep the checklist to short containing only critical items. The check
list is more likely to be used this way and there less chance you will
skip something on it.

Brian
CFIIG/ASEL

I made what I call a "Fast-Five" list for my critical checkpoints on
my ship.
1. Main Spar pin safety
2. Aileron L safety
3. Aileron R safety
4. Elevator Pin safety
5. Elevator rod safety

I also keep a detailed assy checklist that help me remember items such
as the cell phone and to leave my car keys. But the critical list is
used at least twice in assy and in preflight. After all that I still
managed to fly with disconnected instruments once last season...

/Adam

fbrahic wrote:
What about encouraging pilots doing assembly to wear brightly colored
ear muffs or ear plugs to both discourage interactions and remove
distractions?

Pink and furry. You'll be left alone ;-)

Dan, thanks for posting. Glad the tape was enough-this time!
BTW if you fly a Ventus b, assembly can go wrong. The flap drive can go
together setting the right and left flaps at different positions. I
caught this once during assembly, my partner caught it during a control
check. Not sure if the V2 has the same connection.


Shawn

Uh, that is scary... I've wondered several times while helping to put
together Schempp-Hirth planes, why the heck they've done the wing assembly
the way the have - right, it's easy to do it that way, the wings just sit
there when put into the body, but some day someone would forget the main
spar pin... I think it would be a good idea to always (well, only when the
wings aren't mounted!) let the main spar pin rest on the plane's pilot seat
(back seat on two-seater isn't good enough if it's flown by one person.

A couple of days ago, the danish news paper Politiken brought this very
relevant cartoon: http://politiken.dk/wm/article508875.ece - the text says:
"Erik, I told you to get those wings checked before we went on vacation".


Best regards,

Morten Wartou

"danlj" skrev i meddelelsen
...
Dear List,

From time to time a pilot is broken or totalled because assembly was
in some way incomplete. I'm simply writing to remind us all not to
permit ourselves to be involved in conversation, however well-
intended, during assembly.

This is motivated by the fact that I discovered that the wing root
tape IS sufficient to hold the right wing onto a Ventus when the main
spar pin is not fully engaged. This discovery was sufficiently
humiliating that I have waited for a few days to confess.

The hookups of the Ventus are brain-dead simple and foolproof, except
that the locking pins really do need to be engaged.

Sometimes I have forgotten to pull off the wing-root tape before
trying to remove the wings during disassembly, which has sparked one
of those random fantastical thoughts, "I wonder if the main spar pin
is really needed."

I normally assemble completely alone; one day last week a friend came
along to see the glider and wanted to 'help' assemble, and of course
happens to be one of those wonderfully friendly, fascinating, chatty
types.

During the latter part of the subsequent 2-hour flight, I heard a
faint low rumble from behind, making me wonder if the engine
compartment doors had fully closed.

After I landed, I discovered that the tape over the right wing root
gap was still fully covering the gap, but the gap had widened from the
usual 2mm to about 5 mm. I need hardly tell you the sense of fright
and self-abasement this inspired.

I immediately realized that I had failed to push the main spar pin
'home' - normally the sequence is to put it halfway through (into the
left spar) to hold the left wing in place while the right wing is
installed, then go straightaway and push it home. In this case an
interruption to correct wing-taping being done by my 'assistant'
caused this step to be skipped.

I recall an old suggestion that pilots should wear a red cap as a
signal not to be interrupted. But the signal won't be obeyed until
it's learned. Maybe a more effective device would be to screen-print
words on the front and back of a light vest to be worn during
assembly, perhaps
"DEAF" - or
"Shut up (please)"

But of course the real discipline is with us assemblers, to not permit
interruptions, and to say to the first person who offers to help,
"Yes, you can help by preventing anyone from talking to me until this
is done."

Dan Johnson

The Schempp-Hirth pin does not carry any load, it's just there to lock the
assembly.

Very frightening report - thanks Dan!

Bert

"JJ Sinclair" wrote in message
...
Dan,
Thanks for posting that, but the truth is, interuptions WILL occur.
Suppose someone crashed right in front of you while you were
assembling? Don't tell me you won't be interupted. The answer lies in
a final critical assembly check which includes not only the flight
controls but the main wing pins and TE probe. BTW, your Ventus wing
won't stay on with just wing tape, that pin forms the second member
and must have been into the second spar far enough to take the flight
loads. You're one lucky guy!

JJ, who has twice failed to connect the outboard ailerons on an ASH-25
because I was explaining how I never forget to hook everything up to
an on-looker! But, I caught it both times when I did my critical
assembly check.

The Schempp-Hirth pin does not carry any load, it's just there to lock the
assembly.

Yeah, your right, I was thinking of the Nimbus pin which does carry a
load.

Dan, doesn't your proceduer of putting the pin half way, build in an
interruption? Why not get the wings together (prying with a broom
stick inserted in the hole) and then put the pin in all the way and
safety it right then? When I am interrupted, I try and leave something
there to remind me that I haven't finished the procedure, like hanging
my hat on the TE probe to remind me to go back and finish the tail
plane installation. I remember a guy that was right there, but
couldn't secure the tail plane because he had given the little red
tool to his wife so she could put water in the
wings................................he never came back to finish the
job and he is no longer with us!
Thanks for posting, we need to talk about these kind of things,
JJ

JJ Sinclair wrote:
The Schempp-Hirth pin does not carry any load, it's just there to lock the
assembly.

Yeah, your right, I was thinking of the Nimbus pin which does carry a
load.

Dan, doesn't your proceduer of putting the pin half way, build in an
interruption?

My Discus manual recommends you do it this way -- halfway in to hold the
first wing, then all the way after the second wing is mounted.

I wonder if there is a way to have a little red flag that hangs over the
ASI when the wings are off. It would have velcro on it, and you would
stick it to another piece of velcro on the wing pin when the pin is
fully installed.


Why not get the wings together (prying with a broom
stick inserted in the hole) and then put the pin in all the way and
safety it right then? When I am interrupted, I try and leave something
there to remind me that I haven't finished the procedure, like hanging
my hat on the TE probe to remind me to go back and finish the tail
plane installation. I remember a guy that was right there, but
couldn't secure the tail plane because he had given the little red
tool to his wife so she could put water in the
wings................................he never came back to finish the
job and he is no longer with us!
Thanks for posting, we need to talk about these kind of things,
JJ