Screw the splices!
Splices are notorious for piles of circular references and harness
flattening problems.
At the top level assembly, the circular references in our cables were
causing loops and
failures that caused the top assembly to take up to 6 hours to open.
There were many cables whose circular references were killed easily...
They had no splices.
There was one monster cable with multiple splices. It had 29 circular
references as well.
Because the cable was so difficult to flatten it became a sacred cow. No
one was ever
permitted to tweek it ever again! I started killing circular references
in the top assy,
there were over 120 of them... although there were only 67 being
reported. When I was done,
there were(any guesses?) 29 of them... all in that one cable. I created
a simplified rep
for top level assembly drawings that did not have that cable in it. Now
the top level
assembly opens in 20 minutes...
When I am routing a cable with splices, I attempt to keep the splices in
the backshells.
(good practice, they are easily checked and serviced that way)Also, I
only route to the
backshell itself. It's like magic - No splices to route ever! Some cases
do not allow
The splice to occur inside the backshell. These I fudge! Either route
different gauge wires
To the same location for purposes of calling out a splice, or just
continue routing to the
backshell if cable diameter is not an issue. If you really really really
want a visible
Splice on your drawing, you can always add a "label" feature and call it
a splice...
As long as your drawing and resulting cables are accurate, I am willing
to let my best
modelling practices slip a tad. This is especially true if you have any
concern over
maintaining your top level assembly... If you get enough splices, and
enough circular
References, your top assembly won't even open anymore, it will just loop
for an hour then crash.
Weighing risk to benefit... DEATH TO ALL SPLICES!!!
Everybody's gotta vent every once in a while...
Frederick Burke
Avionics Installations Engineer
Fire Scout VTUAV - Unmanned Systems
Northrop Grumman Corporation
858-618-7163
858-618-7186 (FAX)
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