[OT] Re: Meaning and origin of term I've heard in a few movies

Nathan spake thusly upon matters weighty: 

> Hello,
> 
> Was watching Event Horizon last night and kept hearing the crew use
the term
> "five by five".  It seemed to indicate that everything is working
fine.  I
> thought that I've also heard the term in another SF movie (Aliens,
maybe?).
> I was wondering if anyone out there could say what the term means
(five by
> five what?) and where it came from.

Pilots landing on Aircraft carriers come in on a virtual 10x10 grid 
to let the air traffic guys and the guys on the deck  know if they 
are low/hi/off left/off right. 5x5 is dead centre on the grid. Now 
when people ask "what's your status?", 5 by 5 is now taken to mean 
all systems a-ok. The Colonial Marine dropship pilot in Aliens uses 
the phrase "In the groove, five by five." to indicate that the 
dropship is on the correct approach vector and everything looks good.

Tom.
 
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