Light panels on airliners

From: (Robert Dorsett)
Organization: Capital Area Central Texas UNIX Society, Austin, Tx
Date:         27 May 93 11:23:27 PDT
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For many, many years I've wondered how the cockpit panel lighting in 
airliners worked.  It's *high quality* stuff, completely uniform, near-
perfect lettering, no mistakes, is cold-like-metal, etc.

Tonight, I learned how.

1.  The cockpit panels are made of PLASTIC, not metal.   Metallic
    gray paint is used on the front.
2.  The lettering is etched in the panel from reverse.
3.  The paint is laid on thick from the front; the letters are preserved
    through a silk-screening process (not clear how).
4.  A lighting panel, containing imbedded light bulbs, is applied to the
    back of the front panel; it's comprised of transluscent plastic.  It 
    has raised lettering on the front, and "sandwiches" precisely into the 
    front panel.  The lighting panel is about a quarter-inch thick.
5.  On most airplanes, the lighting panel is attached to the front panel;
    thus, if an element burns out or needs replacing, it has to be sent
    back to the manufacturer.
6.  The connector for the lighting panel is about a third of an inch in radius,
    and can be found by looking for a very small "X" on the panel.  

Oh, well, news to me. :-)

Robert Dorsett!!rdd