Odd expression: "screw the pooch" = get things all fouled up

[Gerald Cohen]

Yesterday I watched an episode of "Law on Order" and was surprised to
hear one of the detectives refer to someone who "screwed the pooch",
i.e., got something all fouled up. I had never come across this
expression before but find it on Google, e.g. "screwed the pooch on
Iraqi intelligence."

    Jonathon Green's _Cassell's Dictionary of Slang_ dates it from the
1960's, with a few variants. There doesn't seem much doubt that the
original reference was to bestiality, but how did this extend to "get
things all fouled up"?

    Back to Google: http://www.halfbakery.com/idea/Kitty_20Pager
where someone named "angel" wrote on Aug. 15, 2002:
"A cursory trip through Goooooooogle reveals that it's slang used by
test pilots in the '50's.  To screw the pooch is to be in an aircraft
when it crashes.  More widely, it is to fail in a spectacular manner.
As to etymology, dunno."

    I'll check a glossary of airforce lingo in a few days.  Would
anyone on ads-l have anything to add?

Gerald Cohen