ARMS-D-Request@XX.LCS.MIT.EDU (Moderator) (08/29/86)
Arms-Discussion Digest Friday, August 29, 1986 9:37AM
Volume 7, Issue 9
Today's Topics:
Administrivia
F-16 Problems (from Usenet net.aviation)
different strokes
Duel (sic) phenomenology
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Date: Thu, 28 Aug 1986 09:54 EDT
From: LIN@XX.LCS.MIT.EDU
Subject: Administrivia
Please help with the following messages:
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Message failed for the following:
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Thanks.
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Date: Wednesday, 27 August 1986 15:31-EDT
From: Bill Janssen <janssen at mcc.com>
To: risks at csl.sri.com, arms-d@xx.lcs.mit.edu
Re: F-16 Problems (from Usenet net.aviation)
A friend of mine who works for General Dynamics here in Ft. Worth
wrote some of the code for the F-16, and he is always telling me about
some neato-whiz-bang bug/feature they keep finding in the F-16:
o Since the F-16 is a fly-by-wire aircraft, the computer keeps the pilot from
doing dumb things to himself. So if the pilot jerks hard over on the
joystick, the computer will instruct the flight surfaces to make a nice and
easy 4 or 5 G flip. But the plane can withstand a much higher flip than that.
So when they were 'flying' the F-16 in simulation over the equator, the
computer got confused and instantly flipped the plane over, killing the
pilot [in simulation]. And since it can fly forever upside down, it would
do so until it ran out of fuel.
(The remaining bugs were actually found while flying, rather than in
simulation):
o One of the first things the Air Force test pilots tried on an early F-16
was to tell the computer to raise the landing gear while standing still on
the runway. Guess what happened? Scratch one F-16. (my friend says there
is a new subroutine in the code called 'wait_on_wheels' now...) [weight?]
o The computer system onboard has a weapons management system that will
attempt to keep the plane flying level by dispersing weapons and empty
fuel tanks in a balanced fashion. So if you ask to drop a bomb, the
computer will figure out whether to drop a port or starboard bomb in order
to keep the load even. One of the early problems with that was the fact
that you could flip the plane over and the computer would gladly let you
drop a bomb or fuel tank. It would drop, dent the wing, and then roll off.
There are some really remarkable things about the F-16. And some even more
remarkable things in the new F-16C and D models:
o They are adding two movable vents called 'canards' that will be installed
near the engine intake vent under where the pilot sits. By doing some
fancy things with the flight surfaces and slick programming, they can get
the F-16 to fly almost sideways through the air. Or flat turns (no
banking!). Or fly level with the nose pointed 30 degrees down or up (handy
for firing the guns at the ground or other aircraft).
I figured this stuff can't be too classified, since I heard the almost same
thing from two different people who work at GD. I hope the Feds don't get
too upset...
George Moore (gm@trsvax.UUCP)
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Date: Wed, 27 Aug 1986 23:49 EDT
From: LIN@XX.LCS.MIT.EDU
Subject: different strokes
From: 143B::ESTELL <estell%143b.decnet at nwc-143b.ARPA>
Drucker has argued that profits are the proper return on risk of
doing business; some hold that it follows that aerospace companies
[et al] that take high risks for DOD [et al] SHOULD make megabucks.
By comparison, "non profit" organizations that are federally funded
need only survive, not prosper; thus some argue that the costs CAN
be lower.
This is not a bad idea, but it omits the fact that aerospace
contracting for DoD is NOT generally a high risk proposition. When
contracts are let on a cost-plus basis, the government picks up the
risk. The rare exception is something like th F-20 Tigershark,
developed by Northrop at its own expense. Note that the F-20 hardly
uses risky technologies.
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Date: 28 Aug 86 14:47:54 bst
From: S.WILSON%UK.AC.EDINBURGH@ac.uk
Subject: Duel (sic) phenomenology
From: Volume 7, Issue 6
Clifford Johnson writes...
> Replacing x by the phrase "satellite warning," and y by the
> phrase "radar warning," the above logical computation could read
> if satellite warning or radar warning, then attack warning
> In this context "certain" could correspond to a positive warning
> from a satellite sensor, and "likely" could correspond to "loss of
> signal" from a radar. By such reasoning, dual phenomenology is
> logically less than dual.
Forgive me if I'm missing something, but surely you would expect a logical
AND in the above construction rather than an OR. I wouldn't expect a to
sound a warning of attack if one of my sensors went dead unless the other
one also said there was something happening. In that case there is still
an element of duality in the detection and the warning level stays at
'likely' rather than 'certain'. In real life you would obviously want
something much more complex than this anyway.
Sam Wilson, Edinburgh Regional Computing Centre,
University of Edinburgh, Scotland.
The usual disclaimers apply.
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End of Arms-Discussion Digest
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