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Sender: "Team Ada: Ada Advocacy Issues (83 & 95)" <[log in to unmask]>
Date: Tue, 28 Jul 1998 07:09:35 -0400
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Reply-To: "Marc A. Criley" <[log in to unmask]>
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From: "Marc A. Criley" <[log in to unmask]>
Organization: Lockheed Martin M&DS
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Matthew S. Whiting wrote:
> Stanley Allen wrote:
> >
> > Matthew S. Whiting wrote:
> > >
> > > It seems a little melodramatic to me to consider a flight SIMULATOR to
> > > be a safety critical application.  Now a flight CONTROL system in a real
> > > airplane is another matter...
> > >
> >
> > If you are thinking along the lines of "Microsoft Flight Simulator",
> > you are correct.  However, many simulation facilities for pilot
> > *certification* training involve a lot of large moving parts.  These
> > are the "motion-based" training simulators which often have a cockpit
> > elevated using hydraulic stilts and which allow multiple degrees of
> > motion.  In addition to simple take-off and landing motions (BTW,
> > I say "simple" knowing that the safety aspects of these activities
> > are not trivial), such a training device may often be programmable
> > via instructor inputs to simulate motion resulting from strong winds,
> > ascents and descents, and "battle" action.  For these kinds of
> > simulators, life- or limb-threatening hazards are not unknown.
> No, definitely not MS Flight Sim!  I'm a pilot myself and have a little
> familiarity with full-motion flight simulators from some training I took
> at Flight Safety.  Sure if one went haywire it could shake you up a bit,
> but I think most flight sims have an E-stop button in case things go
> nuts.  I design industrial process control systems and we have several
> E-stop buttons near almost any station that a human might occupy.  It is
> very hard to E-stop a flying airplane, an ATC computer, a pacemaker,
> etc.  I prefer to use "safety critical" for those situations where it
> really fits almost all of the time, rather than a situation where it may
> fit under some very unusual circumstances.
> Granted it is a fairly minor semantic point, but if we get too casual
> about the term "safety critical" it will soon lose its meaning.  You can
> cry "wolf" only so many times...
> Matt

As a former employee of a full-motion flight simulation company, I can
assure you that high-fidelity simulators, especially military ones, can
do more than "shake you up a bit".  The Army officer in charge of the
program office for one helicopter simulator program wanted that thing to
_kick_ when it got hit by a simulated round, enough to convince the pilot
he or she really doesn't want to experience the real thing.  There have
been bruises, sprains, even broken bones when someone wasn't buckled in,
since they were only in a flight "simulator".  There are also instances
where the motion system froze at its full vertical extension, leaving the
cockpit as much as forty feet off the floor, and cases where the whole
thing started leaning until it resembled the Leaning Tower of Pisa...and
then froze.

Ada observation:  The B2 flight simulator runs on about a million lines of
Ada, with another million in tools and systems that support development of
the real-time software.

Marc A. Criley
Chief Software Architect
Lockheed Martin ATWCS
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Phone: (610) 354-7861
Fax  : (610) 354-7308