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C00002 00002	COMPUTER CONTROLLED AIRPLANES
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COMPUTER CONTROLLED AIRPLANES

1. Introduction
	Computers are already used in a  number of military airplanes
and  are projected  for the  supersonic transport.   This  article is
concerned with the use of computers in present planes  even including
light planes.  We envisage a  small real time computer no larger than
a  PDP-8I carrying  out tasks in  the areas  of navigation, collision
avoidance and responding to traffic control, monitoring the condition
of  the airplane, optimizing  flight path  taking into  account fuel,
load, weather, and traffic.

2. Navigation
	We advocate no basically  new electronic navigation  systems.
The basic system we consider is the familiar omnirange.  However, the
computer  will switch  its radios  at .1  second intervals  among all
available omnis and will compute each few seconds a best  estimate of
the  current  position  of  the  aircraft.   This  estimate  will  be
displayed  for the pilot on a map on  a CRT and will be available for
interrogation from  the ground  or  other airplanes.   More  accurate
positions should be available  than at present because any systematic
inaccuracies in the radials of an omni due to terrain can be  allowed
for by  the  computer; a  correction equation  for the  omni will  be
stored  along with  its position  in the  computer equivalent  of the
sectional chart.  Our goal  is that navigation be accurate enough  so
that aircraft can  be flown close enough together so  that there will
be enough airspace for everybody without danger of collision.

	All instruments now available to the crew will be read by the
computer  at appropriate  intervals,  e.g.  every .1  to  10  seconds
depending on  the instrument. In navigation,  altitude, airspeed, and
heading information will be integrated with the information  obtained
from the omnis.  The amount of  information available is much greater
than is required to monitor position, and any inconsistencies will be
detected and the offending instrument reported to the crew.

3. Collision avoidance and traffic control
	Here again we want a system with large redundancy. The basisc
scheme is  that the  air traffic  control computer  interrogates each
airplane  every  few seconds  and  gets its  position  information or
perhaps even  the raw  bearing information received  from the  omnis.
Since  the interrogation  is  electronic, a  single  25kc band  could
interrogate 100 airplanes per second  at 250 bits per  interrogation.
Each airplane can  be given relevant traffic information  or specific
collision avoidance instructions if this is desired.

	In addition  to the standard  information transmitted  to the
airplanes, special messages  addressed to the crew of an airplane can
be presented on the CRT or printed on a strip printer.

	Additional redundancy  can  be  obtained  by  timing  signals
returned from a plane or even  signals transmitted from the ground to
a plane, then to another plane and then to another ground receiver.

4. Monitoring
	The  crew  of an  airplane  is  supposed to  monitor  all the
instruments at regular intervals.  However, this activity can be done
much more  reliably by a computer. Moreover,  the computer can relate
such information as  airspeed, attitude, engine  RPM, fuel flow,  and
air pressure and temperature  and check continuously for fall  off of
engine  performance or  ice buildup.   Other  parameters that  can be
monitored   include   electrical    system   performance    including
availability of  emergency power,  correct functioning  of navigation
and   other   lights,  icing   conditions,   navigation  checkpoints,
maintenance of communication, and all engine instruments.

5. Visual monitoring
	With  the  aid  of television  cameras,  a  computer  can  be
programmed  to  use visual  information.   The  possibilities include
finding airports and runways under visual conditions, landing, taking
off,  and taxiing,  terrain  avoidance, and  collision avoidance.  In
short, the  computer can potentially perform the full range of chores
of the VFR pilot.   All this, however, places much larger  demands on
the computer  and the programming than the  previous applications and
is therefore somewhat further in the future.