how they process input data and distribute output
pitot-static system to sense false pressures. The
data to the various systems using the data. Data
system then supplies erroneous information to the
requirements vary with the type and mission of
flight instruments. The altimeter, for instance,
the aircraft.
may show an error of more than 3,000 feet. A
3,000-foot error in altitude is intolerable and
The F-14 CADC system contains a single-
could put an aircraft in an extremely dangerous
processor digital computer with a separate
position.
independent analog backup wing sweep channel.
The CADC can make yes and no decisions and
The system that compensates for altitude and
solve mathematical problems. It converts outputs
other pitot-static errors is the air data computer
to either digital or analog form, depending on
system (ADC system). Many variations exist in
which aircraft system is to use the information.
both the name of the systems and the method of
The CADC gathers, stores, and processes signals
data development. The system in the F-14 is
representing pitot pressure, static pressure, total
strictly a digital computer known as the central
temperature, and angle-of-attack data derived
air data computer (CADC). The system in the S-3
from the aircraft airstream sensors.
is an airspeed altitude computer set (AACS). The
AACS is a digital computer, but it is very different
Figure 6-13 shows the functional relationship
from the CADC used in the F-14.
between the CADC (digital processor), its inputs,
and the various functions in each aircraft system
using the data. The digital processor performs
Purpose
wing-sweep, glove-vane, and flap-and-slat
schedule computations. It also performs limit-
Many inputs are common to the various types
control and electrical interlocks, failure detection,
of ADC systems. Air data computers differ in
Figure 6-13.-F-14 air data computer system.
