The large increases in the speed and volume
train operates a counter-drum assembly and a
pointer assembly that traverses the instrument
of air traffic caused the need for a more efficient,
dial. The counter/drum provides a numerical
automated air traffic control system. The
ATCRBS, which automatically provides the
readout of altitude. The position of the pointer
provides greater accuracy of readout.
controller with a three-dimensional identified
presentation, is a step toward the solution
The baroset knob is coupled, via a barometric
of the problems of vertical separation, terrain
setting shaft, to two spur gears that run on an idler
clearance, and collision avoidance. Automatic
altitude reporting relieves both the pilot and
shaft. One spur gear meshes with a gear that drives
the barometric counter. The other spur gear
the ground controller of much radio work.
meshes with the gear train mechanism that
It also provides continuous monitoring of the
provides altitude indication. Thus, the pressure
altitude of properly equipped aircraft. This
system results in increased efficiency in the air
the barometric counter shows is tied to a particular
indication of altitude.
traffic control system. The system also gives pilots
a more accurate altimetry system, reducing
To permit calibration of the pressure and
altimetry errors of 0.8 percent of altitude to 0.35
altitude relationship, a device can disengage the
percent of altitude.
normal barometric operation of the altimeter.
Using a locking screw, you lock the device in the
locked position. In this position, both spur gears
ANGLE-OF-ATTACK (AOA)
on the idler shaft are actuated by the baroset
INDICATING SYSTEM
knob. When calibrating, slacken the locking screw
and move it toward the edge of the bezel. You
The angle-of-attack indicating system detects
can now withdraw the baroset knob by a small
aircraft angle of attack from a point on the
amount away from the bezel. This action
side of the fuselage. It furnishes reference
disengages the knob from one spur gear so
information for the control and actuation
turning the knob now operates only the altitude
of other units and aircraft systems. It provides
indication.
signals to operate an angle-of-attack indicator
Figure 6-27.-Altimeter block diagram.
