components in the cabin, pressure suit, and
VERSATILE AVIONICS SHOP TEST
equipment air-conditioning systems. To accom-
(VAST) EQUIPMENT
plish checkout of these systems, apply external
The VAST system now in use aboard Navy
electrical power to the aircraft.
aircraft carriers can cope with the continually
Checkout of the system under test involves
simulation of sensor and limiter inputs by the test
changing character of avionics testing. VAST will
set. You can connect external test equipment to
significantly reduce the space required by
test points on the test set to measure resistance,
equivalent special and manual support equipment.
voltage, or waveforms to determine system
In its basic form, a VAST station is assembled
operation. You can also determine system opera-
from an inventory of functional building blocks.
tion by visual monitoring. For example, with a
These blocks furnish all the necessary stimuli and
known electrical input into the air-conditioning
measurement capability to check many naval
system, air-conditioning valves should move to
avionics equipments. As new avionics come into
use, test station configurations are modified by
a known position.
adding new building blocks to furnish new
parameters or greater precision to existing
capabilities.
REVIEW SUBSET NUMBER 10
A typical VAST station consists of a computer
subsystem, a data transfer unit (DTU), and a
Q1. What test set is used to test pitot-static
stimulus and measurement section. The stimulus
systems?
and measurement section contains functional
building blocks configured to meet the intended
test application. Figure 2-40 shows a typical
carrier-based VAST station.
Q2. Name the two measurements you can take
The carrier-based test station is controlled by
with the TF-20 test set.
a computer subsystem that executes test programs
to assure accurate and satisfactory testing. The
computer subsystem includes a general-purpose
digital computer, which not only executes test
Q3. The AN/PSM-17A test set is used to test
routines but also provides diagnostic and com-
what system?
putational capabilities. It also processes data and
Figure 2-40.-VAST station.
