C H A P T E R 1
I N T R O D U C T I O N
Section I. INTRODUCTION
General. This handbook contains operation, 1-2.
The army equipment
maintenance, and overhaul instructions, illustrated
and record system and procedures established in TM
parts breakdown, and repair parts list for Pitot and
38-750 apply to this equipment. The applicable forms
Static Systems Tester (fig. 1-1), Part Number:
required by TM 38-750 shall be used.
S621312, hereafter referred to as the Test Set.
Section II. DESCRIPTION AND DATA
Purpose of Equipment. The test set is a
portable, self-contained field instrument which is used
for checking the performance characteristics of vacuum
and pressure aircraft instruments, pitot and static sys-
tems, and as a primary vacuum and pressure source for
operation of aircraft computer system. The test set ac-
curately simulates the engine vacuums and pressures
and atmospheric pressures which are present during
normal operation of the aircraft. A small highspeed
pump in the test set produces a vacuum 29 inches of
mercury and pressures in the range of O to 25 psi (man-
ifold pressure gauge) (5, fig. l-l).
Description of Equipment. The test set is
17-5/8 inches long, 15-1/2 inches deep and 19 inches
high when contained within its removable cover for
transit. The cover contains accessories necessary for
proper operation of the test set. When the cover is re-
moved, all operating controls and indicators and acces-
sories are accessible for immediate use.
a. The instrument panel contains three aircraft
instruments; Rate-of-Climb (Fig 1-1 item 1), Altimeter
(item 2), Airspeed Indicator (item 4). Fuel Pressure In-
dicator (item 6) and Manifold Pressure Indicator (item
5) are no longer required in testing aircraft compo-
nents. Remove indicators, cap off airlines, stow electri-
cal connectors and install cover plates over existing
b. The rear panel contains four fittings: Fuel
Pressure, Manifold Pressure, Air-Speed and Rate-of-
Climb Altimeter. During operation, the instrument
under test is connected to the applicable fitting. The
rear panel also contains the Power connector to which
ac or dc operating power is applied through an appro-
priate cable assembly.
c. At the top of the test set is a hinged panel (3)
which contains a table which lists the most current cal-
ibrationcorrections for the five master instruments on
the test set instrument panel. When its captive fasten
ers are released and the panel is raised, five small
OPEN-CLOSED selector valves become accessible
These valves, designated Rate of Climb, Altimeter, Air
Speed, Manifold Pressure to the appropriate instru-
ment panel are for the external instruments to be
d. For access to interior components of test set,
captive fasteners on the instrument panel, are released
and the panel is swung upward, With the panel open,
the motor-pump assembly reservoir and electrical
power supply components are easily visible. In addi-
tion, the lower front panel and rear panel can be re-
moved for access to the motor-pump assembly rese-
voir, pressure lines, and bellows block assembly. The
right side contains a window (9) to permit observation
of fluid level in the reservoir and a removable cover
plate (8) which permits an access to the reservoir
drain/fill and run valve and hose.
The test set contains
two power cables and two cable adapters to permit op-
eration from the following power sources:
a. 28 +4, -6 volts dc.
b. 115 volts ac+ 10 percent, 50 to 500 cycles, sin-
c. 115 volts ac + 1 percent, 50 to 500 cycles, three-
plied with the ttst set are listed in Table 1-1.