Section I. INTRODUCTION AND DESCRIPTION

TM 55-4920-416-13

NAVAER 17-15C-539

Section I

Paragraphs 1-1 to 1-7

SECTION I

INTRODUCTION AND DESCRIPTION

1-1. GENERAL.

selector valves, one for vacuum and one for pressure tests;

four micrometer needle valves used for fine or vernier control

1-2. This handbook contains operation, maintenance and

of vacuum and pressure; a power switch for the pump motor,

service instructions for Vacuum-Pressure Test Set VPT-7A

along with an indicator lamp and fuses. At the rear of the test

(see figure 1-1) manufactured by Intercontinental Dynamics

set are four self-sealing quick-couplings for connecting test air

Corporation, Englewood, New Jersey.

lines and a multi-terminal AN receptacle for electrical

connections. Along the top of the instrument are a row of

1-3. PURPOSE OF EQUIPMENT.

cards which give the latest calibration corrections for the

master instruments on the test set panel. Under this row of

1-4. Vacuum-Pressure Test Set VPT-7A is a portable, self-

cards, accessible by lifting the narrow aluminum cover, are five

contained pressure and vacuum test set whose primary

small selector valves used for self-checking of the test set

function is the testing of aircraft instruments such as altimeters,

master instruments during calibration and recalibration of these

rate-of climb indicators, airspeed indicators, manifold pressure

instruments. For convenient access to components of the test

gauges and fuel pressure gauges. In the performance of this

set, the main panel is hinged at the top and may be opened by

function, the test set accurately simulates engine or

turning the five Dzus fasteners accessible from the front.

atmospheric pressures and vacuums such as are met in the

When the main panel is opened the motor pump assembly, air-

normal operation of an aircraft. Simulation of these pressures

oil reservoir, and the electrical power supply components are

and vacuums is accomplished by means of a small high speed

visible. In addition, the side doors and the lower front panel

pump capable of producing pressures up to 50 pounds per

are hinged and secured with Dzus fasteners. These doors

square inch and a vacuum equivalent of an altitude of 80,000

provide access to the reservoir, with its drain refill valve and

feet or more. Accessories which will operate in conjunction

hose, and the filter sumps in the vacuum and pressure

with this test set will be available in the future for testing Mach

systems. The lower front panel provides access to the three

indicators.

vacuum and three pressure safety relief valves. The test set is

designed to operate from either a 28 V dc or 115 V ac source.

1-5. DESCRIPTION.

The line frequency of the 115 V ac source may be from 50 to

500 cycles.

1-6. The overall size of the VPT-7A is 16-1/2 inches wide by

14-1/32 inches deep by 14-3/4 inches high. This includes a

1-7. ACCESSORIES SUPPLIED WITH TEST SET. The

removable cover which contains all the accessories and tools

operating accessories supplied with the VPT-7A Vacuum-

necessary for proper operation of the test set. With the cover

Pressure Test Set are illustrated in figure 1-2, and listed in

removed, all of the major operating components of the test set

Table 1-1 by part number, quantity, nomenclature and use.

are visible.

These consist of five aircraft instruments

representative of the types to be tested: two multiple function

TABLE 1-1

ACCESSORIES ASSEMBLY (IDC #10471) (For net higher assembly, see figure 9-1)

Figure 1-2

Part No.

Qty

Nomenclature

Use

Index No.

10494

Clamp Assembly, Pitot Static, Round (ICDM)

Pitot System Tests

10493

Clamp Assembly, Pitot Static, Oblong (ICDM)

Pitot System Tests

10487-1

Sleeve Assembly, Pitot Pressure, Round (ICDM)

Pitot System Tests