Chapter 1. INTRODUCTION - TM-9-6685-202-140004

TM 9-6685-202-14

CHAPTER I

INTRODUCTION

Section I. GENERAL

1-1. Scope

1-3. Maintenance Technique

a. This manual contains instructions for the

a. The IROAN (Inspection and Repair Only as

operation and maintenance of the Mercurial Altitude

Necessary) maintenance technique will be used to

Test Barometer Type A-1, 6685-511-9864 and the

restore this materiel to a serviceable condition.

Metric Mercurial Barometer Type A-1 Modified, 6660-

1827792. The barometers are utilized to supply the

b. The IROAN maintenance technique is the

measurement accuracies required to support pertinent

systematic isolation and remedy of a malfunctioning or

Army materiel and to calibrate other mercurial or

defective c o m p o n n t through test, diagnosis, and

aneroid barometers of the same or lesser accuracy.

repair. No component of the materiel is disassembled

The manual also contains the description and theory of

before a definite requirement for disassembly has been

operation as well as information on the operation and

established.

maintenance of associated equipment.

b. Appendix A contains a list of current references,

1-4. Differences Among Models

including supply catalogs, technical manuals, and other

related publications applicable to the barometer.

a. The type A-1 mercurial altitude test barometer is

manufactured by the Bass Instrument Corporation,

c. Appendix B contains the maintenance allocation

Washington, D. C. Barometers, serial numbers 6 to

chart.

It specifies the level of responsibilities of

248, were manufactured in accordance with USAF

maintenance with regard to the service and repair to be

Specification Number 27022. Serial numbers 276 to

performed on the barometers.

836 were manufactured in accordance with MIL-B-4308

d. Appendix C contains the basic issue items list

specification. Serial number 1100 and subsequent were

which lists items furnished with the barometer, and a list

manufactured in accordance with MIL-B-4308B

of repair parts that are normally required to repair and

specification.

maintain the barometer.

b. The manufacturer's part number is 10-00-00-F

1-2. Maintenance Allocation

for the latest model described in this manual. However,

there are older models currently in use with different

measurement capabilities. The barometers with part

a. The authorized maintenance responsibilities will

numbers 10-00-00-A and -D are designed to be correct

be limited to those functions prescribed by the

at 0 (32 ) and 980.665 cm/sec 2 Barometers with

maintenance allocation chart (MAC). When the nature

part number 10-00-00-F are designed to indicate

of repairs, modifications or adjustments is beyond the

correctly at 25 (77 ) and 980.665 cm/sec . Serial

scope or facilities of the using personnel, the

numbers 10 through 46 are designated as model A,

responsible maintenance or repair unit will be informed

while models B, C, and E do not conform to any

in order that trained, qualified personnel with proper

particular serial numbering sequence. Serial numbers

tools and equipment can perform the necessary

47 through 402 are classified as model D, while serial

functions.

numbers 450 through 1099 are classified as model F.

b. Some repair parts are available to support this

materiel in the Army supply system. Procurement of

repair parts will be accomplished in accordance with TM

9-4931-700-34P-1, Direct Support and General Support

Maintenance Repair Parts and Special Tools List for

Calibration Standards Sets.

1-1