Use heater probes designed for
use on the engine thermocouples
gradients are very critical in the
design of heater probes. Each
type of aircraft thermocouple has
its own specially designed probe.
Never attempt to modify heater
probes to test other types of
assemblies in the tailpipe during
Never allow the heater probes to
will result in damage to the jetcal
(5) Maintenance. Apply a few drops of oil to
hinges, then wipe off excess oil with clean cloth. With
wheels removed, apply a light coating of grease to
wheel mount axles.
Maintenance. General maintenance procedures for
instruments and instrument systems are covered in the
following paragraphs. General precautions are as
Instruments are delicate devices
and will always be handled very
Always replace instruments with
another of like kind and type, or a
suitable substitute as listed in
appendixes and special tool lists.
Configuration of aircraft (location
and positioning of instruments or
components) will not be altered
unless authorized by AVSCOM.
Never exceed pressures or values
specified in publications dealing
with test procedures for that
Thread compound will be used on
all threaded coupling connectors
compound shall be applied so that
entrance into gauge is prohibited
(i.e., apply a light coating to two
threads of male end, starting at
adjustable wrenches will not be
used on coupling connectors.
a. Inspection of Instrument Systems. Instrument
systems will be inspected and functionally checked in
the aircraft. However, indicators or transmitters may be
removed from the aircraft and bench checked whenever
b. Inspection Requirements. Use the following
paragraphs to inspect instruments.
(1) Range markings. Instruments must be
range-marked in accordance with applicable operator
manual and TM 55-1500-345-23.
(2) Mounting. Shock-mounted instrument
panels will be free to move in all directions with a
minimum clearance of 1/4 inch between panel and its
supporting structures. When panel does not have
specified clearance, inspect rubber shock mounts for
looseness, cracks, or deterioration. Loose mountings
will be tightened, and cracked or deteriorated mountings
will be replaced.
(3) Connecting lines. Wiring or flexible
tubing behind instrument panel will be sufficiently long
to permit easy connection to indicators (a minimum of 4
inches in front of panel). All electrical wiring will be
anchored to prevent swinging or sagging, but must not
connection threadings and all line
connection threadings to be sure
they are the same thread. Do not
force under any circumstances.
(4) Operation of instruments. Instruments
must operate satisfactorily as required by applicable
operator manuals. Instruments that do not operate
satisfactorily will be replaced.
(5) Physical defects. Instruments with
physical defects or damage must be replaced.
(6) Corrosion. Replace instrument if
corrosion damage is present.
(7) Color coding. The Army uses two types
of identification systems to color code the plumbing
lines and electrical conduits of aircraft. The two
systems used are the printed-symbolized tape system,