Section V. OPERATION UNDER UNUSUAL CONDITIONS

TM 9-1270-212-14&P

When firing a 40-mm, 20-mm or 7.62-mm

Do not engage the TSU left hand grip ACTION

weapon, keep the sight on the target and the

switch during any switching action on the

ACTION switch closed after trigger release

armament control panels.

until the gun stops firing.

h. Press the TRIGGER switch. The turret continues to

d. Electrically bypass the TSU by setting the MODE

follow the sight, firing as desired, until one of the turret

SELECT switch on the TOW control panel to OFF or by

limits is reached (110 degrees in azimuth; +18 degrees, -60

setting the ACQ TRK STOW switch (fig. 2-5) to STOW.

degrees in elevation). At that point, the gun will cease to

fire and the reticle will begin to flash, indicating an

e. Insure that the MASTER ARM switch is set to ARM.

out-of-coincidence condition.

f. Hold the sight steady on target.

i. Set the MASTER ARM switch on the pilot arma-

g. Press the ACTION switch on the TSU left hand grip

ment control panel to STBY or to OFF and the INV (or

ALTNR) and BAT (or BATTERY) switches to OFF.

(fig. 2-3). The turret follows the sight.

Section V. OPERATION UNDER UNUSUAL CONDITIONS

Condensation or freezing moisture on the optical sights can

2-14. General.

obstruct vision and interfere with proper use of the

instruments.

The only precautions necessary when operating the HSS

under unusual environmental conditions pertain to

b. Operation in Sand or Dust. When operating in sand

operating in extreme cold or in sand or dust.

or dust, clean the linkage rails frequently with a clean cloth

and alcohol or other solvent that will not leave a residue. If

2-15. Operation Under Unusual Conditions.

the linkage arm assembly becomes hard to operate along

the rails, the linkage assembly may require replacement. See

a. Operation in Extreme Cold. When operating in

Chapter 5, paragraphs 5-13 through 5-19, for removal and

extreme cold, avoid breathing on the optical sights.

installation instructions.