TM 5-4220-225-14
Key
Control or Indicator
Function or Use
1
Air Supply Valve
Control knob regulates the flow of air into the helmet.
2
Exhaust Valve
a. Adjustable configuration: diver can adjust helmet P
from 0.3 psig to 2.0 psig overbottom pressure.
Operating together with the air supply valve allows
diver to control buoyancy while maintaining adequate
ventilation.
b. Ambient configuration: installed when helmet is used
with neckdam. P is fixed at 0.125 psig to prevent
neck squeeze.
3
Chin Button (adjustable configuration)
Permits the diver to manually override the exhaust valve
setting.
4
Locking Device Assemblies
Secures helmet to lower breech ring. Operated by locking
device with safety pins.
SECTION II. OPERATOR PREVENTIVE MAINTENANCE
CHECKS AND SERVICES (PMCS)
Paragraph
Page
2-3
General .....................................................................................................................
2-3
2-4
Purpose of PMCS Table ............................................................................................
2-4
2-5
Explanation of Columns ............................................................................................
2-4
2-6
Reporting Deficiencies ..............................................................................................
2-4
2-7
Special Instructions ...................................................................................................
2-4
2-8
Test Procedures ........................................................................................................
2-15
2-3. General. Operator PMCS are performed to ensure that the MK12 SSDS is ready for operation at all times. Perform
the checks and services at the specified intervals.
a.
Before you Operate. Always keep in mind the CAUTIONS and WARNINGS. Perform your before (B) PMCS
prior to the equipment leaving its containment area or performing its intended mission.
b.
While you Operate. Always keep in mind the CAUTIONS and WARNINGS. Perform your during (D) PMCS
when the equipment is being used in its intended mission.
c.
After you Operate. Perform your after (A) PMCS after the equipment has been taken out of its mission mode or
returned to its containment area.
d.
If Equipment Fails to Operate. Perform proper troubleshooting procedures. Report deficiencies on the proper
forms as described in DA PAM 738-750, The Army Maintenance Management System.
2-3
