TM 5-4220-226-14&P 2-2.  Introduction - continued. Table 2-1.  Operator's Preventive Maintenance Checks and Services - CONT Item No Interval Location Item to check service Procedure Not fully mission capable if: 11 Before EXTERIOR Inspect the cable for cracks, signs of Communications deterioration, or any other damage.  Check Whip the connector for cracks, corrosion, bent pins or any other damage. 12 Before INTERIOR Inspect cushion for holes, tears, rips, or Helmet Liner other damage.  If foam is saturated with water, squeeze it out.  Ensure head cushion is dry and properly fastened inside the helmet. 13 Before EXTERIOR Inspect shell and face plate for gouges, Damage exceeds listed Helmet Shell chips, and deep scratches.  If scratches tolerance. are 1/32 inch deep or deeper and more than 1 inch long, replace part or select alternate helmet to continue with the dive. 14 Before INTERIOR Inspect microphone and earphones. Communication system Communications Ensure they are dry and undamaged. not operative. Set Inspect wires and communications connectors to ensure they are clean and undamaged.  Check for corrosion and breaks in the wires. 15 Before EXTERIOR Clear umbilical of moisture and Umbilical shows signs of Umbilical contaminants by connecting the umbilical cracks, bulges, or sticky to an air source.  Hold open end of surface texture. umbilical while starting air flow and Hose manufacture dates increase slowly.  Run air flow until hose is are not within specifica- purged of moisture, dust, and any other tions prescribed by contaminants.  Shut off air supply at FM 20-1 1 -1, Military source.  Inspect umbilical for cracks, Diving Manual. bulges, or sticky surface texture.  Ensure umbilical hose manufacture dates are within specifications prescribed by FM 20-11-1, Military Diving Manual. 16 Before EXTERIOR Inspect hose and fittings for date of Hose is not within Helmet Adapter manufacture/testing.  Ensure assembly is specifications for service Hose within specifications for service life life/testing. prescribed by FM 20-11-1, Military Diving Hose shows signs of Manual.  Inspect for damage such as cracks, bulges, or sticky cracks, breaks, or sticky surface texture, surface texture. and extensive wear. 2-4