TM 5-1940-321-13&P
( 24 ) Check the overpressure release function for smooth operation by pulling the
valve flywheel away from the craft. When released, the flywheel should return
to its original position.
( 25 ) Replace the metal valve insert and the metal valve cap. Tighten each firmly by
hand.
( 26 ) Repeat the above procedure for the three remaining intercommunicating
valves.
5-14. KEEL VALVE CLEANING AND INSPECTING. The keel valve must be cleaned and inspected
every 6 months during periods of craft use. This procedure is performed by direct support personnel.
a. Tools, Materials, and Parts. The same tools, materials, and parts should be available as
specified for serving the intercommunicating valves in paragraph 5-13.
b. Keel Valve Cleaning Procedures. Clean and inspect the keel valve as follows:
NOTE:
This operation must be performed with the keel inflated.
( 1 ) Verify that the keel valve base nut is moderately tight using the collar nut
spanner as shown in figure 5-11. Do not over-tighten. If not tight, usually only
1/8 to 1/4 turn of the spanner is required. Over-tightening can cause the valve
base on the inside of the keel to turn.
Figure 5-11. Checking Tightness of Keel Valve Base Nut (to be done while keel is inflated at
220/240 mb [3.2/3.5 psi])
5-23