Section III. OPERATING UNDER USUAL CONDITIONS
2-3. OPERATING PROCEDURE
This section contains information on the fitting, adjusting and operation of the flyer's protective helmet. The
wearer's safety and comfort depends on the correct adjustment and fit. Proper fit and adjustment assures
maximum comfort and stability of the helmet and prevents interference with combat efficiency. To provide
the maximum protection, sound attenuation and comfort, the helmet should fit snugly at the cheeks,
forehead, and nape of the neck. Helmets that are loose fitting can produce areas of pressure and
discomfort. Fitting that results in abnormal pressure and discomfort after a short time must be corrected.
Helmet size is determined by the hat size. Up to hat size 7-1/4 uses the SPH-4 Regular size helmet. A
person whose hat size is 7-1/4 and larger, uses the SPH-4 Extra Large size helmet. Females should wear
hair pinned up over scalp during try-on period. Due to bulk of long hair they may have to wear Extra Large
Don the helmet by placing both thumbs on the inside of the ear cups and pulling the sides of the helmet
between the thumbs and roll the helmet backwards until it is properly positioned on the head. Make the
following crown strap adjustments to allow the head to be sealed as far into the helmet as possible without
either obstructing vision or touching the inner foam liner, making sure the ears are comfortably enclosed by
the ear cup and that all three crown straps have the same tension when the crown pad is pressed in the
Crown Straps (1) Adjustment.
Straps should be adjusted equally to eliminate "Hot Spots."
There should be 1/2 in. of space between the helmet liner
and crown pad of the suspension assembly.
This adjustment raises or lowers helmet to desired
position. Adjust helmet height with relation to the ear
cups. Make certain that the ears are comfortably enclosed
by the cups.
(1) To raise Helmet:
Tighten the strap in the adjustment buckle
(2 or 3) of each strap as required.
(2) To Lower Helmet:
Loosen the strap in the adjustment buckle (2
or 3) of each strap as required.