WARNING WARNING TM     10-3930-643-10 Item No. Interval B D A W 21 Operator/Crew     Preventive     Maintenance     Checks     and     Services NOTE : Within    designated    interval,    these    checks    are    to    be performed    in    the    order    listed. B - B e f o re D -    D u r i ng A -    A f t er W - W e e k ly Item    To    Be    Inspected Procedure:    Check    and    have    repaired,    filled or    adjusted    as    needed. BATTERIES Sulfuric    acid    contained    in    batter- ies    can    cause    severe    chemical burns    if    not    handled    properly. Do    not    smoke    or    allow    any    flame    or spark    in    the    vicinity    while    check- ing     the     battery. The     battery g e n e r a t e s  h y d r o g e n ,  a  h i g h ly explosive     gas. Check     electrolyte     level.     Refer     to TM    9-6120-200-14. If    level    of    electrolyte is     below     the     top     of     the     battery     plates, notify     organizational     maintenance. b. Check    battery    and    battery    box    for corrosion    and    obvious    damage. Equipment    Is    NOT READY/AVAILABLE     IF: Battery cracked, missing    or    engine will    not    crank. 2-30