TM 10-3930-659-10 3-12.  CHECK AND CLEAN CAB AIR FILTERS (Con’t). b.  Check and Clean Cab Fresh Air Filter. (1) Open fresh air filter door (7), remove four wingnuts (5), and filter mounting frame (4).  Remove air filter (6) from door.  Check air filter for damage or dirt. (2) Clean air filter (6) by: (a) Tapping air filter (6) on flat surface with dirty side down. WARNING Compressed   air   used   for   cleaning   or   drying   purposes,   or   for clearing  restrictions,  should  never  exceed  30  psi  (207  kPa).    Wear protective clothing (goggles/shield, gloves, etc.) and use caution to avoid Injury to personnel. (b) Using compressed air opposite to normal air flow, remove dirt from air filter (6). (3) Install air filter (6) on door (7), with air flow arrow pointing up.  Position mounting frame (4) over air filter and secure with four wingnuts (5).  Close air filter door. 3-20