TM 1-1510-223-10 Table 2-5.  Oxygen Duration in Minutes 140 Cubic Foot System CABIN CREW TOTAL DURATION PRESSURE MASK FLOW IN ALTITUDE CONDITION LPM-NTPD MINUTES (1) TWO MAN 35,000 100% 6.3 512.1 CREW 31,000 100% 8.4 384.0 25.000 100% 11.8 273.3 20,000 100% 15.2 212.2 20,000 NORMAL 7.2 448.0 15,000 100% 19.0 169.7 15,000 NORMAL 10.2 316.2 10,000 100% 23.8 135.5 10,000 NORMAL 13.8 233.7 35,000 100% 10.0 323 31,000 100% 12.1 266.6 25,000 100% 15.5 208.1 TWO MAN 20,000 100% 18.9 170.7 CREW PLUS 20,000 NORMAL 10.9 295.9 ONE PASS 15,000 100% 22.7 142.1 15,000 NORMAL 13.9 232.1 10,000 100% 27.5 117.3 10,000 NORMAL 17.5 184.3 (1)  For 100% capacity of usable oxygen, 3,226 L. BT00197 shut-off  valves  are  open  and  if  there  is  pressure  in  the cylinders.  Each individual places the supply lever (green) on the regulator control panel to the ON position, and the diluter lever (white) to the NORMAL OXYGEN position. d. Emergency Operation.  For emergency operation, the   affected   crew   member   selects   the   EMERGENCY position of the emergency pressure control lever (red) on his regulator control panel.  This selection provides 100% corygen at a positive pressure, regardless of the position of the diluter control lever. e. First  Aid  Operaton.    A  first  aid  oxcygen  mask  is installed   in   the   aft   cabin   area   as   a   supplemental   or emergency source of oxygen.  The mask is stowed behind an   overhead   cover,   placarded   FIRST   AID   OXYGEN   - PULL Removing the cover allows the mask to drop out of the  container,  exposing  a  manual  control  valve,  which releases   oxygen   to   the   mask   when   placed   in   the   ON position.    After  using  the  mask,  the  manual  valve  in  the container  must  be  turned  OFF  before  stowing  the  mask and replacing the cover. f. Oxygen Duration Examples. (1)   Example one. (a)   Wanted.    Duration  in  minutes  of  oxygen at 100% capacity. (b)   Known.      'Iwo     man     crew     plus     one passenger,   cabin   pressure   altitude   =15,000   feet,   crew masks, normal, 100% capacity. (c)    Method.     Find  "two  man  crew  plus  one pass " line (table 2-5), move right then down to 15,000 - "normal", read 232.1 minutes. (2)   Example two. (a)   Wanted.  Duration of oxygen for previous example data at 84% of capacity. (b)   Known.  232.1  minutes  duration  at  100%, 84% capacity, total aircraft flow = 13.9 LPM. (c)    Method.    Multiply  232.1  X  0.84  =  194.9 minutes, or Multiply 3,226 X 0.84 =2709.8, divide by 13.9 LPM = 194.9 minutes. (3)   Example three. (a)   Wanted. Duration of oxygen for complement at other cabin pressure altitude, at less than 100% capacity. (b)       Known.       -Cylinder    at    84%    capacity, 100% capacity = 3,226 L, cabin pressure altitude = 21,000 feet 2-56