TM 1-1510-262-10
h. Oxygen Duration Example Problem.
(1)
Example one.
WANTED
Duration in minutes of oxygen at 100% capacity.
KNOWN
Two man crew plus one passenger, cabin pressure altitude = 15,000 feet, crew masks, normal,
100% capacity.
METHOD
Find "two man crew plus one pass" line, move right then down to 15,000 - "normal" read 232.1
minutes.
(2)
Example 2.
WANTED
Duration of oxygen for previous example data at 84% of capacity.
KNOWN
232.1 minutes duration at 100%, 84% capacity, total aircraft low = 13.9 LPM.
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 3.
WANTED
Duration of oxygen for complement at other cabin pressure altitude, at less than 100% capacity.
KNOWN
Cylinder at 84% capacity, 100% capacity = 3,226 L, cabin pressure altitude = 21,000 feet. 1 crew
mask = LPM (100%), 1 passenger mask = LPM.
METHOD
Multiply 3,226 L X 0.84 = 2.709.8 L, multiply 2 crew X 7.2 LPM = 14.4 LPM, multiply 1 passenger
X 3.7 LPM, add 14.4 LPM crew plus 3.7 LPM passenger = 18.1 LPM. Divide 3,226 L by 18.1
LPM = 178.2 minutes.
i. Oxygen Cylinder Capacity Example Problem. Oxygen cylinder capacity is determined by using igure 2-32.
(1)
Example 1.
WANTED
Percent of capacity at known pressure and temperature. Pressure when temperature decreases.
KNOWN
Pressure = 1,600 PSIG stabilized cylinder temperature is estimated at 20 C decreased stabilized
cylinder temperature is estimated at -30C.
METHOD
Enter 1600 PSIG move up to 20 C line, move right to 84%. Move left on 84% line to -30 C line,
move down to 1250 PSIG.
2-62
