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107.1 Discuss the purpose of aircraft cabin pressurization and air conditioning.

The air-conditioning and pressurization system provides crew environment control and electronic equipment cooling both in flight and on the ground. Oxygen is required above 10,000 feet of altitude in an unpressurized cabin. The P-3 pressurization system allows the crew to move about freely in the airplane at altitudes above 10,000 because the system keeps the cabin pressurized to the equivalent of an altitude less than 10,000 feet.

107.2 Discuss the purpose of aircraft oxygen systems.

The oxygen system is designed to supply an active flightcrew of three members for approximately 3.5 hours at an altitude of 25,000 feet. Oxygen is supplied from three high-pressure (1,800psi) bottles through three regulators, one for each flight crewmember. A common manifold allows oxygen to be evenly furnished from one or all three bottles through a pressure reducer to the oxygen regulators.

Seven portable oxygen bottles are stowed at the tactical crew stations except station 9 and 10, whose bottles are located at the aft end of the sonobuoy storage bins. On P-3 A/B, four portable oxygen bottles are stored at the bulkhead forward of the starboard forward observer, and three are stored above the aft radar rack. These bottles are normally equipped with diluter-demand regulators and smoke masks. With the regulator set for 100% oxygen and with the user experiencing little or no physical exertion, approximately 22 minutes of oxygen are available. For the same person performing moderate work, consequently breathing at a faster rate, approximately 5 to 10 minutes of oxygen are available per bottle.