the cabin ceiling, starboard, and makes a nyn connection with the helium inflation sleeve. Only the amount of air necessary to bring the pressure to th~ required value should be used. 

(3) Gas Release System (See BuAer Manual 12-304 12-307). 

The gas release system includes two 20-inch gas valves, located on the port and starboard sides of the envelope at panel 34, and gores K and .L. It includes, also, two rip panels located on the top of the ship from panel 21 to 28, and from panel 53 to 59. 

(a) Gas Valves 

The gas valves are set to operate automatically when the gas pressure reaches 2-1/2-inches of water as read on the gas manometer. They can also be operated manually from the pilot’s instrument panel. The gas valves are equipped with micro switches which operate telltale lights on the pilot’s panel when the gas valve begins to open at 2-1/2-inches of water. In order to offset localized drop of pressure in the air stream and to prevent premature opening of the valves, a semi-circular windshield is attached to the envelope on the aft side of the. valve. 

CAUTION: Do not attempt to hold gas valves closed manually when . flying above-pr.essure height as _excessive pressure maY deYelop in the envelope. 

