21C Safety & Warning Devices
TTP B1-L3 ATA 21C Beech 90 Series B2-L3 Safety and Warning Devices Outflow and Safety V alves The outfl o w and safety v al v es are mounted in the b ulkhead at the rear of the cabin. The v al v es are the same b ut are plumbed with different hard w are to esta b lish their function. Both v al v es inco r porate a n e g at i v e pressure relief diaphragm with cabin pressure on one side and atmospheric pressure on the othe r . If atmospheric pressure e xceeds cabin pressure, the diaphragm opens the v al v e to reli e v e cabin n e g at i v e pressure. Both v al v es are also equipped with a maximum differential diaphragm and v al v e assem b l y , preset at 5.0 psi d , that will pr e v ent the cabin from o v e r pressurizing. Th e outfl o w v al v e automatical l y meter s th e outfl o w o f cabi n ai r durin g press...