The check valve locking device should be closed and locked at initial position. The locking device is closed for crew cockpit conditioning lines deactivation on surface processing of special equipment having the surface conditioner connected.
The check valve with locking device is set on the back wall of frame №14 in cargo cabin.
The crew cockpit conditioning line from the surface conditioner after check valve with lock has socket checked valve welded though which the air from cabin comes inside ACS in case of both ACS subsystems refusal during flight, which excludes the formation of air pressure drop between internal pipelines and cockpit cavities, and consequently, the pipelines bearing.The temperature control in the cockpit is conducted in accordance with electric thermometer temperature indicator ТП-4, located in the right upper side at conditioning panel. The signal to indicator is sent from ПП-9Т temperature indicator, located in the cockpit near frame No.3