21-01 Air Conditioning Packs
21-02 Pack Airflow/Shut Off Valves
21-03 Pack Trip Warning Systems
21-04 Pack Turbofans
21-05 Pack Ram Air System
21-06 Pack Turbofan Valves
21-07 RAM DOOR FULL OPEN Indicating Lights
21-08 Air Mix Valves
21-09 Air Mix Valve Position Indicators
21-10 Cabin Rate of Climb Indicator
21-11 Cabin Altitude Warning System
21-12 Cabin Altitude Indicator
21-13 Cabin Differential Pressure Indicator
21-14 Cabin Pressure Control System
21-15 Main Outflow Valve
21-16 Pressure Relief Valves
21-17 Temperature Indicators
21-18 DUCT OVERHEAT Warning Lights
21-19 Passenger Cabin Temperature Control Systems
21-21 Flight Deck Temperature Control Systems
21-22 Forward Outflow Valve
21-25 Water Separator Anti-Icing Systems
21-26 Ground Preconditioned Air Connection Check Valve
21-27 Electrical/Electronic Equipment Cooling Blowers
21-29 Air Cleaner Purge Valves
21-31 Recirculation Fan(s)
21-32 Pack Temperature Control Systems
21-33 Primary Pack Temperature Control Valves
21-34 Standby Pack Temperature Control Valves
21-35 Trim Air Pressure Regulating and Shutoff Valve
21-36 Trim Air Modulating Valves
21-37 Outflow Valve Heater Gasket
21-38 Outflow Valve Position Indicator
21-39 Trim Air Check Valve
21-40 Equipment Cooling Automatic Flow Control Valve/Overboard Exhaust Valve
21-50 Flight Deck Foot Air