Air-Conditioning General (Flight Crew Operating Manual)

R M AIR-CONDITIONING General Vol. 1 21−00−1 Nov 01/2010...

R M AIR-CONDITIONING General Vol. 1 21−00−1 Nov 01/2010 1. INTRODUCTION The Environmental Control System (ECS) provides temperature and pressure regulated air for heating, ventilating, and pressurizing the flight and passenger compartments. The airplane is pressurized from the forward pressure bulkhead to the aft pressure bulkhead. Exhaust air from these compartments is used to ventilate the avionics and cargo compartments, before being dumped overboard through an outflow valve. For ground operations, pneumatic air to operate the ECS can be obtained from: an external high−pressure ground air supply cart the Auxiliary Power Unit (APU) either or both engines a low−pressure air−conditioning connection During flight, the engines normally supply bleed air for operating the air conditioning, pressurization and avionics cooling systems. ECS warnings and cautions are displayed on the Engine Indication and Crew Alerting System (EICAS) primary page. ECS advisory and status messages are displayed on the EICAS status page. Views of the airplane ECS temperature, pressure, valve positions and system status indications are displayed on the EICAS ECS synoptic page. Flight Crew Operating Manual CSP D−013−023  R M AIR-CONDITIONING General AFT Vol. 1 21−00−2 Nov 01/2010 SAFETY PRESSURE PASSENGER VALVES (2) BULKHEAD GALLEY CABIN FLIGHT CARGO OUTFLOW GROUND COMPARTMENT VALVE COMPARTMENT VALVE LEGEND Pressurized by conditioned air GALLEY AND FORWARD AFT CARGO LAVATORY FAN EXHAUST LAVATORY SHUTOFF VALVE GALLEY EXHAUST FAN AIR CONDITIONING HEATER SAFETY AFT LAVATORY LOW PRESSURE VALVE (2) AUXILIARY AND CABIN PRESSURE GROUND POWER VENTILATION CONTROL PANEL CONNECTOR UNIT CABIN CONSOLE TEMPERATURE DISPLAY VENTS SENSOR (4) FILTER RIGHT PACK MANIFOLD MIXING PACK LEFT LOW RAM AIR FLOW INTAKE SENSOR AVIONICS RECIRCULATION FAN (2) FAN (2) DISPLAY FAN (2) GROUND GASPER CARGO OUTFLOW VALVE CABIN HEATER VALVE OVERHEAD BIN (OPTIONAL) PRESSURE DUCTING HIGH AFT CONTROLLERS PRESSURE PRESSURE (2) AIR CONDITIONING AFT CARGO BULKHEAD GROUND SYSTEM CONTROLLERS CONNECTION INLET SHUTOFF (2) VALVE Air-conditioning System – Simplified Diagram Figure 21−00−1 Flight Crew Operating Manual CSP D−013−023  R M AIR-CONDITIONING Distribution Vol. 1 21−20−1 Nov 01/2010 1. INTRODUCTION The air distribution system directs the conditioned air from the air conditioning system to the flight and passenger compartments. A recirculation system improves air flow in the passenger compartment. Ventilation systems exhaust air from the galley, lavatories and aft cargo areas. Electric fans provide avionics and cockpit display cooling. An electric galley heater provides supplementary heating for the galley and passenger door area. A. PACKs The PACKs are located in the aft equipment compartment and provide cooling of the engine or APU bleed air that is distributed to the flight and passenger compartments. Each PACK consists of an Air Cycle Machine (ACM), dual heat exchanger, reheater and condenser, which are used to decrease the temperature and water content of the bleed air used in the conditioning process. The pressurized conditioned air from both PACKs is supplied to a mixing manifold, under the aft cargo compartment floor, where the air is then distributed to the flight and passenger compartments. For normal operation, each PACK receives hot bleed air from its related engine or from the APU where it is directed to the primary core of the heat exchanger via a precooler. The primary core uses ram air to initially cool the bleed air and then the air is directed to the ACM compressor where the temperature and pressure are increased. The air is then directed back for a double pass through the main core of the heat exchanger. From the main core, the air is directed to the reheater and condenser, where water is extracted from the air and then fed to the ram air duct to be used as a cooling medium. Air from the condenser is directed through the reheater and then to the ACM turbine, where the heat energy is extracted by expanding the air. This causes a decrease in the air temperature which is then supplied to the mixing manifold of the distribution system. A Ram Air Regulating Valve (RARV), which is controlled by the ACSCs, directs ram air from the fan in the plenum to the cores of the precooler. This is done to regulate the temperature of the air from the engines to the heat exchanger. If the RARV fails, a L RARV FAULT or R RARV FAULT status message is displayed on the EICAS status page. NOTE It is recommended, under normal operating conditions, that the pack(s) be operated in AUTO mode only. The pack(s) should only be operated in MAN mode if there is a L PACK AUTOFAIL or R PACK AUTOFAIL caution message posted on the EICAS primary page. CAUTION When operating in MAN mode, the pack(s) should only be operated within their normal operating range of 5 to 85°C (41 to 185° F). In hot and humid operating conditions, the pack(s) should not be used in MAN mode to rapidly reduce the flight compartment or cabin temperatures as this can cause damage to system components if the temperature limits are not respected. Flight Crew Operating Manual CSP D−013−023  R M AIR-CONDITIONING Distribution Vol. 1 21−20−2 Nov 01/2010 A A AIR CONDITIONING UNIT RAM AIR RAM AIR WATER VALVE INLET SPRAYER DUAL HEAT TO FLIGHT EXCHANGER FWD COMPARTMENT SUPPLY DUCT MAIN CORE PRIMARY CORE AFT PRESSURE PACK BULKHEAD TEMPERATURE BLEED AIR FROM SENSOR COMPRESSOR FLOW CONTROL DISCHARGE VALVE PACK DISCHARGE TEMPERATURE T T SENSOR TEMPERATURE SENSOR PLENUM TO REHEATER PRE−COOLER T AND EXHAUST CONDENSER TURBINE WATER EXTRACTOR COMPRESSOR TEMPERATURE P CONTROL VALVE ACM PACK DISCHARGE PRESSURE SENSOR (ABOVE MIXING MANIFOLD) Air-conditioning Unit – Schematic Figure 21−20−1 Flight Crew Operating Manual CSP D−013−023 R M AIR-CONDITIONING Distribution Vol. 1 21−20−3 Rev. 18, Sep 06/2019 Air−Conditioning Panel Overhead Panel TEMP (amber) Indicates high temperature sensed in respective pack outlet. AUTOFAIL (amber) Indicates failure of respective pack in automatic mode. ECS Page PACKs Controls and ECS Synoptic Page Indications Figure 21−20−2 Flight Crew Operating Manual CSP D−013−023 R M AIR-CONDITIONING Distribution Vol. 1 21−20−4 Rev. 3, May 02/2011 L or R PACK AUTOFAIL caution (amber) Indicates failure of respective pack in automatic mode and system is not in manual mode. L PACK TEMP or R PACK TEMP caution (amber) Indicates a high (>85°C) or low (