Environmental Control System Flashcards
Primary purpose of the ECS
To route compressed air from the SDC, mounted on the Midwing Gearbox (MWGB), to the ECU, located aft in the left sponson, for use by the pneumatically supported primary and secondary environmental systems.
3 Parts of the Environmental Control System
- Air Conditioning2. Avionics Cooling3. OBIGGS/OBOGS
SDC
Shaft Driven Compressor - Mounted on the MWGB, is the primary air supply source
What can power the SDC
Either the APU or the main drive system
ECU
Environmental Control Unit - Conditions air for distribution to the cockpit and/or cabin.
OBOGS
Onboard Oxygen Generating System - converts partially conditioned air supplied by the ECU into oxygen-enriched air in order to support unpressurized flight at altitudes above 10,000 feet MSL.
OBIGGS
Onboard Inert Gas Generating System - Converts partially conditioned air into Nitrogen Enriched Air (NEA) for distribution to the fuel cells. The nitrogen atmosphere within the fuel cells has an inerting effect that reduces vulnerability to fire and explosions, but it is not a fire suppression system.
OBIGGS System Pressure
Supplies 40 psi at sea level and decreases to no less than 20 psi at the aircrafts operating limit of 25,000 ft DA
Rate and output pressure of the SDC
Supllies air to the ECU at 42 pounds per minute with an output pressure of 52.8 psi.
SDC Magnetic Chip Detector
Provides signal to the Avionics Bay Interface Unit (ABIU) resulting in an SDC FAIL caution
SDC Solenoid Valve
Controls oil flow to the Inlet Guide Vanes (IGV) and the Hydraflow Surge Control Valve (SCV). It is normally closed and opens when the ECS is ON.
SDC Oil pressure sensor
Provides a signal to the CMS for a low oil pressure indication of less than 20 pounds per square inch gauge (psig).
SDC Input Drive Shaft
Engages the MWGB to the SDC at approximately 12,000 rpm.
ECS Controller
Monitors the SDC for low oil pressure, low oil level, magnetic chips, and ECU ducting leakage, while controlling the air distribution throughout the cockpit and cabin through fan and valve operations
Heat Exchangers
Provide a means in which heated compressed air from the SDC can be cooled to the desired temperature
ECU Shutoff Valve
Regulates airflow to the Primary Heat Exchanger
Emergency Vent Fan and Check Valve
Supplies unfiltered ambient air to the cockpit and cabin in the event of an ECU failure
OBOGS has ___ outlets and is designed to be used by up to ___ personnel
7; 4
Emergency Oxygen
Backup oxygen supply from Emergency O2 bottle in case of OBOGS failure
Amount of Oxygen in Emergency O2 system
400 liters