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ERJ 170 ECS System
Environmental Control System Questions
Question | Answer |
---|---|
What does the AMS use bleed air for? | • ECS (heating & cooling)• Engine start• Pressurization• Engine and wing anti-ice• Water pressure• Hot air leak detection |
How many AMS controllers are installed? | • One controller with 2 channels which control the respective onside system |
What happens if a channel fails? | • The remaining channel is able to control the entire AMS |
What provides air for the AMS? | • Engine bleeds• APU bleed• External Pneumatic Source |
What is bleed air used for? | • ECS (heating & cooling)• Engine start• Engine and wing anti-icing• Water pressurization |
What is external pneumatic air used for? | • ECS on the ground• Engine start on the ground |
Where is the external ground source panel located? | • Lower fairing between the wings |
What is the primary use for APU bleed air? | • ECS on the ground• Engine starting on the ground• Electrical source (< FL330)• Assist with engine start (< FL210)• Bleed source for pressurization, heating, and cooling (< 15,000 ft MSL) |
Can engine bleed air flow-back to the APU? | • No. A check valve prevents flow-back |
Where is bleed air tapped from the engines? | • 6th and 10th stage compressors (EBV and HSV respectively)• System alternates between valves to regulate an adequate and safe pressure |
What is normal pressure for any engine operation? | • 45 psi |
What is the purpose of the pre-cooler? | • Cools the bleed air coming from the engine to the AMS |
What cools the pre-cooler? | • Ground N1 fan• Flight N1 fan or ram air |
What does the Overheat Detection System (ODS) observe? | • Engine bleeds and packs• APU bleed• Plumbing for the wing and engine anti-icing system |
Do both loops have to function in order to detect on overheat condition? | • Yes, but if one fails the other will work alone to detect the overheat |
How many ECS packs are on the airplane? What provides air for the packs? | • 2 independent packs (left and right)• Each engine provides bleed air to it’s respective pack |
Can a single pack provide adequate temperature control and pressurization? | • Yes, up to FL310 |
Can a single bleed source power both packs? | • Yes, through the crossbleed valve |
What is the ratio of fresh air to recirculated air? | • 52% fresh air to 48% recirculated air |
When are the recirculation fans commanded off? | • Cockpit switch• Smoke detected in the recirc bay• DUMP button is pressed• Respective pack is commanded off |
What keeps the 3 avionic E-BAYs cool? | • FWD & CTR E-BAY 3 fans each pull air from cabin to bay• AFT E-BAY Natural air-flow from cabin to bay |
When is the Emergency Ram Air Ventilation activated? | • Both packs commanded or failed OFF below 25,000 ft (via left side and electronically controlled)• Ram air pressure greater than cabin pressure (via right side) |
How many channels on the Cabin Pressure Control (CPC)? | • 2 channels, one active and one in standby mode |
Where does the CPC get Landing Field Elevation (LFE)? | • FMS or can be manually selected |
What happens when the dump button is pressed? | • Commands both ECS packs OFF• Opens OFV and raises the cabin to 12,400 ft at a rate of 2,000 fpm |
Can the cabin altitude be raised higher than 12,400 ft? | • Yes, by using manual mode • Cabin altitude will rise due to natural leak |
In manual mode will the cabin depressurize on landing? | • No |
What is the bleed system priority in flight? | • Onside engine• Opposite side engine• APU (if available) |
If engine and APU bleed air are available simultaneously, which has priority? | • APU has priority if Aircraft is on the ground Wheel speed < 50 kts Opposite engine bleed pressure is not enough for engine start |
When will the crossbleed valve automatically open? | • Only one side bleed source is available• Engine 2 start in the air• Engine 1 start in the air if APU is not available |
What are some things that will close the ECS packs? | • Any engine start if APU is the bleed source• Engine start on the ground• Respective bleed system duct leak• Bleed air source not available for the pack |
What are some things that will close the ECS packs? | • TL set to MAX on takeoff• REF A/I set to ALL on takeoff• REF ECS set to OFF on MCDU (APU is OFF) |
When are ECS packs recovered? | • TL not at MAX, and Airplane is 500 AFE with both engines operating Airplane is > 9,700 MSL with one engine operating |
What happens if smoke is detected in the recirculation bay? | • Both recirc fans deactivate• Cargo recirc fan deactivates• Cargo outflow valve closes |
Where does the CPCS get cruise flight level & landing elevation from? | • FMS before takeoff or CPCS calculates using ambient pressure• LFE may be manually inputted |
What color is the LFE on the EICAS? | • Green FMS input• Cyan Manual input (an ‘M’ will be in front of LFE) |
What is the ABORT mode? | • Cabin is scheduled back to the takeoff altitude if Airplane stops climbing and begins a descent, and Airplane has not climbed > 5,000 AFE or > 10,000 MSL |