Enviornmental Control System

Question 1

What does the ECS do on a basic level?

Answer 1

Takes engine bleed air, cools it, and delivers it to the cabin for ventilation and pressurization.

Question 2

Anytime the starter is activated the ECS will?

Answer 2

Automatically shut down.

Question 3

What automatically selects either P2.5 or P3 air?

Answer 3

High Pressure Shutoff Valve

Question 4

When does the system use P3 vs. P2.5?

Answer 4

More than 80% NG uses P2.5.

Less than 80% NG uses 3.0.

Question 5

How many ports do 2.5 vs. 3.0 air have?

Answer 5

Single port for 2.5

Dual ports for 3.0

Question 6

What does the TCV valve do?

Answer 6

Valve controls how much air enters the heat exchanger and how much bypasses it.

Question 7

If temperature is less than desired what does the TCV do?

Answer 7

Bypass more air past the heat exchanger.

Question 8

If temperature is higher than desired what does the TCV do?

Answer 8

Duct more air into the heat exchanger.

Question 9

How is the TCV controlled in AUTO mode?

Answer 9

By signals sent from the cabin temperature sensor located in the cabin headliner.

Question 10

How is the TCV controlled in MANUAL mode?

Answer 10

Directly controlled by the guarded temperature switch.

Question 11

How is air that enters the heat exchanger cooled?

Answer 11

Ambient NACA air is drawn into the Heat Exchanger and water is injected to assist in cooling.

Question 12

After air leaves the heat exchanger where does it go??

Answer 12

The Cooling Turbine and is then joined with air that bypassed the heat exchanger.

Question 13

After air passes the Cooling Turbine where does it go?

Answer 13

The Water Separator to remove any moisture before entering the cabin.

Question 14

Normal GROUND operation, pressurization switch in AUTO, condition lever in GND IDLE, and electrical power supplied to the system what position is the solenoid valve in?

Answer 14

OPEN and the airplane will be unpressurized.

Question 15

When the condition lever is moved to FLT IDLE just prior to takeoff what happens to the solenoid valve?

Answer 15

Electrical power is removed and the valve closes.

Question 16

What is provided for ECS Overheat/Overpressure Protection?

Answer 16

Two over temp switches.

One over pressure switch.

Question 17

What happens in the ECS is any of the two over temp switches or one over pressure switch are activated?

Answer 17

The Primary Shut-Off Valve will close.

Amber CAWS ECS will be annunciated.

Question 18

What does the supplemental heating system consist of?

Where are they?

Answer 18

Two 28 VDC heating units.

1. U/F (under floor heater) under the cabin floor near the cockpit.
2. Cabin Heater under the cabin floor near the cargo bay area.

Question 19

What do the two Heating Units consist of?

Answer 19

A fan motor.
Heating element.
Thermal protection switch.

Question 20

What provides the RECIRC air?

Answer 20

Two blower assemblies located at the rear of the cabin.

Question 21

How is power controlled for both the compressor and evaporator fans?
(OHP)

Answer 21

On the overhead panel, under COOLING, selecting the SYS switch to ON or OFF.

Question 22

On the overhead panel under COOLING there is a switch for RECIRC or COOL, what does this do?

Answer 22

RECIRC supplies power to the evaporator fans only.

COOL supplies power to the fans and compressor.