Environmental Control System (ECS) 1-68.6

Question 1

What does the ECS do?

Answer 1

provides automatic temperature and pressurization control

Question 2

Heating and pressurization are provided by what?

Answer 2

conditioned engine bleed air.

Question 3

Cockpit cooling is provided by a vapor cycle system with an engine-driven compressor.

Answer 3

True

Question 4

A full set of environmental controls are located where?

Answer 4

in the front cockpit right side console

Question 5

Engine bleed air is utilized for what?

Answer 5

1 the canopy pressurization
seal
2 anti-G system
3 cockpit heating and defogging, 
4 pressurization,
5 on-board oxygen generation system (OBOGS).

Question 6

Bleed air is tapped where from?

Answer 6

the engine compressor section at the left and right P3 ports

Question 7

What are the two sections of the heat exchanger assembly?

Answer 7

One section supports cooling for anti-G, canopy seal, and OBOGS. The other section is used for all other ECS functions

Question 8

Cooling air for the heat exchanger is supplied by which two sources?

Answer 8

For ground operations, a blower supplies the necessary cooling air flow
With weight off the landing gear, electrical power to the blower is terminated and ram air through the cooling air inlet is ducted to the heat exchanger

Question 9

Bleed air from the ____side P3 port is used for the ________.

Answer 9

left ; OBOGS

Question 10

Bleed air from the _____ side P3 port is used for _____

Answer 10

canopy seal, anti-G, heating/defogging, and pressurization

Question 11

To prevent right side P3 bleed air from entering the cockpit do what?

Answer 11

both the BLEED AIR INFLOW switch on the environmental control panel and the DEFOG switch on the center console must be in the OFF position

Question 12

To prevent left side P3 bleed air from entering the cockpit do what?

Answer 12

OBOGS supply lever OFF

Question 13

The BLEED AIR INFLOW switch is a three-position switch placarded HI, NORM, and OFF. What is the difference between HI and NORM.

Answer 13

the position of two solenoids on the inflow valve.

• In the OFF position, both solenoids are de-energized and the valve is closed.
• In the NORM position, one solenoid is energized allowing the inflow valve to partially open.
• When the switch is set to HI, the second solenoid is energized and airflow through the valve increases.

Question 14

When the air conditioning compressor is operating and the aircraft is below __________ (pressurization no longer required) the inflow valve is automatically closed regardless of the position of the BLEED AIR INFLOW switch

Answer 14

7500 feet MSL

Question 15

When the air conditioning compressor is operating and the aircraft is below 7500 feet MSL, the inflow valve is closed. Why?

Answer 15

This improves cooling performance by eliminating warm bleed air from the airflow into the cockpit environment. And pressurization is no longer needed

Question 16

When the DEFOG switch is set to ON, the inflow valve is fully opened to maximize the volume of bleed air entering the cockpit.

Answer 16

True

Question 17

The ECS has ______ temperature sensing sources

Answer 17

two 300 °F

Question 18

The temperature of the air entering the cockpit is normally controlled automatically between _________

Answer 18

60 and 90 °F

Question 19

If the temperature controller detects a temperature in excess of _______ at the cockpit temperature control sensor, what happens?

Answer 19

165 °F.
It directs the heat exchanger bypass valve to move to full
closed,

Question 20

Placing the DEFOG switch to the ON position does what three things?

Answer 20

(1) the defog valve is opened, increasing the bleed air supply (2) the inflow valve is automatically set to high, further increasing the amount of bleed air entering the cockpit,
(3) the air conditioning compressor is automatically turned on to dry the air.

Question 21

If the DEFOG switch is placed to OFF, the electrically controlled defog valve may take up to ________ to close

Answer 21

40 seconds

Question 22

The first indication of icing may be what?

Answer 22

the start of ice accumulation on the forward canopy bow and at the base of the windshield.

Question 23

Operation of the canopy defog increases _____ for a given PCL setting due to the higher bleed air load on the engine

Answer 23

ITT

Question 24

A reduction in flaps UP climb performance of up to ____ may be observed with the defog ON and the PCL retarded to maintain the ITT within limits

Answer 24

47%

Question 25

As the aircraft approaches ______ pressure

altitude, the control valve regulator will open and close the control valve to maintain cockpit pressure.

Answer 25

8000 feet

Question 26

An 8000-foot cockpit altitude is maintained until a differential pressure of ________ is reached at ________

Answer 26

3.6±0.2 psi; 18,069 feet

Question 27

Cockpit pressure altitude

at 31,000 feet is ________

Answer 27

16,600 feet.

Question 28

If readings other than 3.6±0.2 psi are encountered at or above 18,069 feet PA, do what?

Answer 28

notify maintenance.

Question 29

When does the amber CKPT ALT annunciator illuminate?

Answer 29

If cockpit pressure altitude rises above 19,000 feet, an amber CKPT ALT annunciator illuminates.

Question 30

When will the red CKPT PX annunciator illuminate?

Answer 30

If cockpit differential pressure exceeds 3.9 to 4.0 psi, a red CKPT PX annunciator illuminates.

Question 31

Cockpit differential pressure and cockpit altitude are displayed where?

Answer 31

on the alternate engine data displays in each cockpit.

Question 32

What are the positions of the pressurization control switch, placarded PRESSURIZATION?

Answer 32

NORM, DUMP, and RAM/DUMP

Question 33

When the pressurization control switch is in the NORM position, what happens?

Answer 33

the pressurization system operates automatically.

Question 34

When the pressurization control switch is in the DUMP position, what happens?

Answer 34

Removes power from the dump solenoid which opens the dump solenoid electrically and opens the control valve mechanically; however, bleed air inflow continues

Question 35

When the pressurization control switch is in the RAM/DUMP position, what happens?

Answer 35

opens the control valve, opens the fresh air valve, and closes the defog valve if open; however, bleed air inflow continues

Question 36

Placing the BLEED AIR INFLOW switch to OFF along with RAM/DUMP does what?

Answer 36

will stop bleed air inflow and allow the increase of ram air flow into the cockpit.

Question 37

Cockpit cooling and avionics cooling is provided by what type of system?

Answer 37

a vapor cycle system

Question 38

The EVAP blower assembly produces up to _____-cubic-feet-per-minute flow at the HI setting

Answer 38

350

Question 39

The evaporator blowers will be on anytime the AVIONICS MASTER switch is ON.

Answer 39

True

Question 40

Air conditioner compressor operation has a significant effect on aircraft engine and field performance

Answer 40

False. Air conditioner compressor operation has negligible effect on aircraft engine and field performance. Air conditioning may be on for
all takeoffs, landings, and ground operations without affecting aircraft/engine performance.

Question 41

Three positions of the RAM AIR FLOW swicht?

Answer 41

OFF, NORM, and HI

Corresponds to the three postitions of the fresh air valve : closed, mid open, and full open.

Question 42

The fresh air valve is automatically closed when approaching _______

Answer 42

8000 feet