Environmental Control System (ECS) 1-68.6 Flashcards
What does the ECS do?
provides automatic temperature and pressurization control
Heating and pressurization are provided by what?
conditioned engine bleed air.
Cockpit cooling is provided by a vapor cycle system with an engine-driven compressor.
True
A full set of environmental controls are located where?
in the front cockpit right side console
Engine bleed air is utilized for what?
1 the canopy pressurization seal 2 anti-G system 3 cockpit heating and defogging, 4 pressurization, 5 on-board oxygen generation system (OBOGS).
Bleed air is tapped where from?
the engine compressor section at the left and right P3 ports
What are the two sections of the heat exchanger assembly?
One section supports cooling for anti-G, canopy seal, and OBOGS. The other section is used for all other ECS functions
Cooling air for the heat exchanger is supplied by which two sources?
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
Bleed air from the ____side P3 port is used for the ________.
left ; OBOGS
Bleed air from the _____ side P3 port is used for _____
canopy seal, anti-G, heating/defogging, and pressurization
To prevent right side P3 bleed air from entering the cockpit do what?
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
To prevent left side P3 bleed air from entering the cockpit do what?
OBOGS supply lever OFF
The BLEED AIR INFLOW switch is a three-position switch placarded HI, NORM, and OFF. What is the difference between HI and NORM.
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.
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
7500 feet MSL
When the air conditioning compressor is operating and the aircraft is below 7500 feet MSL, the inflow valve is closed. Why?
This improves cooling performance by eliminating warm bleed air from the airflow into the cockpit environment. And pressurization is no longer needed
When the DEFOG switch is set to ON, the inflow valve is fully opened to maximize the volume of bleed air entering the cockpit.
True
The ECS has ______ temperature sensing sources
two 300 °F
The temperature of the air entering the cockpit is normally controlled automatically between _________
60 and 90 °F
If the temperature controller detects a temperature in excess of _______ at the cockpit temperature control sensor, what happens?
165 °F.
It directs the heat exchanger bypass valve to move to full
closed,
Placing the DEFOG switch to the ON position does what three things?
(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.
If the DEFOG switch is placed to OFF, the electrically controlled defog valve may take up to ________ to close
40 seconds
The first indication of icing may be what?
the start of ice accumulation on the forward canopy bow and at the base of the windshield.
Operation of the canopy defog increases _____ for a given PCL setting due to the higher bleed air load on the engine
ITT
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
47%
As the aircraft approaches ______ pressure
altitude, the control valve regulator will open and close the control valve to maintain cockpit pressure.
8000 feet
An 8000-foot cockpit altitude is maintained until a differential pressure of ________ is reached at ________
3.6±0.2 psi; 18,069 feet
Cockpit pressure altitude
at 31,000 feet is ________
16,600 feet.
If readings other than 3.6±0.2 psi are encountered at or above 18,069 feet PA, do what?
notify maintenance.
When does the amber CKPT ALT annunciator illuminate?
If cockpit pressure altitude rises above 19,000 feet, an amber CKPT ALT annunciator illuminates.
When will the red CKPT PX annunciator illuminate?
If cockpit differential pressure exceeds 3.9 to 4.0 psi, a red CKPT PX annunciator illuminates.
Cockpit differential pressure and cockpit altitude are displayed where?
on the alternate engine data displays in each cockpit.
What are the positions of the pressurization control switch, placarded PRESSURIZATION?
NORM, DUMP, and RAM/DUMP
When the pressurization control switch is in the NORM position, what happens?
the pressurization system operates automatically.
When the pressurization control switch is in the DUMP position, what happens?
Removes power from the dump solenoid which opens the dump solenoid electrically and opens the control valve mechanically; however, bleed air inflow continues
When the pressurization control switch is in the RAM/DUMP position, what happens?
opens the control valve, opens the fresh air valve, and closes the defog valve if open; however, bleed air inflow continues
Placing the BLEED AIR INFLOW switch to OFF along with RAM/DUMP does what?
will stop bleed air inflow and allow the increase of ram air flow into the cockpit.
Cockpit cooling and avionics cooling is provided by what type of system?
a vapor cycle system
The EVAP blower assembly produces up to _____-cubic-feet-per-minute flow at the HI setting
350
The evaporator blowers will be on anytime the AVIONICS MASTER switch is ON.
True
Air conditioner compressor operation has a significant effect on aircraft engine and field performance
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.
Three positions of the RAM AIR FLOW swicht?
OFF, NORM, and HI
Corresponds to the three postitions of the fresh air valve : closed, mid open, and full open.
The fresh air valve is automatically closed when approaching _______
8000 feet
