I am going to was the windows.
Push button, Pull handle aft, Turn window crank.
Orange band on the button indicates that the window is not locked.
The window moves inboard then begins to travel back along the track.
Now I will crawl out the window and was the windows.
This is the maintenance access terminal where I can do a wide range of tests and other functions
from.
Now I am going to conduct a test of the cabin temperature control system in preparation
for opening the ram air inlet door and turning on the air conditioning pack.
When all of the prerequisite conditions for the test are met then it displays the ready
message.
Now the test is operating.
Go to maintenance display.
Select air synoptic page.
The test is operating the ram air inlet which can be seen here moving through its range
of motion open and closed.
As soon at the test is completed I will run a special function and open the ram air inlet
door.
We close those to keep the birds from building nests in there during
parking.
The
test is still operating.
Waiting.
Now it is closing the ram air door in stages to test that the system has control of the
door actuators.
The test is completed.
Now I will run the special function to open the ram air door.
No prerequisite conditions for this function.
Start the function.
Operating.
Ram air door is opening.
Now to turn on the bleed air from the APU and turn on the air conditioning packs.
Different temperature control zones.
Actual temp, Target temp, duct temp, trim valve.
The duct temp is a mixture of cold air from the mix manifold and hot trim air.
The trim air valve modulates to regulate the amount of hot air mixes to achieve the target
temp.
These display the data for the left and right packs.
Now I am going to open the outflow valves that were closed to keep birds out.
You can see their status displayed at the bottom of the center upper screen where is
shows FWD and AFT.
When we are in flight the outflow valves will automatically modulate to control the cabin
pressure.
Now they are set to automatic mode for the flight.
The APU bleed air and engine bleed air switches.
The right engine feeds the right system and the left feeds the left.
If there is a problem and one side stops supplying bleed air then the isolation valves will automatically
open so the the engine that is still supplying the bleed air will then supply both the left
and right systems.
this is the wing anti-ice.
It sends hot bleed air from the engine to the leading edges of the engine inlets, wings,
horizontal and vertical stabilizers to keep ice from forming.
We will display the air
system page.
The green box is the APU and it shows that it is running and ready to supply bleed air.
The valves turn green when they open.
Now the duct is pressurized but there is no airflow yet so the lines stay white but the
pressure value is displayed in the box to each side.
Now I will turn on the left pack to start cooling air for the cabin.
Watch this area.
Now the display shows that the pack is operating.
This is very hot air coming from the APU compressor section.
Maybe 350-400 degrees F. Hot air goes into the pack to be cooled down and hot air goes
around into the trim system to be remixed with the cold air to regulate the temperature
to a comfortable level.
The pack will discharge the air at about 33 degrees F. The air that goes into the pack
is run through a turbine in reverse so the instead of compressing the air it expands
the air which results in a sharp drop in temperature of the expanding air.
It is also run through a drying system to remove humidity from the air to prevent freezing
in the ducting.
The left pack it flowing and we can see its operating values here.
Outlet temp is currently -4 F. Pack inlet temp is 349 F. That is the temp of the air
coming from the APU entering the pack.
It passes the first heat exchange and drops to 191 F. Goes through the secondary heat
exchanger and is 90 F. Now as I turn on the right pack the pressure in
the ducts drops.
This is 35 psi in a 6" diameter pipe so there is a huge amount of
air flowing now.
You
can see the trim air valves are moving to regulate the duct temperature
to achieve the target set temps.
The two packs dump the conditioned air into the
mix manifold which is a large mixing cylinder that takes recirculation air and fresh outside
air and blends them together as required.
If we want we can turn off the recirculation fans and only run fresh outside air through
the mix manifold.
Normal mode is to operate with recirculation fans running.
You can see how the trim air valves will work to regulate each zone up or down based on
its current status and the target temp set for each zone.