Great question. Cabin air temperature is controlled by using a mix of pure bleed air, which is always hot, a little less than 500 degrees fahrenheit, and ACM conditioned air, which is always cold, about 40 degrees fahrenheit. The ratio of hot or cold air determines the air temperature coming into the cabin. On a hot day you might have pure cold air with little to no hot bleed air. On a cold winter day you might have mostly hot bleed air with just enough cold ACM air to bring the temperature down to 200-250 degrees fahrenheit. Does this answer your question?
@@romanmandeleil In the case of the EMER pressure source, there is no way to regulate cabin temp. It's hot bleed air coming straight into the cabin. The only way to manage cabin temp under this circumstance is to reduce the power on the left engine, thereby reducing bleed air volume, or by descending to a low enough altitude to not need the pressurization system and turn the pressurization system off entirely by selecting a pressurization source of OFF.
Do you have any experience of something like that? It sounds very scary to push hot bleed air directly into the cabin. What temperature range are we talking about while regulating with left throttle?
@@romanmandeleil I've never had to deal with that situation for long. The most common reason for the ACM to shutdown is an overheat situation when basically the internal components of the ACM are too hot and it shuts down to protect itself. EMER pressurization automatically activates. All the pilot needs to do is give the ACM a few seconds to cool down, select a warmer cabin temp to prevent the ACM from overheating again, and reset the system. So EMER pressurization is only on for thirty seconds or so, at most. It definitely gets warmer in the cabin, but it's not terrible. Think of sitting in a car without the air conditioner working on a warm day. It's not the most comfortable, but a pilot can still get the job done.
Excellent!!!!! Thank you so much.
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Excellent job teaching.
Thank you so much! your clips are very well done explained.
Thanks for watching! I'm glad you find them useful.
Never understood how the temperature is actually managed while by passing the ACM . What is your take on that?
Great question. Cabin air temperature is controlled by using a mix of pure bleed air, which is always hot, a little less than 500 degrees fahrenheit, and ACM conditioned air, which is always cold, about 40 degrees fahrenheit.
The ratio of hot or cold air determines the air temperature coming into the cabin. On a hot day you might have pure cold air with little to no hot bleed air. On a cold winter day you might have mostly hot bleed air with just enough cold ACM air to bring the temperature down to 200-250 degrees fahrenheit.
Does this answer your question?
I get it, but I am asking about times when the ACM overheats and all we get is the bleed air from EMER source
@@romanmandeleil In the case of the EMER pressure source, there is no way to regulate cabin temp. It's hot bleed air coming straight into the cabin. The only way to manage cabin temp under this circumstance is to reduce the power on the left engine, thereby reducing bleed air volume, or by descending to a low enough altitude to not need the pressurization system and turn the pressurization system off entirely by selecting a pressurization source of OFF.
Do you have any experience of something like that? It sounds very scary to push hot bleed air directly into the cabin. What temperature range are we talking about while regulating with left throttle?
@@romanmandeleil I've never had to deal with that situation for long. The most common reason for the ACM to shutdown is an overheat situation when basically the internal components of the ACM are too hot and it shuts down to protect itself. EMER pressurization automatically activates. All the pilot needs to do is give the ACM a few seconds to cool down, select a warmer cabin temp to prevent the ACM from overheating again, and reset the system. So EMER pressurization is only on for thirty seconds or so, at most.
It definitely gets warmer in the cabin, but it's not terrible. Think of sitting in a car without the air conditioner working on a warm day. It's not the most comfortable, but a pilot can still get the job done.