Is the cargo compartment in a passenger jet also pressurized?

I think pressurizing the insides of high-altitude flying jets is costly. So I am wondering if the cargoes are left exposed to high altitude low pressure or not.Is the cargo compartment in a passenger jet also pressurized?
Yes, the cargo compartment is pressurized the same as the passenger cabin. In modern commercial aircraft, the engines provide compressed air that is used to power the air conditioning systems. Some of the air entering the cabin has actually been through part of the engine. The air from this air conditioning system enters the passenger cabin through vents above the seats, and in some cases through vents along the ceiling panels. The air then leaves the passenger cabin through the vents at the bottom of the sidewall panels. That air then flows down between the air craft skin and the sidewall panels of the cargo compartment. Then the air leaves the aircraft through the outflow valve, which can be modulated for controlling the rate of flow of the air. As the valve is moved towards the closed position, the aircraft's internal pressure will rise. As this valve changes its position at various times through the flight, air is always leaving the aircraft, to allow fresher air to enter. If only the passenger cabin were pressurized, the floor would not easily maintain its flat state, as the excessive pressure difference would push the floor down. Ever see a balloon with a flat side? Equal pressure distribution will not allow that.





Interesting thing that passengers never see is what we call the p-dome, or pressure dome. If you were to walk to the back of a Boeing 767, and there were no lavs or galleys there, you would see a giant dome. Imagine the aircraft is one of those long balloons that clowns shape into animals. The end is rounded. This disperses the pressure. Ever look at the bottom of an aerosol paint can? There is a reason it isn't flatIs the cargo compartment in a passenger jet also pressurized?
on pressurized a/c, the cargo compartment must be pressurized. On most passenger airlines you would see DADO panels on the sidewalls near the floor. Its job is to equalize the pressure bwtween the passenger compartment and cargo compartment. It prevents damage to floor structure due to pressure differential(prevents the floor and passenger from falling into cargo compartment). There was an incident long ago involving a DC10 where the cabin floor collapsed and dropped to cargo compartment because of pressure difference between the pax comp and cargo compt.
Yes, the cargo compartment is part of the pressure hull and is pressurized just as the passenger cabin is. There is no additional cost involved in keeping the cargo compartment pressurized; in fact, it makes the design of the pressure hull simpler.





In some aircraft, the cargo hold is also heated, but not always.
Most of them are.


There are enough passages (lightening holes, pass-throughs for wiring, piping, etc) for the pressure to pass into the cargo compartment.


HOWEVER, not all cargo compartments are heated. (American Airlines was one of the few we built that had heating ducts to heat the cargo compartment.
A ';passenger jet'; means one that is not used only for cargo. So, that covers a lot of different types. In most private jets, the ';external'; baggage compartments are not pressurized. (';External'; means not in the cabin and not accessible from inside the cabin.)
Apparently they are. A baggage handler went to sleep in one loading baggage in NY and wound up in Boston. The news article can be found here:





http://www.bradenton.com/news/breaking_n…
Usually, but it's not always heated. That's why you have to put live animals only in a certain bin, or they will freeze to death.
Well whole aircraft is pressurized ......
i think so. After all they put animals in cargo sections.
Yes, they are...