Sponsor Message:
Aviation Technical / Operations Forum
My Starred Topics | Profile | New Topic | Forum Index | Help | Search 
Pressurization In Cargo Planes?  
User currently offlinepeteschiller From United States of America, joined Feb 2010, 42 posts, RR: 0
Posted (4 years 7 months 3 days 20 hours ago) and read 15967 times:

Think it's a simple question, but can't find the answer anywhere: are cargo freighters pressurized?

I speculate that a cargo plane with an enormous door that swings shut from the outside would not be pressurized. BUT, then again, that would mean that the cockpit would have to be sealed off from the rest of the plane with a bulkhead, and it's not, right? Further, UAL 811 lost its cargo door due to a "pressure differential": http://en.wikipedia.org/wiki/United_Airlines_Flight_811

25 replies: All unread, showing first 25:
 
User currently offline474218 From United States of America, joined Oct 2005, 6340 posts, RR: 9
Reply 1, posted (4 years 7 months 3 days 20 hours ago) and read 15957 times:

Quoting peteschiller (Thread starter):
are cargo freighters pressurized?


Yes, just like passenger aircraft.


User currently offlinefr8mech From United States of America, joined Sep 2005, 5660 posts, RR: 15
Reply 2, posted (4 years 7 months 3 days 20 hours ago) and read 15955 times:

Cargo aircraft are pressurized, just like their passenger counterparts.


When seconds count...the police are minutes away.
User currently offlineAirTran737 From United States of America, joined Apr 2004, 3708 posts, RR: 12
Reply 3, posted (4 years 7 months 3 days 18 hours ago) and read 15902 times:
Support Airliners.net - become a First Class Member!

They are fully pressurized. Most freighters have a curtain barrier, so the entire thing has to be pressurized. Plus, there's nothing like taking a bottle of oxygen in the back and sleeping on an empty pallet.


Nice Trip Report!!! Great Pics, thanks for posting!!!! B747Forever
User currently offlineflybaurlax From United States of America, joined Oct 2008, 638 posts, RR: 0
Reply 4, posted (4 years 7 months 3 days 15 hours ago) and read 15834 times:

When C-17s do airdrops at higher altitudes the crew have to suck the hose so they can depressurize and open the door.


Boilerup! Go Purdue!
User currently offlineBraniff747SP From United States of America, joined Oct 2008, 3016 posts, RR: 1
Reply 5, posted (4 years 7 months 3 days 13 hours ago) and read 15770 times:

Normal freighters a pressurised, but I believe Airbus' Beluga is not.


The 747 will always be the TRUE queen of the skies!
User currently offlineCCA From Hong Kong, joined Oct 2002, 846 posts, RR: 14
Reply 6, posted (4 years 7 months 3 days 12 hours ago) and read 15752 times:

Quoting Braniff747SP (Reply 5):
Normal freighters a pressurised, but I believe Airbus' Beluga is not.

The Cockpit of the beluga is pressurised similar to the 747LCF which has a pressure bulkhead at STA520 making section 41 the pressurised area.



C152 G115 TB10 CAP10 SR-22 Be76 PA-34 NDN-1T C500 A330-300 A340-300 -600 B747-200F -200SF -400 -400F -400BCF -400ERF -8F
User currently offlineAA737-823 From United States of America, joined Mar 2000, 5947 posts, RR: 11
Reply 7, posted (4 years 7 months 3 days 10 hours ago) and read 15711 times:

You have to keep in mind that PRESSURIZATION and TEMPERATURE CONTROL go hand-in-hand.
The heat comes off of the engine bleeds, through the AC Packs, and into the cabin. It is then 'bottled up' by the outflow valve, which prevents it from escaping willy-nilly.
So, since we typically want our freight heated (particularly when there is live freight on board, which happens much more often than people imagine), we must run the packs and outflow valve(s) in such a manner that will keep the plane at a safe temperature.
Heat aside, any animals (I've seen frogs, ferrets, turtles, cats, dogs, horses galore, and more) will definitely need breathable atmosphere!

So yes, generally speaking, pressurized.

Regarding the large doors (I'm surprised you didn't consider the 747-400M that KLM and others fly- large cargo door in the passenger cabin... still definitely pressurized!), there are very sturdy locking mechanisms involved in closing these doors. Typically, they work great.


User currently offlineHAWK21M From India, joined Jan 2001, 31712 posts, RR: 56
Reply 8, posted (4 years 7 months 3 days 9 hours ago) and read 15702 times:

Cargo Aircraft are pressurized like other Commercial Aircraft.
Only to add some do have a Seperation barrier from the Flight deck to the Main deck in case of a fire,so Airflow can be shut to the zone where the fire exists in enabling supression of the fire.
regds
MEL.



Think of the brighter side!
User currently offlineCosmicCruiser From United States of America, joined Feb 2005, 2255 posts, RR: 15
Reply 9, posted (4 years 7 months 3 days 6 hours ago) and read 15632 times:

Quoting HAWK21M (Reply 8):
Only to add some do have a Seperation barrier from the Flight deck to the Main deck in case of a fire,so Airflow can be shut to the zone where the fire exists in enabling supression of the fire.

In ours the barrier/curtain is only for smoke control. It is not airtight per se. Fire control is done by sutting off the air to the main cabin. We also are now installing a fire suppression system that can actually detect the hot can, thrust a nozzle into it and shoot it full of suppressant.


User currently offlineTF39 From United States of America, joined Jul 2006, 110 posts, RR: 0
Reply 10, posted (4 years 7 months 2 days 16 hours ago) and read 15311 times:

I was just reading (Antonov's Heavy Transports) that the AN-124 ensures a pressure differential of 7.82 PSI for both upper cabins but 3.57 PSI in the cargo hold.

User currently offline113312 From United States of America, joined Apr 2005, 576 posts, RR: 1
Reply 11, posted (4 years 7 months 2 days 16 hours ago) and read 15309 times:

Many of the old DC-6 cargo planes deactivated pressurization systems but, of course, that results in their being restricted to flying at low altitudes. Cargo jets are just the same as any other airliner. Security of cargo doors is very important!

User currently offlineHAWK21M From India, joined Jan 2001, 31712 posts, RR: 56
Reply 12, posted (4 years 7 months 2 days 11 hours ago) and read 15219 times:

Quoting CosmicCruiser (Reply 9):
It is not airtight per se. Fire control is done by sutting off the air to the main cabin

If its not Airtight,How would you stop Oxygen reaching the flames in case of a fire,as the MOV shutoff will not serve the purpose,as there is no Fire Extinguisher Installed.
The Fire is Extinguished by Starvation of Oxygen to the area.

regds
MEL.



Think of the brighter side!
User currently offlineMD11Engineer From Germany, joined Oct 2003, 14140 posts, RR: 62
Reply 13, posted (4 years 7 months 2 days 10 hours ago) and read 15207 times:

Quoting HAWK21M (Reply 12):
Quoting CosmicCruiser (Reply 9):
It is not airtight per se. Fire control is done by sutting off the air to the main cabin

If its not Airtight,How would you stop Oxygen reaching the flames in case of a fire,as the MOV shutoff will not serve the purpose,as there is no Fire Extinguisher Installed.
The Fire is Extinguished by Starvation of Oxygen to the area.

regds
MEL.

The crew will don oxygen masks and depressurize the cabin. At 30.000 ft this will do the job.
Generally cargo planes, which derived from passenger aircraft, are fully pressurized. Some dedicated cargo aircraft, like the AN-124, only have the crew sections pressurized.

Jan


User currently offlineCosmicCruiser From United States of America, joined Feb 2005, 2255 posts, RR: 15
Reply 14, posted (4 years 7 months 2 days ago) and read 15002 times:

Quoting HAWK21M (Reply 12):
If its not Airtight,How would you stop Oxygen reaching the flames in case of a fire,as the MOV shutoff will not serve the purpose,as there is no Fire Extinguisher Installed.

AS MD11Mechanic said we shut off the air to the cabin, not the cockpit, and manually raise the cab alt to 25,000'. The crew will be on O2 and the fire should die. We have fire ext. for the haz containers and some now have the new FSS Fire Suppression System. This procedure worked perfect on our DC-10 a few yrs ago that landed in Stewart NY with a cargo fire. The fire was suppressed until they opened the cargo door on the grd. then it flared up and the plane burned.


User currently offlineremcor From United States of America, joined Feb 2006, 358 posts, RR: 0
Reply 15, posted (3 years 11 months 1 week 5 days 19 hours ago) and read 13433 times:

Bringing back this 6 year old post because one question wasn't answered.

It seems that most cargo aircraft do indeed have pressurized holds, however... do they pressurize them to the same level as passenger aircraft?

For instance, perhaps a 77W is kept pressurized to a 7000' level (FAA mandates 8000' or less), but the 777F might be kept pressurized at a 10000' level. The (hypothetical) advantage for the carrier is that is causes less stress on the airframe, reducing maintenance.

Someone at my company asked me a cabin pressure question for a highly complex instrument we're planning to ship and it got me thinking. Anyone have a clue to whether a cargo craft will be kept pressurized at the same level as a similar passenger aircraft?


User currently offlineDH106 From United Kingdom, joined Jun 2005, 626 posts, RR: 1
Reply 16, posted (3 years 11 months 1 week 5 days 11 hours ago) and read 13329 times:

Quoting HAWK21M (Reply 8):
Cargo Aircraft are pressurized like other Commercial Aircraft.

How about older vintage aircraft like the C-130, An-12 - I didn't think they were pressurised ?



...I watched c-beams glitter in the dark near the Tanhauser Gate....
User currently offlinebrenintw From Taiwan, joined Jul 2006, 1723 posts, RR: 1
Reply 17, posted (3 years 11 months 1 week 5 days 11 hours ago) and read 13321 times:

Quoting remcor (Reply 15):
For instance, perhaps a 77W is kept pressurized to a 7000' level (FAA mandates 8000' or less), but the 777F might be kept pressurized at a 10000' level. The (hypothetical) advantage for the carrier is that is causes less stress on the airframe, reducing maintenance.


If you don't have differential pressurization, you're going to have pilots who aren't going to be happy flying an aircraft that is constantly trying to starve them of oxygen -- and I don't think the relief crew will like having to cart an oxygen bottle with them everywhere. A cabin altitude of 10,000' may be safe for short periods of time -- for a flight of a good few hours, hypoxia is going to set in, which will lead to errors being made and planes crashed.

I would imagine that differential pressurization like that would require a bulkhead of some sort between the cockpit/crew areas and the rest of the plane. That adds weight and complexity to the aircraft.

Now, I've never been on a 777F, I have been on a 744F. There was direct access between the upper deck and the cargo hold. It wasn't air-tight, so the crew area would be the same pressure as the hold.

Cargo aircraft that are derived from passenger aircraft will normally have the same climate control system as the PAX equivalent -- it reduces development and certification costs to keep an existing system. So, it stands to reason that they would be pressurized to the same altitude as the PAX equivalents.



I'm tired of the A vs. B sniping. Neither make planes that shed wings randomly!
User currently offlineoly720man From United Kingdom, joined May 2004, 6848 posts, RR: 11
Reply 18, posted (3 years 11 months 1 week 5 days 9 hours ago) and read 13294 times:

Quoting DH106 (Reply 16):
How about older vintage aircraft like the C-130, An-12 - I didn't think they were pressurised ?

C-130 is the An12 isn't, but the Chinese An-12, the Y-8, is pressurised according to this

http://forum.keypublishing.co.uk/archive/index.php?t-22738.html



wheat and dairy can screw up your brain
User currently offlinefr8mech From United States of America, joined Sep 2005, 5660 posts, RR: 15
Reply 19, posted (3 years 11 months 1 week 4 days 23 hours ago) and read 13153 times:

Quoting remcor (Reply 15):
It seems that most cargo aircraft do indeed have pressurized holds, however... do they pressurize them to the same level as passenger aircraft?

Yes, they are pressurized to the same level or PSID. I recall that the classic jumbos had a different schedule, but the end result was the same...about an 8000' cabin.

I will add the proviso that this is on aircraft that I'm familiar with. There may be others that do have a different end result.



When seconds count...the police are minutes away.
User currently offlineKELPkid From United States of America, joined Nov 2005, 6428 posts, RR: 3
Reply 20, posted (3 years 11 months 1 week 4 days 14 hours ago) and read 13028 times:

Quoting MD11Engineer (Reply 13):
Generally cargo planes, which derived from passenger aircraft, are fully pressurized. Some dedicated cargo aircraft, like the AN-124, only have the crew sections pressurized.

Most US designs feature a pressurized cargo deck. This is because they are designed for medivac and troop transport roles as well as transporting equipment.



Celebrating the birth of KELPkidJR on August 5, 2009 :-)
User currently offlineA380900 From France, joined Dec 2003, 1118 posts, RR: 1
Reply 21, posted (3 years 11 months 1 week 2 days 17 hours ago) and read 12843 times:

Quoting KELPkid (Reply 20):
Quoting MD11Engineer (Reply 13):
Generally cargo planes, which derived from passenger aircraft, are fully pressurized. Some dedicated cargo aircraft, like the AN-124, only have the crew sections pressurized.

So that means the AN225 is not fully pressurized either. It seems to restrict the type of cargo quite a bit. Can they guarantee +0° C temperatures at least?


User currently offlinec5load From United States of America, joined Sep 2008, 917 posts, RR: 0
Reply 22, posted (3 years 11 months 1 week 2 days 17 hours ago) and read 12825 times:

Quoting MD11Engineer (Reply 13):
Generally cargo planes, which derived from passenger aircraft, are fully pressurized. Some dedicated cargo aircraft, like the AN-124, only have the crew sections pressurized.

The C-5 is fully pressurized. However, that may be due to the fact that when Lockheed manufactured it, there were palletized seat kits that could be installed in the cargo box.

Quoting peteschiller (Thread starter):
I speculate that a cargo plane with an enormous door that swings shut from the outside would not be pressurized.

Our entire nose swings open, wouldn't that be considered a large door? But, we do have large bayonet locks that hold that thing in place.



"But this airplane has 4 engines, it's an entirely different kind of flying! Altogether"
User currently offlineHAWK21M From India, joined Jan 2001, 31712 posts, RR: 56
Reply 23, posted (3 years 11 months 1 week 2 days 8 hours ago) and read 12727 times:

Is the LCF Main deck Pressurized.....?.


Think of the brighter side!
User currently offlinejetlagged From United Kingdom, joined Jan 2005, 2577 posts, RR: 25
Reply 24, posted (3 years 11 months 1 week 2 days 8 hours ago) and read 12720 times:

Quoting remcor (Reply 15):
It seems that most cargo aircraft do indeed have pressurized holds, however... do they pressurize them to the same level as passenger aircraft?

747 Classic freighters can have a different pressurisation schedule to passenger versions. This allows a higher cruise cabin altitude. I can't remember the exact difference but it was something around 1000 feet higher for a typical cruise flight level.

The aircraft used the same pressure control panel, but the cruise altitude select window has two scales, one for cargo and one for pax. One or other scale is covered by a screw-on metal plate so only the appropriate one is visible.

[Edited 2011-01-23 03:49:03]


The glass isn't half empty, or half full, it's twice as big as it needs to be.
User currently offlineStarlionblue From Greenland, joined Feb 2004, 17186 posts, RR: 66
Reply 25, posted (3 years 11 months 1 week 2 days 7 hours ago) and read 12704 times:

Quoting HAWK21M (Reply 23):
Is the LCF Main deck Pressurized.....?.

Nope.



"There are no stupid questions, but there are a lot of inquisitive idiots."
Top Of Page
Forum Index

Reply To This Topic Pressurization In Cargo Planes?
Username:
No username? Sign up now!
Password: 


Forgot Password? Be reminded.
Remember me on this computer (uses cookies)
  • Tech/Ops related posts only!
  • Not Tech/Ops related? Use the other forums
  • No adverts of any kind. This includes web pages.
  • No hostile language or criticizing of others.
  • Do not post copyright protected material.
  • Use relevant and describing topics.
  • Check if your post already been discussed.
  • Check your spelling!
  • DETAILED RULES
Add Images Add SmiliesPosting Help

Please check your spelling (press "Check Spelling" above)


Similar topics:More similar topics...
Are There Toilets On Cargo Planes? posted Thu May 1 2008 08:26:51 by Checkraiser
Pressurization In Aircraft posted Mon Feb 12 2007 04:53:34 by LoveASE
Typical Cargo On Cargo Planes posted Tue Sep 19 2006 18:53:17 by HKA
Why Are Cargo Planes More Expensive? posted Sat Sep 16 2006 22:24:46 by Fly707
Fire Alarms In Cargo/baggage Area - What To Do? posted Thu May 4 2006 15:22:35 by JulianUK
Small Cargo Planes For Large Aircraft Flights posted Sun Apr 23 2006 10:33:50 by QFA380
Cargo Planes Payload Vs Fuel? posted Tue Mar 14 2006 10:35:59 by Pavlin
Low Cost Cargo Planes? posted Sun Jan 16 2005 11:26:33 by Fly707
Animals In Cargo posted Sun Jan 6 2002 04:42:17 by Lubcha132
Your Way Of Avoiding Airsickness In Small Planes posted Fri Dec 28 2001 03:21:35 by Sushka

Sponsor Message:
Printer friendly format