FLY2HMO From , joined Dec 1969, posts, RR: Reply 1, posted (3 years 4 months 3 weeks 6 days 6 hours ago) and read 1789 times:
I *think* both airbii planes you mentioned are conventional.
One thing I know for sure is that the article mentioning the whole "cabin toxicity" thing is a hoax. Average aircraft cabins get completely new air every 15 minutes or some, doesn't get cleaner than that.
Mir From United States of America, joined Jan 2004, 19707 posts, RR: 56 Reply 2, posted (3 years 4 months 3 weeks 6 days 5 hours ago) and read 1776 times:
The 380 still has conventional engine bleeds - not sure about the 350.
-Mir
7 billion, one nation, imagination...it's a beautiful day
747classic From Netherlands, joined Aug 2009, 1783 posts, RR: 11 Reply 4, posted (3 years 4 months 3 weeks 6 days ago) and read 1739 times:
B-787 only uses "bleedless"engines.
The air-conditioning system will not take bleed air from the engines. Rather, four large electrically driven air compressors will feed ambient air to the air-conditioning packs. Boeing engineers believe this system has a number of advantages to siphoning inlet air off the engines.
First, the engines will be more efficient, as all air sucked into them will contribute to thrust. Also, oil and other contaminants will not be sucked into a bleed air system, thus eliminating engine-related fumes in the cabin. By foregoing bleed air, leaks in hot duct work are avoided. And finally, Boeing engineers regard the electrically-driven air compressors as more reliable.
The compressors are independently monitored, however; and Hale said they "swap out as a unit." With four compressor motors, one can be off-line until repaired or replaced, and the airplane can continue flying, relying on the remaining three for necessary redundancy.
Both A-380 and future A-350XWB use a conventional pneumatic system to deliver bleed air to the airconditioning system.
The 747-8 uses the "proven"pneumatic bleed system from the 747-100/200/300/400 series to power the 3 airconditioning packs..
Tdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80 Reply 7, posted (3 years 4 months 3 weeks 5 days 2 hours ago) and read 1617 times:
Quoting HAWK21M (Reply 6): If So.What capacity is the Four Air driven compressors & any details on the Airflow provided.Would Two u/s compressors be a NO GO.
Airflow rate is pretty much pinned down by FAR's and smoke evacuation requirements...I don't have those on the top of my head, but it's going to get certified so you can easily figure out the lower boundary. And, since it's ETOPS certified, it should be able to do it on a single engine, although with all electric power you could theoretically run all four compressors on one engine.
I suspect two dead compressors would be no-dispatch, but you could continue flying with it if it happened in flight.
747classic From Netherlands, joined Aug 2009, 1783 posts, RR: 11 Reply 8, posted (3 years 4 months 3 weeks 5 days 1 hour ago) and read 1611 times:
Quoting HAWK21M (Reply 6): If So.What capacity is the Four Air driven compressors & any details on the Airflow provided.Would Two u/s compressors be a NO GO.
This is one of the things, that has to be approved during testing of the 787.
All items in the MEL have to be checked or demonstrated to the authorities.
Personally I think one compressor U/S will be a dispatch item.
Two U/S will be a NOGO or departure with no passengers or severe passenger number limitations.
But all above is only speculation, because no (provisional) 787-MEL is published, as far as i know.
Minimum Equipment List.
A Document containing units & systems that may be Inoperative for a limited period of time without adversly affecting the safety & airworthiness of the Aircraft.
HAWK21M From India, joined Jan 2001, 31201 posts, RR: 58 Reply 13, posted (3 years 4 months 3 weeks 3 days 2 hours ago) and read 1434 times:
Quoting Tod (Reply 12):
"the ventilation system must be designed to provide each occupant with an airflow containing at least 0.55 pounds of fresh air per minute."
Exactly....So the Air compressors on the B787 will need to cater to minimum 0.55lbs/min fresh airflow.
regds
MEL.
Tdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80 Reply 14, posted (3 years 4 months 3 weeks 2 days 15 hours ago) and read 1396 times:
Quoting HAWK21M (Reply 13): Exactly....So the Air compressors on the B787 will need to cater to minimum 0.55lbs/min fresh airflow.
Actually, it's some subset of the compressors. I don't know what the exact failure conditions and MEL relief will be but, if we assume you can dispatch with one compressor inop, then you'd have to get 0.55 lbs/min/person from 3 compressors.
Readytotaxi From United Kingdom, joined Dec 2006, 2596 posts, RR: 3 Reply 15, posted (3 years 4 months 3 weeks 2 days 13 hours ago) and read 1386 times:
Tdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80 Reply 16, posted (3 years 4 months 3 weeks 2 days 8 hours ago) and read 1358 times:
Quoting Readytotaxi (Reply 15): So if the bloke next to me has flu I will not get next time the air comes round?
Typically not. The flu virus isn't particularly durable when airborne; I think it can only live in droplets. Droplets are easily caught by HEPA filters, and they evaporate fast (airliner air is pretty dry, even with recirculation).
You're way (way way way) more likely to get sick from surface contact that a lot of other people have touched (lavatory sinks, tray tables, etc.) than recirculated air.
Readytotaxi From United Kingdom, joined Dec 2006, 2596 posts, RR: 3 Reply 17, posted (3 years 4 months 3 weeks 1 day 14 hours ago) and read 1310 times:
Quoting Tdscanuck (Reply 16): You're way (way way way) more likely to get sick from surface contact that a lot of other people have touched (lavatory sinks, tray tables, etc.) than recirculated air.
You just made air travel so much more romantic.
you don't get a second chance to make a first impression!
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