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A320 Pressurization 'peaks' cause damage to body? (packless tkof)

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A320 Pressurization 'peaks' cause damage to body? (packless tkof)

Old 28th Jun 2013, 09:13
  #21 (permalink)  
Join Date: Mar 2007
Location: Another Planet.
Posts: 562

Wearing my beancounter/management hat I have the following suggestion:

1) Both packs OFF til 10,000 ft, that should save a kg of fuel or two, whilst taking the strain off the engines IAW power-by-the-hour or wotever.

2) First pack ON @ 10,000 ft, this would avoid the erroneoues flap retraction risk as by then I'd hope they were safely tucked away. The reduced air density would lessen the "submarine" effect compared with sea level compression.

3) Second pack on at 25,000 ft, save more kgs of fuel and protect against the effects of losing the 1st pack, 1 pack flight up to FL250 apparently OK according to DDGs various.

4) One pack off in descent through FL250, save fuel and pack wear and tear, maybe swop which pack like engine ignitors to even out the wear and increase the chances of both failing at the same time, just like the ignitors did on me years ago.

5) Leave the remaining pack ON til touchdown as a gesture to the SLF that we really do care about their comfort.

Another advantage of the reduced packs climb is it would accelerate the expulsion of gases from the body cavities of both SLF and crew, clearing the mucus from the sinuses and blowing the plugs out of the eustacion tubes, thereby making for an easier and less painful descent.

Should any airline management adopt these procedures, I will of course expect a cut of the savings which could be considrable?!
BARKINGMAD is offline  
Old 28th Jun 2013, 09:42
  #22 (permalink)  
Join Date: Jul 2000
Location: On the approach to EGLL
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"Packs off is the manufacturer's SOP. (In Airbus' case anyway.)"

If you review the Airbus A318/319/320/321 FCOM Section PRO-NOR-SOP -11 P 1/2, you will see that the above comment is incorrect!

The Airbus Pack procedure as listed in the SOP - "Before takeoff" is: Packs 1 and 2 ....... AS REQD
Preppy is offline  
Old 28th Jun 2013, 10:34
  #23 (permalink)  
Join Date: Jun 1999
Location: Queensland
Posts: 394
If airbus design life and inspection schedules are based on a say 75% packs on and 25% pack off take-offs, and operators ask us to make 100% packs off take-offs, there is the seed of a doubt re this as a lifetime procedure for these aircraft.
Hard to think that it is serious in the short term, and most of these operators will no longer lease them when these aircraft are near the end of their life. So why should they care?
autoflight is offline  
Old 28th Jun 2013, 11:09
  #24 (permalink)  
Join Date: Apr 2005
Location: "this is where the magic happens"
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If airbus design life and inspection schedules are based on a say 75% packs on and 25% pack off take-offs, and operators ask us to make 100% packs off take-offs, there is the seed of a doubt re this as a lifetime procedure for these aircraft.
Don't forget bleed air extraction during take off (if packs ON) and thus a higher thrust rating needed for take off and thus higher fuel consumption, higher EGT and higher engine wear etc.

Pilots with ear problems can be replaced by cheaper P4T/P2F pilots, but engines, maintenance and fuel still cost money.
Bokkenrijder is offline  
Old 28th Jun 2013, 11:57
  #25 (permalink)  
Join Date: Apr 2003
Location: Europe
Posts: 2,995
As mentioned in post 28 above, if you are worried about a momentary peak of 1000 fpm, DO NOT EVER GO FOR A SWIM IN A POOL. Snorkeling would sure be lethal! Even taking a bath or an elevator ride will have serious consequences to your health. DO NOT BLOW YOUR NOSE. Do not sneeze. And if you hear a loud noise, don't cover your ears! Don't burp. Don't fart. Don't laugh. Don't speak to your wife. These could all induce +/-1000 fpm pressure chances!!

And as for SCUBA, has anyone ever survived that?
PENKO is offline  
Old 28th Jun 2013, 13:18
  #26 (permalink)  
Join Date: Feb 2008
Location: USA
Posts: 35
1000 fpm?

Years ago a relative of mine worked in the World Trade Center tower #1 (fortunately he changed jobs before that bad day). He and a whole lot of other fellow office workers used to do 1000 feet in a minute in the elevator everyday - no big deal.
Orestes is offline  
Old 28th Jun 2013, 15:36
  #27 (permalink)  
Join Date: Jan 2013
Location: Austria
Posts: 13
2) Is the Automatic Pressure Control Mode doing it's work correct when "Packs Off" tkof is used?
I am asking this because I noticed on our aircraft a very high v/s (-1000ft) of cabin rate after the first pack is switched on.
During the early climb the pressure controller is expected to limit the cabin climb rate. If instead a cabin descent is initiated I'd agree with you that there is something wrong. A fast cabin descent during a/c climb would only be necessary if you switch on the packs very late above lets say 10.000 ft.
Higher for hire is offline  
Old 28th Jun 2013, 20:06
  #28 (permalink)  
Join Date: Nov 2007
Location: United Kingdom
Age: 67
Posts: 710
God... give me strength! Button-pushing pilots of today most certainly do need some re-education.
TheChitterneFlyer is offline  
Old 28th Jun 2013, 23:08
  #29 (permalink)  
Join Date: Jan 2012
Location: Not far from the edge of the Milky Way Galaxy in the Orion Arm.
Posts: 510
PH chucky We put one back on and then the other.

Ocean crosser By doing this we save on fuel (multiply by how many sectors in a week x 52 weeks) over a year this adds up!
Also - if the engine manufacturers lease the engines then they probably have a stipulation in the contract, that demands packs off until x,000 ft.
Natstrackalpha is offline  
Old 3rd Jul 2013, 17:49
  #30 (permalink)  
Join Date: Nov 1999
Location: UK
Posts: 1,387
I'm probably being dense here, but how can switching the packs back on at thrust reduction altitude cause an early retraction of flaps/slats???

Packs off T/O is SOP with us. It saves fuel - Pax want the cheapest fare; QED.

I didn't know about the pressure strengthening the fuselage, but surely at take off there is not much differential pressure, so this effect will be minimal near the ground?
Uplinker is offline  
Old 6th Jul 2013, 09:43
  #31 (permalink)  
Join Date: Apr 2008
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aviatorhi is offline  

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