| Re: difference between 29000 & 39000 |
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Group: aus.aviation · Group Profile
Author: Stealth PilotStealth Pilot Date: Jul 27, 2008 04:25
On Sun, 27 Jul 2008 18:21:43 +1000, "John Ewing" wrote:
>
>"BernieFlyer" gmail.com> wrote in message
>news:X4-dnYXfQbF1vBHVnZ2dnUVZ_u-dnZ2d@westnet.com.au...>> RMK wrote:
>>>> one for the boffins and arm chair boffins on here
>>>>
>>>>
>>>> Would the damage potential have been greater/ the same/or less to
>>>> an aircraft in similar circumstances at a higher altitude ? To the
>>>> recent QF incident
>>>>
>>>>
>>>> for discussion
>>>
>>> The aircraft is pressurized to it's maximum pressure differential as it
>>> climbs (approx 8.9psi).
>>>
>>> So it's the same regardless of whether you are at 29000'or 45000'.
>>>
>>> The only 'danger' is that the higher you are, the longer it takes to get
>>> down to
>>> a safe level if you lose cabin pressure.
>>
>>
>> I hear what you say but if its unsafe to be above 10,000 without
>> additional oxygen then surely to keep the cabin sufficiently liveable you
>> would not want to have unsafe levels (ie 10,000ft) above that height.
>> Surely this means that the cabin must be under constantly increasing
>> pressure as you climb? Maybe I need to go to school again.
>>
>> You started something here Phil!!
>
>Bernie - the cabin altitude is kept between 0 and 6,000ft. When travelling
>on a pressurised aircraft you should not experience any more breathing
>difficulties than you would on top of a 6,000ft mountain.
>And yes the pressure differential on the skin of the aircraft does increase
>with increasing altitude.
>Obviously 6,000ft has been chosen as an altitude that will have minimal
>effect on people, excepting those with serious illnesses or respiratory
>problems.
>
>Cheers,
>John
>
you need to update those figures mate.
an obese person will have breathing difficulties above 8,000ft so that
is what sets the value. the physiology of the typical obese person.
I was checking a WW1 insensitive altimeter on a flight once and asked
the hostie what the cabin pressure was. the curio value got the better
of the crew and I got an invite up to the cockpit for the rest of the
flight to Brisbane. The cabin altitude was set to 8,250ft which oddly
was the exact height this old altimeter was reading.
That cabin pressure is maintained at altitudes above 8,250ft so as you
go higher the pressure differential across the hull skin increases
with altitude, so although Rob posts with great certainty (and
brevity) he got it totally wrong.
Stealth Pilot
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