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Old January 7th 04, 12:05 AM
running with scissors
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"khobar" wrote in message news:QLDKb.17987$7D3.1116@fed1read02...
running with scissors wrote in
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"khobar" wrote in message

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running with scissors wrote

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"John Gilmer" wrote in message

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"Bob Gardner" wrote in message
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No way. You start off at sea level, of course, and they pump the

chamber
pressure down to 25000 feet with masks on...then they do some

experiments
with a few of the pilots taking their masks off, just to show how

severely
their abilities are affected. Then comes the explosive

decompression,
which
takes the chamber from 25K back down to sea level in a second or

two.

SIlly question but ...

Why would "they" pressurize the aircraft to sea level? Why not

some
compromise "pressure" like that equivalent to, say, 6,000 or 8,000

feet?


EMWTK

"they" dont. cabin pressurization is normally at 8000ft though crew
may elect to use different cabin pressures under certain circumstances
(eg medevac operations where pressurization is a factor)

Sec. 25.1 Applicability.

(a) This part prescribes airworthiness standards for the issue of type
certificates, and changes to those certificates, for transport category
airplanes.

http://www.astech-engineering.com/sy...apart25d.html#
Pressurization

Sec. 25.841 Pressurized cabins.

"(a) Pressurized cabins and compartments to be occupied must be equipped

to
provide a cabin pressure altitude of not more than 8,000 feet at the

maximum
operating altitude of the airplane under normal operating conditions."

Transport category:

* All jets with 10 or more seats or greater than 12,500lb Maximum
Takeoff Weight.
* All propeller driven airplanes with greater than 19 seats or

greater
than 19,000lb Maximum Takeoff Weight.


Obviously the rule would not normlly apply to Medivac operations.

HTH,

Paul Nixon


medevac ops are not exempt. though under certain medical conditions
the cabin my not be pressurized or pressurized to a lower altitude.
nitrogen narcosis is one condition that springs to mind.


I was thinking about medivac helicopters. Dunno why since medivac goes
beyond helicopter operations. Oh well...

Paul Nixon



pressurized heli ?