From: Randall Young <ryoung@navcomtech.com>
Copies to: Triumph list <triumphs@autox.team.net>
Subject: RE: Altitude & VTR2001
Date sent: Thu, 17 Aug 2000 14:22:15 -0700
Organization: Navcom Tech, Inc
Send reply to: Randall Young <ryoung@navcomtech.com>
On Thursday, August 17, 2000 2:04 PM, Michael Cline
[SMTP:mcline@substrates.com] wrote:
> Actually someone once told me commercial
> passenger jets are pressurized to 5,000'. Yes? No? Any pilots out there?
I believe it varies with airline, and how stingy they are trying to be. They
used to pressurize to 8000 feet, but I believe many only go to 15000 feet
today.
I'm not a pilot (yet), but the pressure changes used to cause me severe
discomfort when traveling so I used to ask about cabin pressure. Now, I've
both got the inner ear problem solved, and switched to a job that doesn't
require gallivanting about the world <g>
Randall
Sorry to interrupt, but in this case we should speek about elevation.
Altitude is the distance between the ground and an object in the air.
In aviation terms you express the distance between an aircraft and
surface in altitude,between an aircraft and the pressure reference
of 1013 hp or 2992 inch/merc in flight level.
Concerning cabin pressurization, this is in relation to the flown
altitude but will never exceed 9000ft. B767/757 etc operate these
days at cruising altitudes of 39000 to 45000 ft depending on
weight. Concorde was designed to operate on cruise/climb, the
aircraft climbed as fuel was burned and weight decreased ,but for
them there was very little oncoming traffic above 60000 ft. Pressure
itself is not the problem,but oxygen is,because the amount
decreases with altitude or elevation.The policy how aircraft are
pressurized is built in by the manufacturer on requirements of
FAA.On older jets, on climb or descend, the rate of cabin pressure
changes is set by pilots,and it goes without saying that lousy
pilots can create quite some discomfort to their passengers.
Chewing gum largely helps to pressurize the inner ear.Many of you
driving in mountain areas will have noticed the same symtoms
when driving downhill where you are suffering a rapid increase of
pressure.Concerning cars, in European mountain areas cars are
often fitted with baromatric controlled carburettors to adapt fuel flow
to elevation. Electronic fuel injection systems are fitted with a
capsule that provides the computer with pressure information.
So beside the cars ,there should be no problem when going to VTR
2001 just don't forget your gum,
Regards
Jean
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