2007-12-06 07:00:40 · 6 answers · asked by Anonymous in Cars & Transportation ➔ Aircraft
Barometric pressure falls as altitude increases. Not all airfields are at sea level. Since it is air pressure that keeps an aircraft flying, for any given aircraft there is a maximum altitude of the runway beyond which the air would be too thin to support the weight of the aircraft at takeoff speed. Your aircraft is limited to landings and takeoffs below 8400 ft.
2007-12-06 07:09:00 · answer #1 · answered by Michael B 6 · 3⤊ 0⤋
It is the maximum pressure altitude that the aircraft is allowed to perform a takeoff or landing.
On a standard day, this would be the same as the elevation of the airport, so takeoff at any airports above 8400ft ASL would be prohibited. Low pressure systems will make the pressure altitude higher than the airport altitude.
To find the pressure altitude at the airport your plane is at, turn the aircraft's altimeter to 29.92 inches of mercury and read the altitude displayed.
2007-12-06 07:56:46 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Michael B has it right on. Another term for this is 'density altitude', which takes into account temperature, humidity, barometric pressure, and altitude, to figure out how much lift is available from the ambient air.
Air is denser, and thus provides more lift, if it is dry, cool, and has high barometric pressure (the result of the weather and altitude). This affects maximum takeoff weight, as well as necessary takeoff power. Modern jet aircraft computers take this into account, to determine engine power required for safe takeoff. This avoids using too much power, which puts unessecary wear and strain on the engines.
2007-12-06 07:56:57 · answer #3 · answered by Harry 5 · 0⤊ 0⤋
Sounds like a performance limitation on a specific aircraft.
It basically means that the aircraft isn't permitted to take off or land at pressure altitude (the altitude as seen on the altimeter) above 8400ft
2007-12-06 09:04:11 · answer #4 · answered by helipilot212 3 · 0⤊ 0⤋
That is an aircraft limitation meaning that takeoff or landing is PROHIBITED is the pressure altitude is greater than 8,400'
2007-12-06 14:35:42 · answer #5 · answered by Jason 5 · 0⤊ 0⤋
Punctuate it correctly and tell us the context.
[And pressure altitude and density altitude are not usually the same].
2007-12-06 07:36:15 · answer #6 · answered by Mark 6 · 0⤊ 2⤋