Altimetry Flashcards
What is pressure?
The force per unit area.
What is a dyne?
A dyne is the force required to produce an acceleration of 1cm/s^2 for a mass of 1g.
What is a hPa?
A Hectopascal is 1000 dynes per square cm.
What are the ISA values for:
- Atmospheric pressure at MSL
- Temperature at MSL
- Lapse rate
- Temperature above 36,000ft
- Atmospheric pressure at MSL: 1013.25hPa
- Temperature at MSL: 1.5 degrees
- Lapse rate: -1.98 degrees/1000ft
- Temperature above 36,000ft: 56.5 degrees
What is the given height for a change in pressure of 1 hPa?
27ft (Normally use 30ft)
Define height
The vertical distance of a level, a point or an object considered as a point, measured from a specified datum.
Define altitude
The vertical distance of a level, a point or an object considered as a point, measured from MSL.
Define elevation
The vertical distance of a point or level on or affixed to the surface of the Earth, measured from MSL.
Define QFE
The atmospheric pressure corrected to a specific elevation.
When is threshold QFE used instead of aerodrome QFE?
When the elevation of the threshold is more than 7ft different to that of the aerodrome.
Define QNH
The atmospheric pressure corrected to MSL.
Define level
A generic term relating to the vertical position of an aircraft in flight and meaning variously height, altitude or flight level.
Define flight level
A surface of constant atmospheric pressure, which is related to a specific pressure datum, 1013.25hPa and is separated from other such surfaces by specific pressure intervals.
Define transition altitude
The altitude at or below which the vertical position of an aircraft is controlled by reference to altitudes.
What is the transition altitude for civil aerodromes in the UK?
3000ft unless otherwise notified.
