Parameter 8: Pressure Altitude & Relative Altitude
The eA990R measures pressure altitude and not absolute altitude
(unlike a GPS). Pressure altitude is a relative altitude measurement
based on barometric pressure. Pressure altitude is the altitude
indicated by an altimeter that is adjusted to measure height above
the Standard Datum Plane. The Standard Datum Plane is a
theoretical level where the weight of the atmosphere is 29.92 inches
of mercury.
As atmospheric pressure changes, the Standard Datum
Plane may be below, at, or above sea level.
Pressure altitude is most commonly used for aviation planning.
To measure pressure altitude,
press the Mode button 7 times
after
turning on the anemometer. Press the
Units button
to switch from
feet to meters.
1. Altitude Units: ft, m
2. Max/Min/Avg Indicator
3. Hold Current Altitude Reading
4. Beaufort Scale
5. Altitude Value
