Garmin GPS 90 - Manual (Page 63)

The Main Menu page also provides access to the GPS
9 0 ’s E6-B functions, which can be used to calculate
density altitude, winds aloft, fuel usage, sunrise & sunset
and vertical navigation profiles.
To calculate density altitude and true air speed:
1. Highlight the indicated altitude field (IAlt) and press E .
2. Enter the altitude from your altimeter and press
E
.
3. Press
E
to begin entry of your calibrated airspeed
(CAS).
4. Enter the calibrated airspeed and press E .
5. Press E to begin entry of your current altimeter setting.
6. Enter the altimeter pressure and press E .
7. Press
E
to begin entry of the total air temperature (TAT).
8. Enter the TAT (standard outside air temperature gauge on
most piston aircraft) and press the E key.
The calculated density altitude and true airspeed will
be displayed at the bottom of the page.
The GPS 90 winds aloft function will calculate the
wind direction, speed and head/tail wind conditions for
you from by entering your true air speed and curre n t
heading.
To calculate winds aloft:
1. Highlight the true airspeed field (TAS) and press
E
.
2. Enter the TAS (use the density altitude function if you do not
know TAS) and press E .
3. Press E to begin entry of your current heading (Hdg).
4. Enter your heading and press E .
The wind direction, speed and the head/tail wind
conditions will be displayed at the bottom of the winds
aloft page.
55
E6-B Menu
Density Altitude
& Winds Aloft
Calculating density
altitude and true
air speed.
Calculating winds
aloft.
gps 90 manual 8/6/98 10:00 AM Page 55