Minimum Safe Altitude (Msa); Minimum En Route Safe Altitude (Mesa) - Garmin Apollo GX 50 User Manual

Navigation Basics
MEFs
5
FROM
Waypoint
3-8
ete aSLE
0.006
Ft01:23

Minimum Safe Altitude (MSA)

MSA is calculated by taking the Maximum Elevation
Figure (MEF) from the sectional chart grid that
corresponds to your current position. In areas below
3,000 feet, 1,000 feet is added. In areas above 3,000
feet, 2,000 feet is added. In the example below, the
current aircraft would be considered to be at 7,000
feet. If you are within 5 nm of another grid with a
higher MEF, the higher MEF will be used. The MEF
on the sectional chart is derived by taking the altitude
of the highest obstruction within the grid, rounded up
to the next 100 feet, and adding 300 feet. For example,
if the highest obstruction is 4,728 feet, the MEF
would show as 5,100 feet.
2
4
2 8
2
14
eta aSLE
MinSafeA
EnrtSafeA 16800'

Minimum En Route Safe Altitude (MESA)

Minimum En Route Safe Altitude is the highest MSA
for every point between the aircraft present position
and the "TO" waypoint with a 5 nm buffer around
the course. The value will be replaced with dashes if
there is no valid GPS position, the TO waypoint is
blank, or the current position is outside of the
00:37
"
137kts
4
5
6
6 5
8 14
01:23
7200'
TO
Waypoint
6 3
5 nm
3 Buffer
1
MESA