Apollo 50, 55, 60, 65 Minimum Safe Altitude (MSA), Minimum En Route Safe Altitude (MESA)

Navigation Basics

ete aSLE	00:37
0.006 “
Ft01:23	137kts

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.

			TO
			Waypoint
	24	45	63
MEFs				5 nm
	28		63	Buffer
		65
	52	148	141
				MESA
FROM

Waypoint

eta aSLE 01:23 MinSafeA 7200’ 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

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