ASA Electronics E6-B manual Feet Per Mile vs. Feet Per Minute

If the station altitude is unknown, read calibrated altitude MSL on the middle scale and true altitude MSL on the outer scale.

In Figure 15 the pressure altitude is 10,000 feet, station altitude is 5,000 feet, outside air temperature is -19°C,andyourindicated(calibrated)altitudeis12,000 feet. The difference between 5,000 feet station altitude and 12,000 feet indicated altitude is 7,000 feet. Oppo- site 7,000 feet on the middle scale read correction to station altitude (6,600 feet) on the outer scale—5,000 feet plus 6,600 feet equals 11,600 feet true altitude.

CAUTION: If the temperature between the sur- face and the aircraft does not decrease at the standard rate of 2°C per 1,000 feet or if the pressure at flight level is nonstandard, reliance on a com- puter solution to determine obstruction clearance can be very hazardous.

Find True Altitude: (Answers are on Page 38)

		INDICATED/
	PRESSURE	CALIBRATED		STATION	TRUE
	ALTITUDE	ALTITUDE	TEMP	ALTITUDE	ALTITUDE
1.	10,500	10,000	-20°C	5,000
2.	12,000	11,000	-30°C	3,000
3.	8,000	7,600	-15°C	(unknown)

Feet Per Mile vs. Feet Per Minute

Because aircraft performance characteristics vary dramatically between types, the FAA establishes climb and descent requirements in feet per mile, rather than in feet per minute. A climb of 300 feet per mile will result in a 3° climb angle for any aircraft; a light trainer climbing at that angle at 90 knots

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