Search Pilot Qualification Course Civil Air Patrol Auxiliary of the United States Air Force

BLOCK ONE High Altitude Flying

Lower air pressure Lower air temperature Stronger winds Different weather phenomenon High-altitude flight operations differ significantly from those at lower flight levels, primarily due to:

Pressure Altitude Pressure altitude is absolute altitude above mean sea level corrected for non-standard atmospheric pressure

Calculating P.A. PA = H x (S ), where PA = Pressure Altitude H = Absolute Altitude S = Barometric pressure corrected for altitude Example: 9,000 absolute altitude, altimeter setting PA= 9, x ( ) PA= 9, x (-1.42) Watch your ± sign! PA= 9, ,313 PA= 10,313

Density Altitude Density altitude is pressure altitude corrected for non- standard temperature

Calculating D.A. DA = PA + 66 x (T - TS), where T = Actual temperature TS = Standard temperature Example: 9,000 absolute altitude, 60°F, altimeter setting DA= PA + 66 x (60 °F °F) DA= PA + 66 x 37.8 DA= 10,313 (from previous example) + 2,495 DA= 12,808

Predicting D.A. Methods of determining altimeter setting –ATIS or AWOS for closest airport –Surface observation from FSS or DUATS Methods of determining temperature aloft –Consult Winds and Temperatures Aloft forecast –Obtain local surface temperature, then subtract 3.5°F for each 1,000 feet of altitude above reporting point

Remember: As density altitude increases, the difference between indicated airspeed and true airspeed increases

Remember: As density altitude increases, available horsepower decreases