AA.I.D.K3

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• Pilot's Handbook of Aeronautical Knowledgep. 8-6
  Chapter 8: Flight Instruments › Types of Altitude

  Indicated altitude—read directly from the altimeter (uncorrected) when it is set to the current altimeter setting. 2. True altitude—the vertical distance of the aircraft above sea level—the actual altitude. It is often expressed as feet above mean ... level (MSL). Airport, terrain, and obstacle elevations on aeronautical charts are true altitudes. 3. Absolute altitude—the vertical distance of an aircraft above the terrain, or above ground level (AGL). 4. Pressure altitude—the altitude indicated when the altimeter setting…

• Pilot's Handbook of Aeronautical Knowledgep. 8-6
  Chapter 8: Flight Instruments › Altimeter Operation

  altimeter indicates an altitude above the actual field elevation. If the barometric pressure setting is reset to the current altimeter setting of 29.68 "Hg, then the field elevation is again indicated on the altimeter. This pressure change ... easily noticed in flight since aircraft fly at specific altitudes. The aircraft steadily decreases true altitude while the altimeter is held constant through pilot action as discussed in the previous section. Knowing the aircraft’s altitude is vitally important…

• Airplane Flying Handbookp. 4-2
  Chapter 4: Energy Management: Mastering Altitude and Airspeed Control › Viewing the Airplane as an Energy System › A Frame of Reference for Managing Energy State

  example, if the pilot decides to put all the surplus energy into altitude, the airplane can climb at a constant airspeed. [Figure 4-1A] If the pilot opts to place all the surplus energy into airspeed, the airplane ... accelerate while maintaining altitude. [Figure 4-1B] When drag exceeds thrust, (T – D < 0), the airplane's total mechanical energy decreases. The pilot has two sources of stored energy to tap into. For example, the pilot may choose…

• Pilot's Handbook of Aeronautical Knowledgep. 11-4
  Chapter 11: Aircraft Performance › Density Altitude

  Under conditions higher or lower than standard, these levels cannot be determined directly from the altimeter. Density altitude is determined by first finding pressure altitude and then correcting this altitude for nonstandard temperature variations. Since density varies directly with pressure ... inversely with temperature, a given pressure altitude may exist for a wide range of temperature by allowing the density to vary. However, a known density occurs for any one temperature and pressure altitude. The density of the air, of course…

• Pilot's Handbook of Aeronautical Knowledgep. 4-4
  Chapter 4: Principles of Flight › Pressure › Density Altitude

  Density Altitude SDP is a theoretical pressure altitude, but aircraft operate in a nonstandard atmosphere and the term density altitude is used for correlating aerodynamic performance in the nonstandard atmosphere. Density altitude is the vertical distance above sea level ... propeller is less efficient in thin air • Lift because the thin air exerts less force on the airfoils Density altitude is pressure altitude corrected for nonstandard temperature. As the density of the air increases (lower density altitude), aircraft performance increases…

• Aviation Weather Handbookp. 8-11
  8 Atmospheric Pressure and Altimetry › 8.4.1 Altitude › 8.4.1.2 Indicated Altitude

  True Altitude Since existing conditions in a real atmosphere are seldom standard, altitude indications on the altimeter are seldom actual or true altitudes. True altitude is the actual vertical distance above MSL. If an altimeter does not indicate true altitude ... what does it indicate? 8.4.1.2 Indicated Altitude Figure 8-10 shows the effect of mean temperature on the thickness of three columns of air. Pressures are equal at the bottoms and tops of the three layers. Since an altimeter…