Aviation Knowledge Flashcards
Pressure Altitude
Altitude displayed when altimeter is set to 29.92 in of Hg
Density Altitude
Is Pressure altitude corrected for Temperature and Humidity.
What airplane “feels” like it is experiencing.
Example: Taking off from a sea level airport on the coast of Florida, and yet if it is hot and humid, the density altitude could be as high as 5,000 feet, in which case the airplane, even at sea level, requires a longer takeoff run and has a reduced rate of climb.
Indicated Altitude
Altitude displayed on altimeter
True Altitude
Altitude above mean sea level (MSL)
Absolute Altitude
Height above ground level (AGL)
Warm air Affect on Altitude
Warmer air is less dense.
When the temperature rises above the standard temperature for a particular place, the density of the air in that location is reduced, and the density altitude increases
Cold air Affect on Altitude
Cold air is more dense.
When the temperature drops below the standard temperature for a particular place, the density of the air in that location is increased, and the density altitude decreases.
ICE T
Indicated Calibrated Equivalent True
Indicated Airspeed (IAS)
Indicated Airspeed is the speed shown on the airspeed indicator (IAS)
The indicated airspeed is of greater importance than the true airspeed. This is why control speeds (e.g. V1, V2, etc) are given as KIAS (Knots Indicated Airspeed).
Calibrated Airspeed (CAS)
Calibrated Airspeed is indicated airspeed corrected for position installation error
Used for navigation, CAS is traditionally calculated as one of the steps between indicated airspeed (IAS) and true airspeed (TAS);
Used for aircraft control, CAS is one of the primary reference points, as it describes the dynamic pressure acting on aircraft surfaces regardless of the existing conditions of temperature, pressure altitude or wind.
The first application has rapidly decreased in importance due to the widespread use of GPS and inertial navigation systems. With these systems, pilots are able to read TAS and groundspeed directly from cockpit displays. This negates the requirement to calculate TAS from IAS with calibrated airspeed as an intermediate step.
True Airspeed (TAS)
True Airspeed is Calibrated Airspeed (CAS) corrected for altitude and non-standard temperature - the speed of the aircraft relative to the airmass in which it is flying.
TAS cannot be measured directly. In flight, it can be calculated either by using a flight calculator.
Mach Number
The ratio between the true air speed (TAS) and the local speed of sound (LSS).
This ratio, which equals one when the TAS is equal to the LSS, is known as the Mach Number (M) and is very important in aircraft operating at high speed.
