Performance and Limitations - QT

Lesson Quicktakes cover the items that should be memorized from each of the wifiCFI Lessons. They do not cover all of the lesson details in-depth.


Indicated Altitude = The Altitude read off the altimeter in flight.

True Altitude = The Altitude above mean sea level (MSL).

Absolute Altitude = The Altitude above ground level (AGL).

Pressure Altitude = The Altitude above the Standard Datum Plane (29.92).

Density Altitude = The Altitude at which the aircraft will perform. Regardless of actual altitude.


Hotter Temperatures = Higher Density Altitude (worse aircraft performance).

Cooler Temperatures = Lower Density Altitude (better aircraft performance).

Increased Humidity = Decreased Aircraft Performance.

Decreased Humidity = Increased Aircraft Performance.

Higher Pressure = Increased Aircraft Performance.

Lower Pressure = Decreased Aircraft Performance.


Indicated Airspeed = The Airspeed read off the Airspeed Indicator.

Used for: Speed limits, ATC speed restriction, aircraft V-speeds.

Calibrated Airspeed = Indicated Airspeed corrected for Pitot Tube Installation.

Used to: Calculate True Airspeed.

True Airspeed = Speed of the Aircraft relative to the airmass in which it is flying.

Used to: Calculate Groundspeed.

Groundspeed = The speed of the Aircraft over the surface of the Earth.

Used for: Time and distance calculations.


Vso = power off stalling speed in the landing configuration.

Vs1 = power off stalling speed in a specified configuration.

Vy = best rate of climb speed - Maximum increase in altitude per unit of time.

Vx = best angle of climb speed - Maximum increase in altitude per horizontal distance unit.

Vle = max speed the aircraft can be operated with the landing gear extended.

Vlo = max speed at which the landing gear can be safely extended or retracted.

Vfe = max permissable speed with the wing flaps extended to a specified degree.

Va = design maneuvering speed.

Vno = maximum structural cruising speed.

Vne = the speed that should never be exceeded in flight.

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