Turbulence & Altitudes

Mechanical Turbulence

When wind flow is disrupted by mountains, buildings or other obstacles.

Low Level Turbulence

Turbulence below 15,000 MSL

Convection Turbulence

Turbulence that will push you up because of the warm air

Frontal Turbulence

Associated with passing over a front

Wake Turbulence

created by wingtip vortices from behind another aircraft

Clear Air

Invisible, unexpected turbulent movement

Indicated Altitude

The altitude shown directly on the altimeter, provided that it is set to the current altimeter setting.

Absolute Altitude

Vertical distance of an aircraft above the terrain/ground level (AGL).

Density Altitude

Pressure Altitude adjusted for deviations from standard temperature.

Under standard temperatures, pressure altitude and density altitude are equal.

Density Altitude tells you how thick or thin the air feels to the airplane.

• Thinner/Hotter days = plane has to work harder

• Thicker/Colder days = plane finds it easier to fly

True Altitude

The vertical distance above sea level

Commonly measured in feet above Mean Sea Level (MSL).

Pressure Altitude

Altitude displayed when altimeter is set to 29.92hg.

The heigh above the standard datum plane where air pressure is = to 29.92in of mercury at a temperature of 15° C

Which Altitude is depicted on Aeronautical Charts?

True Altitude:

Airport Elevations

Terrain Heights

Obstacle Elevations