Definitions of turbulance

RalphInCA

RalphInCA

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RalphInCA
Where can I find "official" definitions of turbulance? I.E. What light chop, moderate chop, severe turbulance means?
 
CTLSi said:
Turbulence: In fluid dynamics, turbulence or turbulent flow is a flow regime characterized by chaotic property changes. This includes low momentum diffusion (bumps), high momentum convection (chop), and rapid variation of pressure and velocity in space and time (shear).
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Umm, that's true, but it has nothing to do with what "light chop" is.

The AIM reference is the correct one. There is an analogous Navy chart, but it isn't any different.

The OP is asking a good question. Many light aircraft pilots drastically overreport turbulence.

I heard a report of "severe" over Half Moon Bay once, from a 172, to NorCal. NorCal asked if they needed clearance (it was under Class B). Severe turbulence means momentary loss of control, and the appropriate action is to get the F out of there so it doesn't turn into extreme.

I experienced moderate on that flight. I think the other pilot did, too, though there is no way to know.
 
According to my CFI

light turbulence = most passengers will think it is medium to heavy
mod turbulence = in small planes you will be hitting your head on the roof of the plane
heavy turbulence = you really do not want to do this in a small plane
sever turbulence = you do not want to do this in any plane
 
drotto said:
According to my CFI

light turbulence = most passengers will think it is medium to heavy
mod turbulence = in small planes you will be hitting your head on the roof of the plane
heavy turbulence = you really do not want to do this in a small plane
sever turbulence = you do not want to do this in any plane
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That's not bad, but there is no "heavy."

The way I like to explain it is:

Light: You spill your coffee. You may shift things around the cabin.
Moderate: Whatever was on the seats is now on the floor. You're having some trouble maintaining airspeed and altitude. You're getting worried about where the tow bar is.
Severe: You "lose it" for brief moments.
Extreme: You can't control the airplane.

Obviously, extreme is a life threatening situation, and you never want to let it go that far. Even moderate is very unpleasant.

But the little thermal vibes we get every day are not significant. They don't even register.
 
Last edited:
MAKG1 said:
Umm, that's true, but it has nothing to do with what "light chop" is.

The AIM reference is the correct one. There is an analogous Navy chart, but it isn't any different.

The OP is asking a good question. Many light aircraft pilots drastically overreport turbulence.

I heard a report of "severe" over Half Moon Bay once, from a 172, to NorCal. NorCal asked if they needed clearance (it was under Class B). Severe turbulence means momentary loss of control, and the appropriate action is to get the F out of there so it doesn't turn into extreme.

I experienced moderate on that flight. I think the other pilot did, too, though there is no way to know.
Click to expand...

The terms light chop, chop, soupy, squirrely, snotty, bumpy, kicked-in-the-teeth, thru the ringer, lousy, rocky, head-banger, makes-a-grown-man-cry are all the same kind of term.

None are technical, none are quantifiable. You cannot say one person chop is another person's chop, nor can you say even the term turbulence (check spelling) is non-subjective.

You can count on the terms wind shear, convective sigmet, mountain wave, cross-wind, thermal, severe updraft/downdraft to mean something specific. Learn those...you will do better.

Is the point....
 
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