The FAA has standard turbulence reporting criteria, but there is a problem. Because of it, turbulence reports can leave you all shook up — you can get a pilot report of only light turbulence and then find you are really getting tossed. To understand what’s going on let’s take a look at the reporting procedure…
The Rules: The FAA asks pilots to report turbulence as Light, Light Chop, Moderate, Moderate Chop, Severe, or Extreme. In order to classify the ride properly, pilots should know the symptoms and degree of each category.
- Light & Light Chop – Occupants feel a slight strain against seat belts. Unsecured objects may be displaced slightly.
- Moderate & Moderate Chop – Occupants feel definite strain against seat belts. Unsecured objects are dislodged.
- Severe – Occupants are forced violently against seat belts. Unsecured objects are tossed about. Aircraft may be momentarily out of control.
- Extreme – The entire aircraft is violently tossed about and is practically impossible to control. Structural damage may result.
Problem: All pilots — regardless of the size of their airplane — use these categories.
If light turbulence is being reported by a Cessna 152 that’s one thing, but light turbulence reported by a Boeing 767 is quite another. It is all a matter of physics. Large, massive objects (like a 767) require a much greater force to cause displacement than smaller, lighter objects (like a 152). The magnitude of the turbulence force needed to produce a ‘light’ report from a 767 would toss a 152 like a leaf. Turbulence that is reported as ‘light’ can be very misleading and might actually turn out to be ‘moderate or severe’ for the light airplane pilot.
Solution: Always ask the FSS briefer what type of aircraft originated a pilot report about turbulence. A written pirep lists the airplane type in a make and model code. If you are not sure what the code means and therefore don’t know how large the aircraft was that made the report – ASK.
Remember: Physics rules can’t be broken – but airplanes can!