PIREPs - So you want to sound like a pro.

Arnold

Cleared for Takeoff
Joined
Mar 8, 2005
Messages
1,480
Location
Philadelphia Area
Display Name

Display name:
Arnold
We had "mild" Ice
We had "heavy turbulence


Knowledgeable professional pilots would never give these report. Why? Because they know there is no definition of "mild icing" or "heavy turbulence." Yet this language pops up in pilot reports from time to time.

When giving a PIREP to this board or the FAA it helps to use agreed upon terms. The AIM contains definitions for four icing intensity levels.

From AIM 7-1-19:

  • Trace. Ice becomes noticeable. The rate of accumulation is slightly greater than the rate of sublimation. A representative accretion rate for reference purposes is less than ¼ inch (6 mm) per hour on the outer wing. The pilot should consider exiting the icing conditions before they become worse.
  • Light. The rate of ice accumulation requires occasional cycling of manual deicing systems to minimize ice accretions on the airframe. A representative accretion rate for reference purposes is ¼ inch to 1 inch (0.6 to 2.5 cm) per hour on the unprotected part of the outer wing. The pilot should consider exiting the icing condition.
  • Moderate. The rate of ice accumulation requires frequent cycling of manual deicing systems to minimize ice accretions on the airframe. A representative accretion rate for reference purposes is 1 to 3 inches (2.5 to 7.5 cm) per hour on the unprotected part of the outer wing. The pilot should consider exiting the icing condition as soon as possible.
  • Severe. The rate of ice accumulation is such that ice protection systems fail to remove the accumulation of ice and ice accumulates in locations not normally prone to icing, such as areas aft of protected surfaces and any other areas identified by the manufacturer. A representative accretion rate for reference purposes is more than 3 inches (7.5 cm) per hour on the unprotected part of the outer wing. By regulation, immediate exit is required.

The AIM contains definitions for four turbulence intensity levels.

From AIM 7-1-21: (see table 7-19)

Light, Moderate, Severe and Extreme are defined.
 
Back
Top