Aeronautical Information Manual (AIM), page 487

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12/10/15                                                                                                                           AIM

7-1-22. PIREPs Relating to Turbulence                                         5. Aircraft altitude or flight level.
  a. When encountering turbulence, pilots are                                 6. Type of aircraft.
urgently requested to report such conditions to ATC                           7. Duration of turbulence.
as soon as practicable. PIREPs relating to turbulence
should state:                                                           EXAMPLE-
                                                                        1. Over Omaha, 1232Z, moderate turbulence in clouds at
    1. Aircraft location.                                               Flight Level three one zero, Boeing 707.
    2. Time of occurrence in UTC.                                       2. From five zero miles south of Albuquerque to three zero
                                                                        miles north of Phoenix, 1250Z, occasional moderate chop
    3. Turbulence intensity.                                            at Flight Level three three zero, DC8.
    4. Whether the turbulence occurred in or near                         b. Duration and classification of intensity should
clouds.                                                                 be made using TBL 7-1-10.

                                                               TBL 7-1-10
                                             Turbulence Reporting Criteria Table
    Intensity             Aircraft Reaction                        Reaction Inside Aircraft              Reporting Term-Definition
    Light       Turbulence that momentarily causes           Occupants may feel a slight strain Occasional-Less than 1/3 of the time.
                slight, erratic changes in altitude and/or   against seat belts or shoulder straps.
                attitude (pitch, roll, yaw). Report as       Unsecured objects may be displaced Intermittent-1/3 to 2/3.
                Light Turbulence; 1                          slightly. Food service may be con-
                or                                           ducted and little or no difficulty is Continuous-More than 2/3.
                Turbulence that causes slight, rapid and     encountered in walking.
                somewhat rhythmic bumpiness without
                appreciable changes in altitude or
                attitude. Report as Light Chop.
    Moderate    Turbulence that is similar to Light          Occupants feel definite strains against                NOTE
                Turbulence but of greater intensity.         seat belts or shoulder straps. Unse- 1. Pilots should report location(s),
                Changes in altitude and/or attitude occur    cured objects are dislodged. Food time (UTC), intensity, whether in or
                but the aircraft remains in positive         service and walking are difficult.      near clouds, altitude, type of aircraft
                control at all times. It usually causes                                              and, when applicable, duration of
                variations in indicated airspeed. Report                                             turbulence.
                as Moderate Turbulence; 1
                or                                                                                   2. Duration may be based on time
                Turbulence that is similar to Light Chop                                             between two locations or over a single
                but of greater intensity. It causes rapid                                            location. All locations should be
                bumps or jolts without appreciable                                                   readily identifiable.
                changes in aircraft altitude or attitude.
                Report as Moderate Chop.1
    Severe      Turbulence that causes large, abrupt         Occupants are forced violently against
                changes in altitude and/or attitude. It      seat belts or shoulder straps. Unse-              EXAMPLES:
                usually causes large variations in           cured objects are tossed about. Food a. Over Omaha. 1232Z, Moderate
                indicated airspeed. Aircraft may be          Service and walking are impossible. Turbulence, in cloud, Flight
                momentarily out of control. Report as                                               Level 310, B707.
                Severe Turbulence. 1
    Extreme     Turbulence in which the aircraft is                                                  b. From 50 miles south of Albuquer-
                violently tossed about and is practically                                            que to 30 miles north of Phoenix,
                impossible to control. It may cause                                                  1210Z to 1250Z, occasional Moderate
                structural damage. Report as Extreme                                                 Chop, Flight Level 330, DC8.
                Turbulence. 1
    1 High level turbulence (normally above 15,000 feet ASL) not associated with cumuliform cloudiness, including thunderstorms,
    should be reported as CAT (clear air turbulence) preceded by the appropriate intensity, or light or moderate chop.

Meteorology                                                                                                                     7-1-43

Page 487 of the Aeronautical Information Manual (AIM.pdf)
AIM: Official Guide to Basic Flight Information and ATC Procedures

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