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ICAO Wake Turbulence Category

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Category: Wake Vortex Turbulence Wake Vortex Turbulence
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The ICAO wake turbulence category (WTC) is entered in the appropriate single character wake turbulence category indicator in Item 9 of the ICAO model flight plan form and is based on the maximum certificated take-off mass, as follows:

  • H (Heavy) aircraft types of 136 000 kg (300 000 lb) or more;
  • M (Medium) aircraft types less than 136 000 kg (300 000 lb) and more than 7 000 kg (15 500 lb); and
  • L (Light) aircraft types of 7 000 kg (15 500 lb) or less.


Variants of an aircraft type may fall into different wake turbulence categories, (e.g. L/M or M/H). In these cases, it is the responsibility of the pilot or operator to enter the appropriate wake turbulence category indicator in the flight plan.

State Variations to ICAO Wake Turbulence Category

States may elect to operate variations to the ICAO scheme if they wish. One example of this is the UK where the main differences are the re-definition of the lower weight end of the ICAO ‘MEDIUM’ category:

  • An extra category called ‘SMALL’ is defined as aircraft types with an MTOM (maximum take-off mass) of between 17000 kg and 40000 kg
  • The ‘LIGHT’ Category defined in the ICAO scheme is extended to cover aircraft types with an MTOM of up to 17000 kg

In addition an ‘UPPER MEDIUM’ aircraft type category is defined from within the ICAO ‘MEDIUM’ category (only) for approaches made at EGLL EGKK EGSS and EGCC.

Full details of the UK variations are contained in UK AIC P 001/2015 - Wake Turbulence

  • B757. Some states apply a higher category to B757 aircraft than that suggested by the aircraft's weight in case it is the preceding aircraft (i.e. the one generating the wake turbulence).

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