Wake Turbulence Separation

Wake turbulence refers to vortex turbulence generated by aircraft, particularly during takeoff and landing. Controllers must ensure minimum separation distances to prevent accidents caused by wake turbulence.

When is Wake Turbulence Separation Required?

Wake turbulence separation applies in situations where wake turbulence is expected, including:

Enroute Separation (Radar-Separated Aircraft)

Separation is required if:

• An aircraft is directly behind another aircraft at the same altitude or less than 1000ft below.
• An aircraft crosses behind another aircraft at its 6 o’clock position, at the same altitude or less than 1000ft below.

Approach and Departure Phases

Separation is required when:

• An aircraft is directly behind another aircraft at the same altitude or less than 1000ft below.
• An aircraft crosses behind another aircraft at its 6 o’clock position, at the same altitude or less than 1000ft below.
• Both aircraft use the same runway or parallel runways less than 760m apart.
• Aircraft use crossing or parallel runways (760m or more apart) and one aircraft flies through the flight path of the preceding aircraft at the same altitude or less than 1000ft below.

Exceptions: When Wake Turbulence Separation is NOT Required

Wake turbulence separation does not apply to:

• VFR approach flights.

• IFR approach flights performing a visual approach, where the pilot:

  • Has reported the preceding aircraft in sight.
  • Has been instructed to follow it and maintain their own separation.

In these cases, a wake turbulence warning must be issued: "CAUTION WAKE TURBULENCE".

Phases of Flight for Wake Turbulence Application

Departure Phase

A VFR flight remains in the departure phase until:

• Reaching 1000ft above aerodrome level.
• Reaching level flight.
• Entering right downwind.

Approach Phase

A VFR flight is in the approach phase when:

• It is at or below 1000ft above aerodrome level.
• It has entered the traffic pattern.
• It has begun final descent within a control zone.

Special Cases:

• A touch-and-go is considered an approaching aircraft until touchdown, after which it is handled as a departing aircraft.
• A low approach is considered approaching until it crosses the runway threshold, after which it is considered departing.

Wake Turbulence Categories (WTC)

Aircraft are categorized based on Maximum Takeoff Mass (MTOM):

Note:

• Aircraft in the Super (J) category are treated as Heavy (H) above FL100.
• WTC information is always available in the flight plan.

Minimum Wake Turbulence Separation Values

Wake turbulence separation can be distance-based or time-based.

• Distance-based separation is the default standard.
• Time-based separation applies when distance-based separation is not feasible.

Distance-Based Wake Turbulence Separation

Time-Based Wake Turbulence Separation

Time-based separation is used for departing and approaching aircraft.

If an aircraft departs from an intersection or crossing runway, 1 minute is added to the separation value.

Minimum Time Separation: Successive Landings or Full Length Take Offs

Minimum Time Separation: Intermediate Take Off After a Full Length Take Off

Minimum Time Separation: Mixed Arrival/Departure Use with Displaced Threshold

Minimum Time Separation: Opposite Direction Use by Successive Aircraft