AIM

8/15/19

7

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3

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8

Wake Turbulence

2.

In the opposite direction on the same runway

behind a B757 takeoff or low/missed approach.

NOTE

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This 3

−

minute interval may not be waived.

e.

A 4

−

minute interval will be provided for all

aircraft taking off behind a super aircraft, and a
3

−

minute interval will be provided for all aircraft

taking off behind a heavy aircraft when the operations
are as described in subparagraphs c1 and c2 above,
and are conducted on either the same runway or
parallel runways separated by less than 2,500 feet.
Controllers may not reduce or waive this interval.

f.

Pilots may request additional separation (i.e.,

2 minutes instead of 4 or 5 miles) for wake turbulence
avoidance. This request should be made as soon as
practical on ground control and at least before taxiing
onto the runway.

NOTE

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14 CFR Section 91.3(a) states: “The pilot

−

in

−

command of

an aircraft is directly responsible for and is the final
authority as to the operation of that aircraft.”

g.

Controllers may anticipate separation and need

not withhold a takeoff clearance for an aircraft
departing behind a 

large, heavy, 

or

 super

 aircraft if

there is reasonable assurance the required separation
will exist when the departing aircraft starts takeoff
roll.

NOTE

−

With the advent of new wake turbulence separation
methodologies known as Wake Turbulence Recategoriza-

tion, some of the requirements listed above may vary at
facilities authorized to operate in accordance with Wake
Turbulence Recategorization directives.

REFERENCE

−

FAA Order JO 7110.659 Wake Turbulence Recategorization
FAA Order JO 7110.123 Wake Turbulence Recategorization 

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  Phase II

FAA Order JO 7110.126, Consolidated Wake Turbulence

7

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3

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10. Development and New Capabilities

a.

The suite of available wake turbulence tools,

rules, and procedures is expanding, with the
development of new methodologies. Based on
extensive analysis of wake vortex behavior, new
procedures and separation standards are being
developed and implemented in the US and
throughout the world.  Wake research involves the
wake generating aircraft as well as the wake
toleration of the trailing aircraft.

b.

The FAA and ICAO are leading initiatives, in

terminal environments, to implement next

−

genera-

tion wake turbulence procedures and separation
standards. The FAA has undertaken an effort to
recategorize the existing fleet of aircraft and modify
associated wake turbulence separation minima. This
initiative is termed Wake Turbulence Recategoriza-
tion (RECAT), and changes the current weight

−

based

classes (Super, Heavy, B757, Large, Small+, and
Small) to a wake

−

based categorical system that

utilizes the aircraft matrices of weight, wingspan, and
approach speed. RECAT is currently in use at a
limited number of airports in the National Airspace
System.