What is RECAT? ​

RECAT (Re-Categorization of wake turbulence) replaces the old four-tier system (Light, Medium, Heavy, Super) with six categories labeled A through F. The traditional system lumped together aircraft with very different wake characteristics - a B757 and a Cessna both counted as "Medium" despite having completely different wake signatures. RECAT fixes that.

The six categories ​

The biggest win is separating what used to be a single "Heavy" bucket into B and C, and what used to be "Medium" into D and E. This lets controllers apply tighter spacing where the actual wake risk is lower.

RECAT separation matrix ​

Minimum distance (nm) the follower must maintain behind the leader:

A dash means standard radar separation applies (3nm in terminal, 5nm en-route). The matrix is asymmetric - a Cat F aircraft behind a Cat A needs 8nm, but a Cat A behind a Cat F just needs standard separation.

How this affects controllers ​

Sequencing arrivals ​

Wake spacing is usually the bottleneck on final approach. When you're running a steady stream of D-category narrowbodies (737s, A320s), you can maintain 3nm spacing in the terminal area. Drop a Cat B widebody into the sequence and suddenly the next two or three aircraft behind it need 4-5nm instead of 3nm. That's a 30-60 second gap that ripples back through the arrival stream.

Departure spacing ​

Departures from the same runway need wake spacing too. A Cat F behind a Cat A can't roll for about 3 minutes. When mixing light GA traffic with heavy jets, this becomes the primary constraint on departure rate.

Altitude considerations ​

Wake vortices sink at about 300-500 fpm and tend to level off roughly 800-1000 ft below the generating aircraft. A common technique is to keep following aircraft above the flight path of the heavier leader, especially on approach.

Mixed traffic environments ​

The real complexity comes at airports with diverse traffic - a busy field handling everything from C172s to A380s. Each pair in the sequence may need different spacing, and the controller has to build those gaps while keeping the flow efficient.

RECAT vs traditional categories ​

The old system required 6nm between any Heavy and a following Medium. Under RECAT, a Cat D behind a Cat C only needs 5nm, and a Cat D behind another Cat D needs just standard separation. That difference adds up to several extra arrivals per hour at busy airports.

FAA RECAT vs RECAT-EU ​

The FAA and EUROCONTROL developed their RECAT systems in parallel. Both use A-F labels, but they are not the same system.

The FAA version (RECAT Phase I, defined in FAA Order JO 7110.659) has different separation minima and places some aircraft in different categories. The B757 is the biggest difference - FAA RECAT puts it in Cat C (Lower Heavy), while RECAT-EU handles it differently. The FAA is also developing pair-specific separation (RECAT Phase II) that defines spacing per aircraft type pair rather than per category.

FAA RECAT is not mandatory at all US facilities. It requires a facility-specific Letter of Agreement and is active at airports including Memphis, Charlotte, Houston, Louisville, Las Vegas, Phoenix, Denver, and Dallas/Fort Worth. Airports without the LOA still use the legacy Heavy/Large/Small system.

ICAO has not adopted either RECAT variant as a global standard. ICAO Doc 4444 still uses the traditional Heavy/Medium/Light categories as the baseline.

In radarcontrol.io ​

All 142 aircraft types in the simulation have RECAT categories assigned. The category appears in each aircraft's performance data. Browse all aircraft by category on the aircraft index page.

Related: What is wake turbulence? | What are aircraft categories? | How does ATC separation work? | Aircraft types

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