4. Doha Recategorisation Wake Turbulence Separation Minima (RECAT)
4.1 General
Airports within the Doha TMA utilise a revised system of wake turbulence categories to that defined by ICAO to allow for more efficient separation for arriving and departing traffic, increasing airport capacity.
Recategorisation Wake Turbulence Separation Minima (RECAT), the re-categorisation of aircraft is based primarily on maximum take-off mass, wingspan, and approach speed. eWTS splits aircraft into seven categories (A to F), as opposed to the four categories defined in ICAO Doc 4444 (See Section 7).
The use of RECAT allows more efficient use of airspace, reducing separation depending on the leading and following aircraft, maintaining separation in some instances, and increasing separation for the smallest trailing aircraft.
eWTS encompasses both distance-based separation for arriving aircraft as well as time-based separation for departing aircraft and is applied at Doha (OTBD) and Doha-Hamad (OTHH).
4.2 Departures (time-based separation)
4.2.1 Successive full-length departures
| Follower | A | B | C | D | E | F |
|---|---|---|---|---|---|---|
| Leader | ||||||
| A | * | 100s 1m40s |
120s 2m |
140s 2m20s |
160s 2m40s |
180s 3m |
| B | * | * | * | 100s 1m40s |
120s 2m |
140s 2m20s |
| C | * | * | * | 80s 1m20s |
100s 1m40s |
120s 2m |
| D | * | * | * | * | * | 120s 2m |
| E | * | * | * | * | * | 100s 1m40s |
| F | * | * | * | * | * | 80s 1m20s |
| * No wake turbulence separation requirement | ||||||
4.2.2 Departure from an intermediate point following departure from full-length
| Follower | A | B | C | D | E | F |
|---|---|---|---|---|---|---|
| Leader | ||||||
| A | * | 160s 2m40s |
180s 3m |
200s 3m20s |
220s 3m40s |
240s 4m |
| B | * | * | * | 160s 2m40s |
180s 3m |
200s 3m20s |
| C | * | * | * | 140s 2m20s |
160s 2m40s |
180s 3m |
| D | * | * | * | * | * | 180s 3m |
| E | * | * | * | * | * | 160s 2m40s |
| F | * | * | * | * | * | 140s 2m20s |
| * No wake turbulence separation requirement | ||||||
4.3 Arrivals (distance-based separation)
4.3.1 Aircraft on the same localizer course
| Follower | A | B | C | D | E | F |
|---|---|---|---|---|---|---|
| Leader | ||||||
| A | 3 NM | 4 NM | 5 NM | 5 NM | 6 NM | 8 NM |
| B | * | 3 NM | 4 NM | 4 NM | 5 NM | 7 NM |
| C | * | * | 3 NM | 3 NM | 4 NM | 6 NM |
| D | * | * | * | * | * | 5 NM |
| E | * | * | * | * | * | 4 NM |
| F | * | * | * | * | * | 3 NM |
| * No wake turbulence separation requirement | ||||||