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Damon Hemstrom Burton

Wake Turbulence Categories/RECAT-EU

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Last night whilst observing ESSA, I heard an interesting exchange between a pilot and the controller (I believe @Martin Loxbo??) regarding the aircraft's Wake Turbulence Categorisation. Quite interesting, as the pilot, quite rightly, deemed that his aircraft was ICAO Category "M" - Medium, but EuroScope has it recorded as an "L" - Light WT aircraft.

But, here in the EU/EASA nations, a re-categorisation of ICAO wake turbulence separation minima on approach and departure, called “RECAT-EU” has been developed. The RECAT-EU scheme compares turbulence and separation between aircraft types, with categories (according to Eurocontrol) :

Quote

ICAO

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 [as well as S (Super) for A380]

Eurocontrol  RECAT-EU

CAT A - "Super Heavy"
CAT B - "Upper Heavy"
CAT C - "Lower Heavy"
CAT D - "Upper Medium"
CAT E - "Lower Medium"
CAT F - "Light"

So, the aircraft, before WAKE RECAT was deemed Category M, but WAKE RECAT defines it as a Light, Category F aircraft. 

How would such an aircraft be managed in such situation? This is slightly confusing, as in a departure/arrival sense, the ICAO separation of 5nm between Heavy and Medium and between Heavy and Light is usually given. But in this situation, the aircraft's mass deems it as a Medium category, yet WAKE RECAT deems it a Light? Are the WAKE-RECAT separation principles applied, or are standard ICAO? What is the difference between these two in a simulated environment?

 

Edited by Damon Hemstrom Burton

Med vänliga hälsningar | With kind regards

Damon Hemström Burton (1270930) 

5aa038026e870_Louise-Swinglish-Flagsmall.jpg.738ae05b06b664de8db44b0a1bb6cc48.jpg Jag svarar kanske på Engelska då det ser konstigt ut när jag skriver på Svenska även om jag förstår allt ni säger...

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Yes, for some reason H25B (and H25A, H25C) is listed as L in our data files, which is strange because with an MTOW of around 14 tonnes it's a lot more than 7 tonnes which is the limit for Light. Luckily we can correct errors like this easily in the files. :)

RECAT-EU is a different story and to be honest I haven't heard much about it yet. It does seem like it will become a bit more complicated to remember the different categories and separations. I remember when doing the theoretical exams for ATPL as well as for ATC you had to know all the details by heart. I'm not sure if that will work with so many different categories and separations, then again today there are many tools available to the controller.

Any real life TWR/APP controllers out there who know more about this?

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If it’s the case that it’s only our data files, there might be more - I’ve just noticed the Falcon (FA50 and FA7X) both are having a similar issue, as are the Lears (LJ35,LJ45,LJ55) mf.l 

Something to look into?

Quick google search also showed discrepancies in some GNG Aero-Nav sector files so might not just be a SCA issue, or it might be me misunderstanding designations.


Med vänliga hälsningar | With kind regards

Damon Hemström Burton (1270930) 

5aa038026e870_Louise-Swinglish-Flagsmall.jpg.738ae05b06b664de8db44b0a1bb6cc48.jpg Jag svarar kanske på Engelska då det ser konstigt ut när jag skriver på Svenska även om jag förstår allt ni säger...

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I just had a look through the ICAO_Aircraft.txt file and it's got quite a few of these anomalies, mostly for "bizjet sized" aircraft. Like you said Learjets are listed as Light, as are Citations (some ARE Light but the heavier ones are also listed as L), Dornier 328, Douglas DC-3, most Falcons, Short 360 etc.

I've been digging through my folders and found an old version of the file where these wake categories are correct, so apparently at some point these errors have been introduced. @Juha Holopainen, do you have any idea about this? I remember replacing the ICAO_Aircraft.txt with an updated version but I never imagined it would have the wrong WTC for so many aircraft.

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Where was the bad datafile downloaded from? Both the one Martin posted last year on the controller forum and the one I’ve updated (included in the Finnish sector file package) appear to have the correct categories for all the mentioned types. I can’t test the files right now though so there may be a hidden flaw causing EuroScope to interpret them wrong.

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From what I can tell, since AIRAC 1809 the Datafiles folder has been included with the Swedish ES package, and the ICAO_Aircraft.txt in these packages have the wrong WTC for many types.

@Petter Jakobsson, did you maybe get the ICAO_Aircraft file from GNG for these packages?

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On 3/6/2019 at 9:24 PM, Martin Loxbo said:

Any real life TWR/APP controllers out there who know more about this?

Just to clarify, RECAT-EU has not been implemented yet (at least not anywhere in Scandinavia). So everything is business as usual. And knowing how long it usually takes to implement new rules in aviation (just think about 8,33 kHz spacing ...) I guess it will be another 5-10 years before it is used everywhere.

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In the current file that is included in the file package all the aircrafts you have mentioned is correctly defined. This file was last changed 16 June 2019 21:40. There was a time (a year a go maybe) that I used data from GNG but when reports of errors came I did a roll back to the old file. Can you guys experiencing these problem have a look at the time stamp of your file and see if it works to update the file to the current one?

 

As @Jonathan Hougaard said, RECAT-EU is not implemented in the north yet. To my knowledge it is only used in Paris-Charles De Gaulle and at London Heathrow as part of their time based seperation.

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