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ATC adverse weather avoidance assistance

Reading this NTSB Report the sentence „The Board’s determination of probable cause is “…the air traffic controller’s failure to provide adverse weather avoidance assistance, as required by Federal Aviation Administration directives, … which led to the airplane’s encounter with a severe thunderstorm and subsequent loss of control.” made me curious on the european status of atc wx avoidance information.

In the US it is convenient: ATC will report precipitation and other hazards frequently and for major stuff reroutings are offered preemptively.

What is the legal basis of this in Europe? Aside from the usual “the PIC is responsible bla bla” is there any legal requirement for ATC to watch out for us bugsmashers and be aware or make aware any predominant wx featured? Is ATC aware of sigmets? Sigcharts?

Thinking of @Peter s Innsbruck LOWI ATC encounter video here, where they deny his wx avoidance request and instead accuse him of scoring a cheap direct routing on the basis of their radar image, which obviously isn’t suitable to identify hazardous icing conditions in a piston single.

I had some challenging VFR flights last week (multiple low pressure areas and occlusions over the Mediterranean).

For the final leg from LJPZ to LOWG I inquired with LJPZ in their briefing room for a second opinion of the wx situation, the guy looked at me like a deer in the headlight, nodded and came back shortly later with a printout of metars and tafs (which I had shown him digitally on my phone before already).
Ljubljana LJLJ Info wasn’t proactive either and mostly concerned about entering Zagreb FIR (who tf cares!), behavior like this could easily stress a pilot if not confident and push one to avoid a virtual airspace boundary instead of avoiding hazardous wx conditions.
A day before LIBR ATC didn’t say a peep and shortly later a 180 was required due to WX.
Apulia Info was helpful the next day advising of bad wx on the route for timely avoiding.

Is it personal preference of the atc guy or gal on duty or are there procedures?

Last Edited by Snoopy at 20 Apr 10:39
Make Aviation Great Again

My experience is that it varies country to country.

For example, Germany is always willing to help, and often offers it proactively, whereas the UK controllers do not even have access to weather information.

EGKB Biggin Hill

Any others agree that this is a major safety issue?
EU: no adsb wx, inconsistent atc advisories, airspace prioritized over safe routings.

Make Aviation Great Again

Sebastian Golze is my friend.

With sufficient training, experience and gumption, it works well even for tactical avoidance, but you can’t just use one reading, you need a series of downloads, a ruler and a grasp of basic maths.

EGKB Biggin Hill

A new thread where you refer about tactical wx avoidance using datalink would be appreciated!
@sebastian_golze could chime in and inform why there is no coverage (iridium limit?) beginning south/east of the med (greece, italy etc…)

Make Aviation Great Again

Snoopy wrote:

refer about tactical wx avoidance using datalink would be appreciated

I have used Golze to make some very precise tactical decisions.

However, it must be emphasised that the best use of the information is to stay right away from areas of intense rainfall, by 30-50nm, especially if you only have one image, and cannot therefore determine the direction of travel and the speed of build-ups.

But, if you expect convective activity, it is a good idea to have the ADL set to Automatic Downloads, even before you take-off (on the ground, you can use Internet downloads to save a little money). Even in the air, it is going to cost a few cents, but in the totality of the costs of flying, it’s not huge.

Once you have Automatic Downloads, by the time you reach the area of activity you might have four to six images, at 15 minute intervals. It is important to note the actual time of each of them, as there is a typical 4 minute processing delay, and there is 15 minutes in between, so the latest image will be between 4 and 19 minutes old.

If successive images don’t form a coherent pattern, it means that thunderstorms are building and collapsing because of local triggers and, again, you must avoid by a large margin.

However, it is much more common that cells develop, and then can be seen travelling for extended periods, often a number of hours.

Under those circumstances you can visualise (using the Play function) the direction of travel, and measure, by going through one by one, the exact position at the exact time the data was recorded. You can then project that information to have a pretty good idea where the cells are probably going to be at the time you reach the area.

I have used this information to ask for different routings, STARs and even runway changes, based on my predictions of where the cells will be.

But please note, this all requires care, precision and intelligence. Only do it if you really understand the system and have a reasonable feel for how unstable weather behaves.

Also, by being in the air on a convective day you are likely to encounter thunderstorms. I suggest that, in addition to Golze, it is much better to have radar and/or Stormscope if you can afford it (both money and weight) and:

  1. Get as high as possible, to increase the chances of being on top of other cloud, so you can see and avoid the big ones (this is more difficult on the arrival and approach, obviously)
  2. If you do get in one, do not overcontrol. If you are in a cell, then the chances of anyone else being in there are very small indeed, so don’t obsess about maintaining altitude or track, just keep gently adjusting back to target, but don’t fight it.
EGKB Biggin Hill

@timothy great post thank you

Make Aviation Great Again

Timothy’s post is excellent (as usual), not least because he underlined the risks. There have been at least a couple of accidents in the US where people without onboard radar have turned straight into thunderstorms, based on lagging sat weather, so this is not something to be taken lightly.

If you ever get into convection (or any type of heavy turbulence for that matter), indeed do not over control – just try to stay right side up and do not let your speed creep up. Actually it may be a good idea to slow down as much as possible, even drop the gear (but never the flaps): Gs and wing loading are your enemy and they increase with the square of your speed. Get to manoeuvring speed.


One example of US ATC going a few extra miles in terms of weather avoidance.
Great flexibility from the PIC too. Living the dream


I think that, per ICAO, ATC responsibility is limited to providing a FIS. They are not required to advise on weather, etc. In the US they can and do more, and in Europe they generally don’t. At the root of it is probably funding, which is a political hot potato…

So nothing can be done.

On top of this, you have variable ELP, on both sides, which supports the present situation by enabling the reliance on standard phraseology. I am sure everybody who flies in Europe (and outside their own patch) can quote frequent examples of where communication only just hangs in there by a thin thread. Expecting ATC to deliver a weather service just isn’t going to work. If you listen to US ATC doing this, they are departing very much from ICAO phraseology in the process, but it works because everyone speaks English (well, sort of ).

Shoreham EGKA, United Kingdom
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