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Flying in IMC with a stormscope and no radar

Following this very good thread I wonder what meteo data people use to be fairly sure a TS is not going to suddenly build up around them.

I recall one story from a TB20 pilot flying in Greece who was suddenly totally surrounded by thunderstorms. She hung in there and didn’t get hit but it was extremely rough. However this was years ago and I don’t know the details of any preflight briefing.

The simplest method I know about is in the form of troughs depicted on the MSLP charts e.g.

Anything could build up in that region because it shows a tendency to convective activity. Another way would be to look at the temperature lapse rates on the forecast skew-T charts but the people who draw the MSLP charts do exactly that anyway and they are paid to do this 24/7…

Administrator
Shoreham EGKA, United Kingdom

Another one is sferics and this is the best site (I would say perhaps the only one which actually works)

Most of us will never have radar but most of us have or can get a stormscope. But radar may not show anything which is just “thinking about it” whereas a stormscope can show the early stages. Also a radar image obtained before or during the flight e.g. Meteox can show a load of muck but the tops may be only say 8000ft so it can be a highly “false no-go” indication for enroute flight

Administrator
Shoreham EGKA, United Kingdom

I think (satellite) internet on board fully obsoleted stormscopes. Those devices are highly unreliable.

Neither with a stormscope nor internet weather I would fly through convective IMC. Doing this requires both an onboard radar and internet weather to see the bigger picture (e.g. what is behind the cell you’re about to circumnavigate).

Doing this requires both an onboard radar and internet weather…

The vast, vast majority of aircraft, especially almost every airliner out there, manages fairly well with onboard weather radar only

EDDS - Stuttgart

I think (satellite) internet on board fully obsoleted stormscopes. Those devices are highly unreliable.

Not sure about “unreliable” (my WX500 picks up every little buildup that I can see) but where do you get a georeferenced sferics display over the internet?

The vast, vast majority of aircraft, especially almost every airliner out there, manages fairly well with onboard weather radar only

Yes but they have

  • FL300+ ceiling so rarely in IMC when enroute
  • +5000fpm climb rate
  • full anti-ice
  • excellent lightning protection (and they do get hit quite a lot)
Administrator
Shoreham EGKA, United Kingdom

what_next wrote:

The vast, vast majority of aircraft, especially almost every airliner out there, manages fairly well with onboard weather radar only

At typical GA altitudes, you have much more IMC time than with airliners. Obviously you can manage without being able to look behind a cell as you can still make sure to remain clear but the utility value of seeing the bigger picture is massive. Additionally, there is a huge difference in what a typical GA radar (especially the predominant 1970s type) can do versus what an airliner or business jet can do with its radar.

excellent lightning protection (and they do get hit quite a lot)

But they really shouldn’t. Many Asian carriers are said to terminate their captain’s contracts after a lightning strike so some of them make 30-50NM detours around cells in order to keep their jobs.

+5000fpm climb rate

Below FL100 maybe. At FL 300 it will rather be 500fpm unless on a positioning flight. Flying over storm cells is rarely an option for anything less powerful than an SR71.

Additionally, there is a huge difference in what a typical GA radar (especially the predominant 1970s type) can do versus what an airliner or business jet can do with its radar.

I have flown many hours behind that stuff and had no problems. When flying a Seneca or C210 (or anything else that cruises with 170KT around FL150) 30-50NM of good look-ahead capability is plainly sufficient. And even the worst legacy green-screen radar will give you that.

EDDS - Stuttgart

what_next wrote:

Flying over storm cells is rarely an option for anything less powerful than an SR71.

I wasn’t referring to overflying active TS but to the fact that you very rarely fly in IMC that has embedded TS (outside terminal areas), you typically fly over the IMC and around the TS cells which gives you a very good orientation.

Last Edited by achimha at 23 Nov 09:57

For what I fly the stormscope and the satellite weather receiver (seem to be) sufficient. The only problem is the coverage. But I would not fly in IMC for longer periods and towards fronts again without the sat weather system …

Obviously this post is asking for a shameless marketing plug on my part:

First notice of a problem ahead using the ADL120 data link:

Then we broke out of the IMC and could also see it. This illustrates what Achim wrote. At FL230 we managed to get above the IMC base so we could see the buildup.

By now also the on board radar was showing the two connected weather cells. But beyond 40NM the returns are rather weak

By then Italian ATC gave us a shortcut to CHI but that only made things worse. So we started a daviation to the left:

Continuing on the deviation:

Passing the weather:

This is the first look we had behind the cell:

The path further south was clear and we could continue direct CHI:

Could this flight be made without the ADL120 datalink weather? Probably yes but with the data link it is much more relaxed and we can save track miles by asking for deviations early on.

Last Edited by Sebastian_G at 23 Nov 10:48
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