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Incorrect MSAW behavior


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Hello,

I would like to report wrong behavior of MSAW function.

From my observation what does this function do is:

* define an area with specified minimum altitude

* check if the aircraft is within this area and bellow the minimum altitude

* if yes, triggers MSAW warning - thats all

 

In real-world, the MSAW should function like:

* the conditions above apply, except for:

* VFR flights - no VFR flights get MSAW warnings - ever

* Non-FPL flights - no MSAW ever

* Flights following their route - no MSAW - because the route usually has lower minimum altitudes (should we call it MOCA, minimum flight altitude or whatever you prefer) than the whole sector - in Euroscope we could easily exclude aircraft which are not having RAM warning - other words, MSAW should only apply on aircraft having RAM warning -> being of the route.

* Flights in their approach phase - in real world there are MSAW exclusion areas along runway centerlines (+- some degrees). In euroscope we could nicely exclude all aircraft with approach being selected in their CFL (same as we already exclude those on-approach airplanes from RAM and CLAM warnings)

 

With present state of MSAW function, it is completely unusable in Euroscope. Sorry.

 

Pavel

Pavel Brodsky

VACC-CZ

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I agree with you expect this statement:

* Flights following their route - no MSAW - because the route usually has lower minimum altitudes (should we call it MOCA, minimum flight altitude or whatever you prefer) than the whole sector - in Euroscope we could easily exclude aircraft which are not having RAM warning - other words, MSAW should only apply on aircraft having RAM warning -> being of the route.

 

According my knowledge, MSAW warnings are intended to indicate an aircraft is descending below the coverage of radar. In areas where you provide radar services, also no airway minimum should be lower. Otherwise you won't provide radar service in this area anyway and therefore not define a MSAW area.

 

I would also restrict the warning to IFR aircraft not cleared for an approach and [Mod - Happy Thoughts]igned to the current controller.

Jonas Kuster Leader Operation - vACC Switzerland | www.vacc.ch

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  • 2 weeks later...

Hi Pavel,

 

I have tried to implement this function into my controller pack a few months ago, I did have the same problem as you with MSAW, about VFR and traffic with no-FPL.

 

I have asked Gergely, he told me it wasn't fully implemented yet, that's why you don't have anything about MSAW in the Docomeentation.

 

Wait & See!

Edited by Guest
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I agree with you expect this statement:
* Flights following their route - no MSAW - because the route usually has lower minimum altitudes (should we call it MOCA, minimum flight altitude or whatever you prefer) than the whole sector - in Euroscope we could easily exclude aircraft which are not having RAM warning - other words, MSAW should only apply on aircraft having RAM warning -> being of the route.

 

According my knowledge, MSAW warnings are intended to indicate an aircraft is descending below the coverage of radar. In areas where you provide radar services, also no airway minimum should be lower. Otherwise you won't provide radar service in this area anyway and therefore not define a MSAW area.

 

I would also restrict the warning to IFR aircraft not cleared for an approach and [Mod - Happy Thoughts]igned to the current controller.

 

Not agree... Check following charts, example from Czech AIP, LKMT airport.

STAR chart: http://lis.rlp.cz/ais_data/aip/data/valid/a2-mt-star22n.pdf

Minimum vectoring altitude chart: http://lis.rlp.cz/ais_data/aip/data/valid/a2-mt-radv.pdf

 

Please observe the HLV2T arrival. Between waypoints MT716 and MT715 the minimum flight altitude on the STAR is 4000ft. The minimum vectoring altitude in the same sector is 5200ft (5600ft during winter). So you must be able to tell Euroscope not to trigger warning when the aircraft is flying on the route at 4000ft, but to trigger a warning when the aircraft is vectored away from that route at 4000ft. Conclusion is that minimum altitude at route can be lower than MVA, because the route has protected buffer only +-1NM, but the MVA respect also obstacles which are far off the route. In this case the problem are mountains in the south most part of the MVA sector, which raise the whole MVA so high, while the terrain under the narrow route buffer is low and flat.

 

Also one more feature request: it would be great to define separate summer and winter MSAW values - because as shown in the chart, during winter the MVA altitudes are higher (because cold air correction, etc etc - altimetry stuff). So having a summer and winter value + changeover dates for MSAW would be amazing.

 

Pavel

Pavel Brodsky

VACC-CZ

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  • 1 year later...

Came across this topic again.

 

Also one more feature request: it would be great to define separate summer and winter MSAW values - because as shown in the chart, during winter the MVA altitudes are higher (because cold air correction, etc etc - altimetry stuff). So having a summer and winter value + changeover dates for MSAW would be amazing.

Honestly, I think this is a bit too much of detail for VATSIM. If one uses a tool like GNG to manage and create the sector file, it is easy to either provide one or another set of MSAW sectors for specific sector file release. It will anyway be difficult to ensure all controllers use the same MSAW altitude if there are more than one set, because not everyone might have updated his sector file or selected the correct set (if that would be an option).

 

I have to admit I was wrong before and it is definitely an option that a flight is below MSAW and everything is fine. So to make a bit of progress with the least required effort, but make the option at least usable in a certain way, I would propose the following functionality to be implemented. MSAW alert is triggered in case:

  • aircraft below an MSAW altitude valid for the current position
  • aircraft [Mod - Happy Thoughts]umed by the active controller or a handoff request has been received (can be an option, so MSAW alerts could also be selected to be triggered for any controller)
  • flight rules is IFR (includes that a FPL is required)
  • RAM detected or HDG [Mod - Happy Thoughts]igned
  • CFL is not (visual) approach

 

Gergely, you think this can be done with reasonable effort?

 

Happy easter to everyone!

Jonas Kuster Leader Operation - vACC Switzerland | www.vacc.ch

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