Just one for our ATC colleagues, if I do request a descent to below MSA in an area, what sort of response back would I expect ? Just a clearance without comment ?
I can only relate this question to my experience of being a controller in England. I have absolutely no idea how things work in Indonesia, or most of the world for that matter
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My guess is that this flight was being flown outside controlled airspace? If so, it is not being provided with an air traffic "control" service.
There are a few dependents on whether or not us controllers in England warn a pilot about descending below MSA outside controlled airspace (mainly down to the agreed level of service being provided which is normally respective with the weather conditions). However, imagining I'm providing a Sukhoi aircraft with an appropriate service outside controlled airspace and it requested/advised of descent below MSA, I would most definitely say something along the lines of:
"Caution, you will be descending below the MSA of _____ft. Taking your own terrain separation, descend at your discretion."