Originally Posted by
Capn Bloggs
I knew somebody would rip into me for that. Pull ya head in, Giggity. I never said I pass all responsibility for terrain clearance to ATC when they are radar-vectoring me. We also don't have access to radar terrain charts. Given the gung-ho attitude of some here "she'll be right, no hills around here that I can see", that's probably a good idea.
I don't understand then why you'd ever accept radar vector below MSA without the appropriate Radar Minimum Charts? If ATC clear you on a vector below MSA, how could you cross check the acceptability of that clearance without referencing it to a chart (SRA's excluded)? Surely, in that case you would have entirely absolved yourself of any terrain responsibility and be deferring straight to the last line of defence, the GPWS.
Originally Posted by
Capn Bloggs
Unless you're on radar vectors or a STAR, you ain't going below the MSA with me unless you're at the IAF. Weather in the way? Hold or go to your alternate!
If you're doing you own thing though, as it appears here, John Wayneing an orbit below the 25nm MSA because you're high and in the area of the holding pattern is not on. You're either in the Hold or your not.
Can't see the relevance of "500sqm"...
They're obviously not in the hold. They could ask for extended vectors, would that be your preferred option? It may be more or less efficient than doing an orbit but achieves the same thing. ATC won't (shouldn't - that's why you cross-refrence your radar vectoring clearances from the chart just in case) clear them to a level below MRVA based on their current position/future position. You can request an orbit, a turn, 10 more miles, or a loop if you like, ATC will either approve it or deny it. If they approve it, then surely it is a vector which you should treat the same way you ever treat a radar vector, cross-refrence it's validity against your charts, which i've shown are available (that's not to say the guy in OPs post had them). If these charts are not available in your part of the world, then I am with you, where you operate, you shouldn't ever descend below MSA unless flying procedurally.
The relevance was that 500sqm is a very large area, there will be many times that weather might appear inside one of these 25NM/90deg arcs. In that case, i'd assume most pilots would request a deviation to one side or another after first checking whether it was safe (terrain wise) and then passing that request onto ATC. ATC will either approve or deny that request based on the terrain, airspace, traffic etc. Using Flight Detents RNAV STAR 28 chart, if there was stationary weather at ETPAL i'd genuinely like to know what you'd do? Would your only option be to request direct to the hold and stay 8300ft till you get there, then descent to 6000ft in the hold and fly the approach after a couple of laps of the hold (assuming there was no other compatible procedure, for whatever reason)? I don't mean to be obtuse but I can see this as the only solution, at which point ATC will tell you to stay at 8300ft and wait a further 20 minutes so the other aircraft can pass underneath you.
In reality, every time I've flown this approach - although it's been a while - it was via that RNAV transition and ATC just issue speeds for spacing. We've simply planned to fly the thing conservatively and don't end up with this dilemma.