I am quite conscious of the altitudes one is expected to cruise at when flying cross country VFR (hemispheric rules)
But in practice, in Europe I almost never observe them because of:
3) cloud avoidance in a few or scattered layer (forcing me up or down, or simply making a non-standard altitude more convenient)
4) preferred altitudes on VFR routes giving other options
5) changes in heading switching you from one hemisphere to another (and not wanting to climb or descend 1000 feet for these doglegs)
I am generally careful to report my planned cruising altitude to whatever ATC I am in contact with (in part, so no one comes after me). I also tend to report changes in altitude. Most of the time, the person on the other end couldn’t care less; sometimes they give me a block; or say I can fly any altitude up to x-level.
Once earlier in my x-country days, I had a young sounding controller (I had just been handed off to) demand I make a call on the ground after giving me new altitude instructions and commenting that I was non-standard (I had actually confirmed my alt OK with the controller before) The issue was either altitude or minutes after sunset. The supervisor I called was most polite; asked me what time I had landed at the uncontrolled airfield (I flew a tight circuit and managed to get on the ground 29 minutes after sunset!); he said there was no problem at all.
FWIW most of my experience with ATC is highly positive; including situations where I am abruptly cleared (unasked) into space that I didn’t know I was going to bust.
I’ve been told off by ATC in the US while avoiding weather “Sir, in this country it’s customary to fly odd thousands….” etc., and am learning that hemispherical levels VFR are expected in South Africa. But in Europe? Never mentioned by ATC and certainly not mandatory in UK, where weather generally precludes it anyway. See SERA
Never mentioned by ATC
French ATC often mention it.
Never mentioned by ATC and certainly not mandatory in UK, where weather generally precludes it anyway. See SERA
It is mandatory by SERA “except where otherwise indicated in air traffic control clearances or specified by the competent authority”. Apparently the CAA has “indicated otherwise” for the UK, but that’s not generally the case.
Strictly speaking, you can‘t fly „non-standard“ altitude. If an altitude or a level is not available (be it for airspace, terrain, cloud, etc.) then it is not available, and if you can‘t fly the next (correct) higher one, then you have to fly lower. In some cases, this means you have to fly below the altitude/level where the semicircular rules apply.
In practice, yes, one often can‘t respect this rule all the same. And ATC\FIS is not air police, so they usually don‘t care.
This Wednesday, when I flew down the UK east coast, I changed from VFR to IFR several times, and accordingly, I should have changed altitude/level each time, but of course, I didn‘t do this. So let‘s say I remained IFR all the time.
In the UK, ATC don’t care what you do in Class G (in terms of altitude).
Often I am asked about my altitude so I reply with “4300ft” or some such (I always fly at +200/300 or +700/800) and it never draws a comment.
If a transit is asked for then obviously things change.
Outside the UK, ATC tends to expect you at the +500 altitudes if VFR. I wonder how this is squared up with the ability to fly in Class G (and even Class E) non-radio? Are these levels legally required, or just [ex WW1] “airmanship”?
I recall seeing a proof that flying at these +500 levels increases the risk. @bookworm will have the reference.
I changed from VFR to IFR several times
You were always VFR as far as “the system” is concerned
Are these levels legally required
They are legally required above 3000’ AGL unless the competent authority says otherwise or you — for controlled flights — are cleared for another level.
Flying in the US, as Aveling noted, better to follow the standard levels (for one thing, there’s a lot more traffic). Obviously, any transit of CAS is at agreed upon altitude.
In Central and Eastern Europe and the Balkans, traffic is rare and people don’t seem to care. Usually, there are good reasons why I’m not at the appropriate altitude. I’ve done little flying in the UK. Perhaps concerns arise with traffic?
better to follow the standard levels (for one thing, there’s a lot more traffic)
in the US and in general in Class E airspace – yes, and it is quite right that ATC pulls up people who don’t stick to them.
In Class E, the idea is that while in principle, only IFR-IFR separation takes place and IFR-VFR gets separated visually, but by having IFR flights at x’000s and VFR flights at x,500s there always should be 500ft between the two, allowing for some altitude deviations.
That limits IFR-VFR conflicts to climb an descent stages, and it make IFR safer. It, however, makes VFR less safe.
In Class G, however, semicircular rules are completely silly, random altitudes would be much safer, perhaps together with quadrantal rules.
And in the US, east of the Mississippi, you are generally in class E. There really is traffic, so I stay low or on the odd 500. But when you’re the only plane in a 20 NM radius, perhaps it’s quite sensible not to worry.