I think Russia was doing it not long ago, maybe still are? When used to the other way, seems a little bass-ackwards.
Russia definitely did it. So did most of the former SSR states. Almaty, Kazakhstan (very nice) used to be a regular stop for us between Asia and Europe. They did QFE
meters below the Transition Altitude. Our FMSs and autopilots only work on QNH
feet, so we had a chart that we would use to convert the QFE meter height given to us by ATC into QNH meters for the autopilot/FMS. It wasn't as bad as it sounds since there was usually just one altitude given to us below the TLvl. But, there are plenty of big mountains in that area, so in the weather, you'd always be double and triple checking your conversion... just in case.
I think the whole world should go to Standard above 180. No I don’t want to discuss the differences with 180 whether a low or high local altimeter setting.
Just use 180 everywhere, easy.
You can't just use FL180 everywhere. We don't even do that in the US.
I agree. As a 'murcan I find it odd that some countries have transition altitudes of 5000', 6000', etc... or sometimes transition alt (you mean transition level) is given by ATC (wTf?). So you end up with flight levels of FL80, FL100 .... bizzare.
18,000' everywhere! Murca!
For most of you all, it really doesn't matter. But there is a difference in Transition Altitude (TAlt) and Transition Level (TLvl). Transition Altitude is the highest altitude you can be assigned before going to QNE (29.92/1013). Climbing above the TAlt you'll set QNE. Transition Level is the lowest flight Level you'll be assigned on descent. Descending below the TLvl, you go from QNE to QNH (or QFE, but that's the exception).
Like mentioned above, in other countries the TAlts/TLvls are sometimes lower, and many times split. For example, in France, the TAlt is 5,000' QNH. So, on climbout passing 5,000' you'll set 1013 Hpa. The TLvl is "by ATC" and will come to you on the ATIS. Generally it's around FL060. So, on descent, once you pass FL060, you'll set the QNH.
Like I said above to
@sourdough44, you can't always use the same TAlt/TLvl. It's a safety issue, and we don't even do that here in the States. The TAlt in the US is always 18,000, but the TLvl can be higher... much higher based on the local altimeter. The difference is that in the US, the controllers take care of that for us, and we don't have to worry about it.
So, if you're landing somewhere in a low pressure area, and the local altimeter is 28.90, the lowest flight level you can be given is FL195, essentially making the TLvl in the US FL195. The reason behind the split TAlt/TLvls in other countries and the US is because if you have a plane flying around at 17,500 with a really low QNH set and another airplane at FL180 with QNE set, they could be a conflict, so when the local altimeter is low, they have to raise the lowest FL to keep that traffic separated from traffic in the area using QNH. [See 14 CFR 91.121(b)]
To remember which one is which, in TAlt the "A" points up, so you use that one in the climb out, and in TLvl, the "v" points down, so you use that one on descent.
Nah I love learning about this stuff. I'll probably never have the opportunity to what guys like Sluggo and Kayoh and Larry and others on this forum do for a living. But it fascinates me. So any opportunity to learn how the pros do it is not an opportunity I'm gonna pass up. 
