PPRuNe Forums - Flight Level, Transition Layer and when to use it

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- - Flight Level, Transition Layer and when to use it (https://www.pprune.org/private-flying/356814-flight-level-transition-layer-when-use.html)

Reading the above stuff does my head in :)

The answer must surely depend on whether one is trying to

1) answer an exam question (in which case I can't help because it will be heavily context and airspace/country dependent) or

2) is trying to fly safely.

On the 2nd one:

When outside controlled airspace, you can legally fly anywhere, at any height (subject to the 500ft/1000ft etc minimum rules etc) but fairly obviously you have to set the altimeter to either 1013mb (29.92") or the local airspace owner's QNH, according to whether the base of CAS is specified as feet or as a flight level.

If under an ATC service, and this includes flight in controlled airspace, you fly at a level/altitude and with an altimeter setting as negotiated with ATC.

Personally, when OCAS, I fly at "funny" levels e.g 3700ft because one is less likely to bump into somebody there. I would never fly at 2000ft or 3000ft for any length of time. But when approaching CAS and about to ask for a transit, then I sort myself out at one of these round numbers, to stop ATC wondering what the hell I am doing flying at 3700ft. So I might approach e.g. Solent doing my best to look good, at FL040.... only to have them grant me a transit at 4000ft on a QNH of XXXX :ugh: :) Like I say, you do whatever ATC would like you to do, and te rest of the time you do what you want to do.

Shall we start a thread on the minimum cloud separation, in different classes of airspace, in different countries, versus day/night? :) Oh and I nearly forgot... versus VFR/IFR flight.

172, I did try to stress that my answer was related to the UK, for the reason you mention. But I guess Pompy wants to get his head around the rules at home first.

If you take PompeyPaul's post and answer the questions he asks, as he asks them...

Quote:

"So when do you switch to FL ? Or don't you ever ? Why did the books seem to suggest about 3000ft you switched to FL ?"

Quote:

So when do you switch to FL?

Above the Transition Altitude (Whatever that is for the area you are in)

Quote:

Or don't you ever ?

Depends where I am... I fly out of Popham, and London TMA and Solent TMA are 6000ft, so hardly ever fly FL as I don't fly higher than about 4000ft, and by using altitude I can ensure I remain OCAS. I do though if I am above 3000ft and crossing the channel, just be sure to call VFR on you initial to the French otherwise they always seem to assume IFR with a FL.

Quote:

Why did the books seem to suggest about 3000ft you switched to FL ?

Because for most of the UK the TA is 3000ft. and normally outside CAS it is 3000ft unless a different TA is stated.... AND the less well known, (paraphrased) "Under Controlled airspace where the base is stated as an altitude" (E.g. under some of the Airways into and out of the London TMA whereby they are quoted at 5500ft. Would mean the TA is 6000ft - Otherwise you would be FL above 3000 and there would be no real way of ensuring you did not become a statisitic)