Flight Level (FL) question

[Daveroo]

ok i admit i dont know much about the instrument flying and all that...i dont use autopilot or follow the "real rules"...i take off and fly VFR and dont even use the ATC and i fly without any AI traffic...BUT i want to change all that...one step at a time though.......

i purchaced dispatch planner X ,i set up a flight from KAUN (auburn ca) to KBAB (beale AFB) 27.9 air miles west of KAUN,it said to use "FL330" now this through me for a loop because i thought this meant 33,000 feet...but as ive thought about it...it has got to mean 3,300 feet as i doubt you could take a cessna 206 to 33,000 ft and back down in 28 miles...and if you can....wouldnt that be a bit excessive?
anyway...how do you "read?" flight levels?
FL340? ect or FL3400? if there is sucha thing?

[Ferry_vO]

FL330 is 33,000 feet, FL33 would be 3,300 feet.

:)

[falcon409]

ok i admit i dont know much about the instrument flying and all that...i dont use autopilot or follow the "real rules"...i take off and fly VFR and dont even use the ATC and i fly without any AI traffic...BUT i want to change all that...one step at a time though.......

i purchaced dispatch planner X ,i set up a flight from KAUN (auburn ca) to KBAB (beale AFB) 27.9 air miles west of KAUN,it said to use "FL330" now this through me for a loop because i thought this meant 33,000 feet...but as ive thought about it...it has got to mean 3,300 feet as i doubt you could take a cessna 206 to 33,000 ft and back down in 28 miles...and if you can....wouldnt that be a bit excessive?
anyway...how do you "read?" flight levels?
FL340? ect or FL3400? if there is sucha thing?
Daveroo,
ATC can be "quite excessive" just in it's own right, lol. In fact FL330 is 33,000. I believe the use of the word FL (flight level) is restricted to calling altitudes above 18,000. Below 18,000 you would refer to say 10,000 feet as "climbing to one zero thousand".

You may be able to set a predetermined altitude with that software. In other words, you set the altitude in the program and then ATC will go along with that altitude. If not, comply with the call to climb to that altitude and then request a lower altitude. They usually comply with that as well.

[SkippyBing]

FL330 is indeed 33,000ft. 3,300ft wouldn't really be a flight level as they're generally round thousands of feet or +500ft e.g. 28,000ft = FL280, 25,500ft = FL255. I'm not sure how the +500' are handled in game, generally they're used outside controlled airspace in the UK where you fly tracks between North and 089M at odd thousands of feet, West and 179M at odd thousands plus 500', South and 279M at Even thousands etc. Other countries have various methods of handling it, e.g. in the US it's odd thousands between North and 179M and evens between South and 359M.
The flight planner may be ignoring aircraft performance when setting flight levels, I don't think many civilian aircraft could achieve FL330 and back in 28 miles. Interestingly the diversion procedures for the RN's Jetstreams is to climb until the midway point and then descend as it's the most fuel efficient profile, there is a flight level given but it's unlikely you'd actually reach it even if you end up diverting to Valley (from Culdrose for those who aren't as familiar with the UK's flying system as I am!).

To add to what Falcon said, in the US (and FSX which is basically US Flight Rules throughout) below 18,000' you're flying at altitudes which are read as 'Nine thousand feet' and you should have the regional pressure setting on the altimeter, above that you'll be on the standard pressure setting of 1013mb/29.92 inches of Mercury and fly at flight levels. In the UK* this happens above 3,000', or the transition level, other countries have different heights for this to happen, there are various publications that detail what the differences are between countries, generally referenced to the country they're published in.

*Apart from Scotland where the mountains get in the way, I think it's 5,000' there but as I rarely fly above 3,000' in real life anyway it's never cropped up.

[dhl1986]

Flight Level is based on standard pressure 29.92 for high flying traffic, 18,000 and above. Add two zeros to get your altitude, for example FL330 = 33000, FL017 = 1700 (although you would never hear it referred to as that)

I believe the main reason for FL is to avoid complications for fast traveling aircraft flying through different pressures, which could be a major problem for obvious reasons. That said, I am far from an expert on this subject.

[falcon409]

Ok Daveroo,
I looked at the screenshots over at Simmarket on this program and you have a tab marked "Basic Flight Info" and that tab appears to allow you to set all the flight information to include altitude and airspeed. If that is the case, then you can set your own altitude prior to engine start and ATC will read the information out of your planner.

[IanP]

Just to correct a few people slightly, flight levels are used above what is termed the "transition altitude" (from altitude to flight levels). In the majority of Europe, including the UK, is actually 6000' (FL060). A lot more of the world standardised on the US value of 18,000'/FL180, while in certain places, it is measured in metres rather than feet and doesn't translate at all well.

At certain locations, you will find the transition altitude varies anyway, due to high terrain (flight levels can only be used above Minimum Safe Altitude anywhere). It should be able to be ascertained by looking at airfield charts, which should always show the transition altitude for that area somewhere - on the ones I have, it's in the top bar of the general aerodrome information page.

[SkippyBing]

including the UK, is actually 6000' (FL060).

In the UK it's 3000' apart from certain exceptions listed here: http://www.nats-uk.ead-it.com/aip/current/enr/EG_ENR_1_7_en.pdf

[IanP]

Not according to the IMC manual in front of me that says it has changed...

But then since when have CAA resources agreed with each other? :d

[SkippyBing]

Genius! I know they've been talking about making the TL uniform across the UK/Europe but I didn't think they'd actually done it yet. I mean after the mass education programme about the change from FIS/RIS/RAS to Basic and the two I haven't used yet, I figured there might be some sort of promotion!

[nio]

But then since when have CAA resources agreed with each other? :d

You kind of hope they might!

best

nio

:isadizzy:

[SkippyBing]

You kind of hope they might!

But that would restrict their flexibility!
I've been searching their website and the most recent document I can find that refers to TA is from Mar this year and says pretty much the same as my previous link, you'd think they'd make something like this a bit easier to find!

[IanP]

It's the IMC section of an Air Law book, and it's dated as reprinted in 2007, so I'd guess that it's probably a cock-up on their behalf (kind of silly in an air law book!) and go with NATS... They're the guys who enforce du roolz, so you'd hope they'd be right.

Unfortunately, nio, the CAA and NATS websites are somewhat notorious for inconsistencies - or they were anyway. That's why I normally rely on what books and issued paper say. However in this instance it looks like the book is wrong. I'll verify that when I get chance because I thought it had changed. It's a good job my IMC is no longer valid!

[SkippyBing]

Hmmm, interesting as it was definitely 3000' in '07 as I was in a flying job at the time and even I would have noticed that! From my reading around it looks like there are moves to standardise it across Europe at 10000' but how long that'll take is anyone's guess!
I believe the lower TAs are a hangover from the days of unpressurised transport aircraft as a lot of the air traffic never really got that high anyway (not good for the passengers and piston engines are generally better lower down anyway) and it needed to be at a height that would capture the majority of the air traffic. Obviously as aircraft developed it became less useful but there was no real pressure to change it.

Edited to add, I've just spoken to a mate who's in a flying job at the moment and he confirmed it is still 3000', and then asked if I didn't have better things to worry about on a Sunday evening!

[falcon409]

Okay Daveroo,
Given the content of your original question, and the volumes of information in this thread thus far you should be either totally confused or packed with enough information to keep you busy for years, lol.

If you fly primarily inside US borders for the most part the the phrase "flight level" is used to call altitudes at 18,000 or above. It is not used below 18,000. The rest you can glean from listening to ATC as you fly using your newly purchased software. Enjoy your flights.:salute:

[Daveroo]

thank you everyone...yes i do unnnerstand now...i get it.....lol

[falcon409]

thank you everyone...yes i do unnnerstand now...i get it.....lol
lol, good. . .have fun with all your new-found information.:salute:

[rvn817j]

While in U.S. Navy training, check list (always used) says when flying through 18,000 set altimeter to 29.92 (two niner niner two) (that is the number shown in the Kollsman window). Below 18,000 the Kollsman window is set to the local barometric pressure given to you by ATC or obtained from a local radio source if flying VFR. Once 29.92 is set passing through 18,000 you are in the 'Flight Levels'. [Never flew over continental Europe, so I have no clue what altitude is the transition altitude.]

[TeaSea]

The purpose of setting the altimeter (barometer) to standard pressure being, that while everyone might be wrong about their actual altitude....they will all be wrong together, which means good separation between traffic.

After 18,000 the altimeter (barometer) becomes pretty much useless....not enough pressure to keep it going. That's why the TA in the U.S. is at that level.

[fliger747]

I know from personal experience the altimeters work quite well from baro pressure through 45,000'.... Even the youtoo guys use them up into the 70's.

Many countries use quite different transition levels, some such as Netherlands use between 4000 and 5000 ft depending on the sea level pressure and whether you are climbing or descending. Ohter factors such as airport density, size of country and treeain can enter into the altitude selected for transition. In China and Russia it is metric....

T

[viking3]

With the advent of RVSM(Reduced Vertical Seperation Minimums) the altimeters are even more accurate, with errors of say +/-50 ft at 40,000 depending on the airframe. The old standard was 200 ft. at 20,000. Those figures are rough numbers but you get the idea. Pitot-static tests got to be a lot more finicky with the advent of RVSM. I had to get FAA signing authority in order to sign out Jet Blue checks.

Regards, Rob:ernae:

[SkippyBing]

After 18,000 the altimeter (barometer) becomes pretty much useless....not enough pressure to keep it going. That's why the TA in the U.S. is at that level.

Err.. it's still working perfectly well, you've just set a different reference pressure. I've read elsewhere that 18,000' was chosen as it's Mt Rainer plus a bit so there's no danger of flying into the ground with 29.92 set.

[TeaSea]

Then I stand corrected and defer to experience -- since I'm certainly not going to go jump into my Archer II and try to climb to 45,000 to check (it would get too cold).

In my defense I have been taught this from differing sources....but I now recall that my HALO jumping buddies treat their barometers with an almost religious reverence, and I know they often exit above 18,000 feet. And the Rainer thing sounds just perfectly plausible.

BUT, Mt. Whitney is the tallest Mountain in the lower 48, at a little over 14,000 feet. Rainer is shorter (by just a few feet I think). McKinley/Denali is over 20,000 .... so if you thought you were in Iowa at 18,000 but were in fact over the Alaskan interior...you would still be at risk.

But I think if you were that lost, your main issue wouldn't be terrain. Which brings us back to an earlier theme (why 18,000 feet?).

Did we ever answer Daveroo's question?

[fliger747]

One night many years ago we got a direct from Barrow to Anchorgae in C-130 (winter-night) and used the radar to home in over the summit of Denali at FL 250..... radar alt read 1200 ft.... Cold and low, look out below....

Cheers: T

[SkippyBing]

BUT, Mt. Whitney is the tallest Mountain in the lower 48, at a little over 14,000 feet. Rainer is shorter (by just a few feet I think). McKinley/Denali is over 20,000 .... so if you thought you were in Iowa at 18,000 but were in fact over the Alaskan interior...you would still be at risk.

But I think if you were that lost, your main issue wouldn't be terrain. Which brings us back to an earlier theme (why 18,000 feet?).I think 18000 feet is chosen as it'll give you adequate clearance in the worst case scenario, i.e. flying FL180 with very low pressure, on a very cold day with an orographic low caused by wind blowing over the highest point of land, all of which could rapidly eat into the 4000' between you and the top of Mt Whitney. As in the example above.
Bear in mind if you're flying on 29.92inHg/1013mb you've no easy way of comparing your height to that of the surrounding terrain as you're no longer using the same reference (mean sea level). Once you've chosen that altitude then applying it to the whole country simplifies procedures for everyone, especially if you're flying cross country. Compare this to the UK where some areas of the country have a different TA to others, no one's ever been so lost that it's been an issue, but why overcomplicate things? There is a CAA paper on the web which proposes raising it to 10000' across the UK/Europe for that reason.

[TeaSea]

I spent about 15 minutes today at the office arguing the 18000 foot transition with two other pilots. What amazed both of them was that there might be a differing standard in Europe (all of us have lived in Europe for long periods of time, although we never flew there).

One thought was that there might be different altitude due to the shorter distances normally flown on the European continent.

I've no idea, but it was a nice break from work.

[viking3]

The only fact? I know of that is mayyyyybe relevant is that supposedly half the atmosphere is below you at 18,000 ft. Perhaps they thought the margin of error would increase above that.... or am I just blowing smoke.:kilroy:

Regards, Rob:ernae:

[bstolle]

E.g. in Europe the TA / TL depends on the obstacles around the airport.
So even in the same country these are different.
E.g. in Austria, Innsbruck (LOWI) has a TA of 11000ft and at 1013hpa (29.92) pressure the TL is FL130.
In Linz (LOWL) the TA is 4000ft and the TL is FL60.

As a European one needs to get used to the fact that (e.g. in Canada) you sometimes switch to local pressure still 150NM away from the airport and at 32000ft (during the descent).

Regards

Bernt

[fliger747]

If one is going to have a continuous descent from cruise to below the transition level it is permissible to set the governing local altimeter, however this is usually not done as an intermediate leveloff is always possible, often likely.

T.