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GAMEOVER
24th Feb 2011, 18:27
Hi All :)

A friend of mine was asked the following and we donīt know the answer.

Why is MEA at 25.000 FT over the Sea? In some places

Does anyone know the answer?

Thanks a lot?

mattpilot
24th Feb 2011, 18:50
Restricted airspace below?

Inadequate navigation signal reception at lower altitudes for the entire length of the airway?


Not sure, but those would be my guesses.

GAMEOVER
24th Feb 2011, 18:57
Thanks,

No restricted airspace.

I told to him that the highest point was within 5 NM from one of the navigational facility used for that long corridor, Airway over the sea.
But, Iīm not sure.

I think your answer is good.

seilfly
24th Feb 2011, 20:27
If it was closer to land, I would have suggested radio reception minimum altitude as the reason why, but recognizing todays navigation systems I guess navaids won't be recieved cross atlantic anyways.

Could it be the altitude floor of any airspace these routes pass through?
Or mabye because it is an upper airway, with upper airspace starting at FL245 some places... FL245 as the floor of upper airspace would give FL250 as the lower IFR flight level...

capt. solipsist
25th Feb 2011, 03:09
MEA is all about radio nav reception guarantees, save for restricted area instances.

sevenstrokeroll
25th Feb 2011, 04:08
you didn't say which sea...

if it is a sea, close to land, some limited radar coverage is available...MEA might be high enough to allow radar, radio nav, vhf com, and of course terrain clearance.

depends which sea

ant1
25th Feb 2011, 07:52
Flying an upper airway in a country where upper airspace starts at FL245?

9.G
25th Feb 2011, 11:12
from the same source jeppesen section enroute chart legend:
FL 250 MEA (Minimum Enroute Altitude) shown only when higher than floor of the high altitude structure. Nice to learn something new.:ok:

GAMEOVER
25th Feb 2011, 11:20
Hi Everybody :)

The interviewer didnīt say which sea, no details. I donīt know why.
I think that he wanted to see your knowledge developing different answeres and possibilities.

It was a question to get a position of Captain.

I think, there are many scenarios for that question.

:ok:

GAMEOVER
25th Feb 2011, 11:27
9.G I think you are right.

I have just checked it in my Jeppesen book.

Thanks :ok:

9.G
25th Feb 2011, 20:17
GAMEOVER, no worries mate. I recall flying with some of those bookworms which, I admittedly can be called as well, on a nice sunny day at FL 400 with limitless visibility. Just for fun I asked the guy if we could emergency divert to an airport at 10 O'clock seeing it both visually and ND so it's suitable for us. Guess what, the guy says NO WAY we don't have charts for that. Well, that's says it all, doesn't it? Visual means doesn't mean much nowadays, folks don't look outta the window much, pretty much same thing with the radar. I was wondering how guys flew with DC3? :ok: Use all of available resources including your eyes. :ok:

Microburst2002
26th Feb 2011, 18:10
The chart is a HI/LO or just a HI?

MEA is the minimum en-route altitude of an Airway.

Airways have lower limits (both upper and lower airspace ones). The lower limit can be arbitrarily set. Radio reception and obstacle only limit the minimum MEA.

Upper airspace airways are not necessarily superimposed on a lower airspace airway. If there is no airway below, the upper airway lowest possible MEA is the upper airspace limit. FL245 is the limit between upper and lower airspaces in many countries so I bet this is the case.