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NSEU
7th Jun 2010, 03:15
Found in a commercial navigation database...

La Paz
Transition altitude: 18000
Transition level: FL40

Can the transition level be correct? (there seems to be quite a spread between the two)

Thanks.
NSEU

babotika
7th Jun 2010, 03:29
Impossible. The transition level must always be above the transition altitude, and more importantly above ground level ... La Paz airport elevation is 13313ft ;)

Jeppy says the TA is 18000, TL "by ATC"

S.

NSEU
7th Jun 2010, 06:21
ooops... Thanks, Babotika.

Do Flight Management computers assign a default value for this (say, 18000'), or let you fill in the blanks?

Cheers.
NSEU

Bullethead
7th Jun 2010, 09:27
G'day NSEU,

The FMCs I've worked with have a default value of FL180 until you load the arrival for your destination and then should come up with the correct info from the data base.

It is displayed on the VNAV DES> FORECAST page.

Regards,
BH.

NSEU
7th Jun 2010, 13:27
Thanks, BH.

and then should come up with the correct info from the data base.

So, in the case of La Paz, I assume it would show only the default TL of FL180 and you would overwrite this manually when ATC tell you what the TL of the day is.

Cheers.
NSEU

Bullethead
7th Jun 2010, 14:27
G'day NSEU,

All the places I have operated to over the last 7+ years have a stated TL and I can't recall what the FMC comes up with in a place like La Paz. I don't think it matters much because I also can't recall if the TL information is used for any sort of alerting function, certainly not on the B767s I fly at the moment though it does say this, "The FMC uses transition level to change displays between FL and feet" in the B747-400 Ops Manual.

Regards,
BH.

ClimbSequence
9th Jun 2010, 02:58
The Default TL at FL180 is due to the floor of class A in the U.S. airspace

muduckace
9th Jun 2010, 04:14
May be a querk due to field elevation....