Trans Alt and Trans Level / QNH and QNE

[Apache 5]

I've got the rote definitions of trans alt and trans level down with a good deal of understanding BUT how do QNH and QNE relate?



Is this right: Trans Alt= QNH and Trans Level= QNE? (jeppesen says it is this way, "everything explained for the prof pilot" seems to indicate the opposite?!?)



It seems as if QNH and QNE appear on enroute charts and Trans Alt and Trans Level appear only on approach plates, is this correct?

Any comments would be helpful...prepping for an interview right now!

 

[DC8 Flyer]

Trans Altitude = Altitude with local altimeter setting where you set 29.92
Trans Level = Altitude with 29.92 where you set local altimeter.

I think most of Europe is usually Trans Alt of 5000 and a Trans Level of 6000. Iceland uses a Trans Level of 7000 and a Trans Alt (as assigned by ATC).

QNE = (Elevation) = 29.92 (I THINK!)

QFE = Field Elevation, or if you set your altimeter to a QFE setting, on the ground it reads zero

QNH = Height above. If you set your altimeter to a QNH setting you get the height above the pressure plane set in the kolsman window (standard US SOP)

http://www.auf.asn.au/groundschool/umodule3.html#altitude

 

[80/20]

Just think of QNE as 29.92 and QNH as local altimeter setting - nothing more to it.
What can be more confusing is questions about transition level, altitude and layer. This is more of an issue on international flights outside the US where the change to 29.92 often is not fixed at 18000’.

It is normally between 4000’ and 10000’ and separated by a transition layer of 1500’-2000’.



Example:

TL ---------------- FL 085 -------------- (change from 29.92 during descent)
(transition level)
↑

Transition layer

↓

TA -------------- 7000 ft --------------- (change to 29.92 during climb)
(transition altitude)