PFD barometric settings transitions altitude error in descend

[armengol 0]

Situation: set transition altitude at 6000 feet (or any altitude below 18000 feet)Ascent: above 6000 feet, PFD display numerical settings in amber. If press STD, PFD display "STD" in green. Descent: below 18000 feet, PFD display "STD" in amber. Josep

[aentwis 61]

Thanks Josep, I wanted to note this too. Let me word it differently: Regardless of the TA setting on the CDU, on ascent the annunciation of yellow STD on the PFD occurs when passing through the set TA, as per the real world aircraft no doubt. ON descent, however, the TA seems to be hardcoded as 18000 (US), regardless of what I set as TA on the CDU. STD changes to yellow as soon as I pass through 18000 on descent. I understand that there is no place on the CDU for different TAs for departure and arrival, as there is on the MD11... Andrew

[Not30Wagain 1]

Guys, It's TA on the way up and TL (Transition Level) on the way down. You adjust it on the VNAV DES FORECAST page (VNAV DES page press the FORECAST button).

[FLEX1978 371]

Same as the 747-400

[aentwis 61]

TA is fixed for an aerodrome, region, or country. TL varies according to air pressure to guarantee vertical separation from the QNH altitude. The MD11 has the ability to set different TAs for the departure and destination. I leave the London TMA with a TA set to 6000'. I fly over to Germany, where the TA is generally 5000'. Is is correct for me to state that the Transition Level is the first available flight level above the TA that may be used? Thanks for the info concerning the forecast page... back to the FCOM! :) Andrew

[armengol 0]

Thanks at all about us!

[g_precentralis 191]

TA is fixed for an aerodrome, region, or country. TL varies according to air pressure to guarantee vertical separation from the QNH altitude. The MD11 has the ability to set different TAs for the departure and destination. I leave the London TMA with a TA set to 6000'. I fly over to Germany, where the TA is generally 5000'. Is is correct for me to state that the Transition Level is the first available flight level above the TA that may be used? Thanks for the info concerning the forecast page... back to the FCOM! :) Andrew

And TL is fixed to aerodrome, region, or country too, but TL is not fixed level, it can float according to local pressure. So, TL can (usually) be 1,2 or 3k higher than TA, in order to maintain minimum of 1000ft separation. However there are exceptions, where TL is fixed, and TA can float (you can see that on any airport chart, TA 10000, and TL by ATC, or for exceptions, opposite: TA by ATC, TL FL120). Lj. Prodanovic

[beachdog2001 17]

Some charts will even specify different TL's depending on the existing barometric pressure. Pretty helpful actually.

[scandinavian13 5,189]

You can also set a default per aircraft in the settings, I believe. That should cure it on the way up and the way down.