Altitude deviation above TA/TL

[Guest paulmadejong]

I've noticed quite a deviation between my FL and actual Altitude when flying on standard QNH (1013) above TA or TL. Last, I was flying FL360 while my actual altitude was 36400ft.Also during approach to EHAM (TL035) I was cleared for FL050 which I did, but my actual height was 5500ft, als noticed bij Approach in IvAc (IVAO ATC client). In Forecast settings the TL was set correctly.Is this a bug in FS/PMDG or am i doing something wrong?Paul

[CF104 0]

Hi Paul,What you are seeing is uncorrected pressure altitude above TA/TL and is correct. Under most circumstances, the pressure altitude at 29.92 (1013) will not match true altitude.Cheers,JohnBoeing 727/737 & Lockheed C-130/L-100 Mechanichttp://www.precisionmanuals.com/images/forum/ng_driver.jpg

[Guest paulmadejong]

John, Yes I know, but I always thought that lowering the TL with increasing QNH was due to lower the different between heights above and below TL.The difference of 500ft. just a bit above TL is, what I think unworkable for approach. Is this happening realllife as well?Paul

[Mats_J 2]

Paul - If you got cleared to FL050 and was flying on STD pressure you were correct. If you on the other hand was cleared to 5000 you should've gone QNH pressure, and the altitude reported by FS and the NG should've matched. In the first case the TA was below FL050 and in the second case TA was above FL055. IIRC FL055 is a common TA if the QNH isn't extreme.Hope it helps,

[Guest paulmadejong]

In this specific case TL was at FL035 QNH 1032, TA was 3000ft.Ussually the TL is between FL040-045. In this case the difference between FL and actual height isn't this big or even noticeable, so I'm thinkin I did something wrong (I'am certain that I was flying on 1013 above TL/TA) or something else.Paul