Ongoing QNH problems

[Guest mikealpha]

Got a new one yesterday after the already reported problems with Approach occasionally giving me wrong QNH.On the way to Stockholm ESSA I got nagged I didn't make my crossing restriction. Which was "cross 40 NM from Arlanda VOR at FL 110". I clearly was at FL110 slightly before that 40NM, so I first thought it was a distance problem and just continued. RC4 let me fly without coming back, after a while I opened advdisp and noticed ARL VOR at the first line with an altitude of 11600. Would have corresponded to the local QNH, but the transition level was set to 5000. Can't be having to set local QNH at FL110. However, I decided to descend and when arriving at 10400, RC4 continued with giving me headings, now back to the Airport.Mike

[PeteP 2]

>>after a while I opened advdisp and noticed ARL VOR at the first line with an altitude of 11600. <

[Guest mikealpha]

Pete,arghhh, what a rubbish I wrote. Sure that was the frequency. LOL.Certainly you are right, the transition altitude was 5000. I couldn't imagine any QNH though, that would make that a transition level up to 11000 :-). Just checked my notes, QNH was exactly 1000. So RC4 nagged at me at 40 NM, because it must have thought I had descended through the assigned flight level.I'm using that particular plane for all of my RC4 flights and I'm 100% sure the altimeter was set at standard pressure. I had double checked it when I got that complaint from the controller. And still weird, RC4 let me alone until approx. 35-40 miles away from the active runway in other direction. Seemed to me I have woken up the controller again when I decided to descend myself.The whole story somewhat fits to the QNH problems I occasionally get on approach.Mike

[PeteP 2]

OK, Mike, with a QNH of 1000hPa, FL110 would have been at approximately 10600ft but if you're certain you had 1013 set on your altimeter, that shouldn't be the problem.If you'd like to post your flight plan here, I'll try and fly it later today and see if I get the same problem.BestPetehttp://www.jdtllc.com/images/rcv4bannerbeta.jpg

[Guest mikealpha]

Ok, here goes. I'll also repeat it today.EDDH to ESSA@33000 (Alt1- , Alt2-) / LUB.AMICH.MEGAR.GES.LEBDA.MOSIN.GORAX.KEMAX.NEXIL.ROXEN.BEDOS.MIKNA.PELUP.TRS.TEB.ARL. *RVSMTEB is the IAF for ESSA. ARL, the ESSA airport VOR, is somewhat artificial in that flight plan to get the above mentioned crossing restriction.Aircraft used : LAGO Maddog MD82Mike

[PeteP 2]

Thanks, Mike. I understand the use of ARL - I do exactly the same myself to get a realistic crossing restriction clearance. I'll probably fly it this afternoon and I'll get back to you.BestPetehttp://www.jdtllc.com/images/rcv4bannerbeta.jpg

[PeteP 2]

Mike,I've just finished flying your plan but, unfortunately, I couldn't replicate the problem so I'm afraid I don't have an answer - this time. However, please let us know if the problem recurs and we'll try again to trace it.BestPetehttp://www.jdtllc.com/images/rcv4bannerbeta.jpg

[Guest mikealpha]

Thanks Pete. I couldn't replicate it either, all OK today. But today it was a different QNH (1019) and a different runway, so who knows. Which real weather program are you using ?Interestingly, I had a look at my flight plan sheets and I noticed those where I got wrong QNH were values below 1013. However, I'll continue to observe if that's really a tendency.Mike

[PeteP 2]

Mike, I usually use Active Sky but because I wanted a specific QNH, I just used the built-in user-defined weather for this flight.Petehttp://www.jdtllc.com/images/rcv4bannerbeta.jpg

[Guest mikealpha]

Got another weird one yesterday on the way to Copenhagen EKCH, coming from the south, leading to a more or less straight in to Runway 4L. Crossing restricton was 40NM/FL120 from KAS VOR. Approach let me fly for another 10-12 miles, then fired FL90 and 2000ft at me without taking a breath in between. So I heard "me" acknowledge two altitudes in a row then, quite funny. What followed was a LOC intercept at 20 NM and approx. 8000ft AGL. Probably you guys have a hard time to believe such reports, seems it's difficult to reproduce when real weather (ASV6) is used. Other day, other conditions. Would be nice to have a kind of RC4 Black Box, which logs the entire flight with maybe the following infos :Time - Instruction/Acknowledgement - Plane Lat/Lon, Altitude, Heading, Speed - QNH and whatever would be interesting.Mike

[John Burgess 0]

Hi Mike,We do have a debug option which logs many things. The trouble is the log files tend to end up being huge if their is much ai around!All the best,John