QNH in mexico

[Jerel 0]

I was flying a route into mexican airspace and remember in an earlier version of RC that when told to adjust altimeter settings the call was QNH but with RCV4 the call is in "US measurements". Has something changed with Mexican airspace, or do I have something not configured correctly?Thanks,

[jd 57]

i could be wrong, but i think mexican airspace, from an rc perspective, follows faa regulations. so 18000 would be the "transition altitude" and FL180 would be the "transition level"or in other wordsthe PCA starts at 18000jd

[PeteP 2]

Well spotted Jerel, I think you may be correct. I had a quick look at the file s4.csv where the centre information is kept and all the entries for Mexico are flagged as using FAA procedures. From what I can find on-line, although Mexican procedures are similar to the US, they do seem to use the term QNH rather than "altimeter" and although they use TA of 18000ft, there is a fixed TL of FL200 so ICAO procedures would be a closer match, I think.If you want to have RC use ICAO rather than FAA procedures, do the following:1. In your RC4data directory, find the file s4.csv and back it up.2. Open s4.csv with WordPad or Notepad - NOT Excel - and do a "Find" on Mexico.3. At the end of each Mexico entry, you'll see a single letter "F" indicating FAA procedures to be used. Change each one to a letter "I" to indicate ICAO.4. save the file, start RC4 and you should have ICAO procedures in the Mexico FIR.PeteEDIT: jd and I were obviously posting at the time time with two oposite views so you can take your pick. :-) PP

[jd 57]

i defer to the experts.be aware, by going with icao procedures, you will need to watch your transition altitudes on the controller's page, and watch for the calculated transition levels at the beginning of the flightjd

[Jerel 0]

If I go with ICAO for Mexico how do I "watch your transition altitudes on the controller's page, and watch for the calculated transition levels at the beginning of the flight"?What values do those need to be? TL @ 20000?Thanks Pete and JD for the information and help.Regards,

[jd 57]

probably need to familiarize yourself with international procedures, such as those on page 107 of the manual, and possibly the last tutorial which is a good tutotorial on the transition altitude/level nuances of flying outside the USjd

[PeteP 2]

Hi Jerel,If you change Mexico to "ICAO" as I described in my previous post, you won't have to set any values. RC has TAs for the Mexican airports in its database and will set them automatically. The program will then set an appropriate TL depending on the pressure (QNH) at the time when you click "Start RC". All you need to do is listen carefully to whether your clearance is to an altitude or a flight level and set your altimeter correctly. Your co-pilot will remind you when it's time to change from QNH to standard setting on climb and vice versa on descent by saying, "altimeter check".If you want to know what TAs and TLs RC is using, they're displayed briefly on advdisp when you start RC or you can minimise Flight Sim and refer to RC's "Controller Info" page.Pete

[John Burgess 0]

Hi Pete and Jerel,If the change is to cover the whole of Mexican airspace I think you also need to search for Mazatlan, Merida and Monterrey.For consistency the entry should also be changed from F to I in the z4.csv file.All the best,John

[PeteP 2]

Thanks, JB - I wondered if there would be more than the Mexico FIR to change and I forgot completely about z4. Oh well, I knew I should have left this post to the airspace expert! I hope I haven't confused Jerel too much. x( PP

[Jerel 0]

So I need to do the following:If you want to have RC use ICAO rather than FAA procedures, do the following:1. In your RC4data directory, find the file s4.csv and back it up.2. Open s4.csv with WordPad or Notepad - NOT Excel - and do a "Find" on Mexico.3. At the end of each Mexico entry, you'll see a single letter "F" indicating FAA procedures to be used. Change each one to a letter "I" to indicate ICAO.4. save the file, start RC4 and you should have ICAO procedures in the Mexico FIR.PeteAnd what else with the "z4" file?I lost the last part of that with the other three cities.Thanks,

[PeteP 2]

Sorry about the partial instructions, Jerel. As John has pointed out you need to change the "F" to an "I" in 2 different files. So, the revised instructions are:1. Open s4.csv and search for all the entries for Mexico, Mazatlan, Merida and Monterrey.2. Change each "F" (which you'll find at the end of each entry) to an "I"3. Open z4.csv and search for all the entries for Mexico, Mazatlan, Merida and Monterrey.4. Change each "F" (which you'll find towards the start of each entry) to an "I"That should do it.Pete

[Jerel 0]

I changed the files with Microsoft Excel 2003 and I am now getting a runtime error '9':RadarContact.rcv4module.read_airspaceI saved the files but Excel prompted me because I am using an older version so I saved without making changes to the format.Help!If possible, can someone send me the two files in a zip?jhayes26@midsouth.rr.combtw, I saw a Mazatlan Oceanic but I did not change that entry.I only changed Mexico,Mazatlan,Merida and MonterreyThanks,

[PeteP 2]

OK, Jerel, they're on their way to you. This time when you edit them please use Notepad, WordPad or a similar text editor and NOT a spreadsheet!BestPete