Oh dear, my second topic in 1 day!!! :Hypnotized:Anyhow, I use SimRoutes to figure out my routes, and, just today (like in my other post) I was doing KPDX-KSEA and it said that a possible route was RIVR6 BTG OLM6The thing is, on my FMC I have RIVR7, BTG, and OLM7. Why is the number different like that? Only yesterday I was doing KEWR-KPHL (both flights on VATSIM) and the controller told me EWR7 departure, but I only have the EWR8. Is my AIRAC outdated? I'm using AIRAC 1108. Thanks.

Yeap, the latest AIRAC is 1113, yours is 1108.

The reason the procedures have a lower number is because they aren't the latest. There used to be a notam on the simroutes site explaining why, but basically it's because the data used to be free and isn't anymore.

Oh dear, my second topic in 1 day!!! :Hypnotized:Anyhow, I use SimRoutes to figure out my routes, and, just today (like in my other post) I was doing KPDX-KSEA and it said that a possible route wasRIVR6 BTG OLM6The thing is, on my FMC I have RIVR7, BTG, and OLM7. Why is the number different like that? Only yesterday I was doing KEWR-KPHL (both flights on VATSIM) and the controller told me EWR7 departure, but I only have the EWR8. Is my AIRAC outdated? I'm using AIRAC 1108. Thanks.

Your AIRAC is indeed outdated. You can see the validity dates of your AIRAC on the INFO page of the FMC (the one yet get at start-up). Another way is by looking at the numbers, the first two numbers are the year and the second two are the cycle number. So AIRAC 1108 is the 8th cycle in 2011. As there is one cycle per month you can easily tell that 1108 is outdated (1113 will last until halfway through January, then we will switch to 1201).Offline an outdated AIRAC is not really a problem, and online often also not, since most procedures won't change with one cycle to the next.One thing to note is that the numbers for SIDs / STARs always increase with new versions, so even though your AIRAC is outdated you still have a later version of the SID and STAR than simroutes (RIVR7 is newer than RIVR6 and OLM7 is newer than OLM6).To answer your original question, the number is different because procedures are sometimes changed. The procedure then gets a new number (one higher than the previous version).John-Alan Pascoe

New procedure, new number. It's as simple as that.The current SID out of Dulles (IAD) is the Capital 8. When they update it, it'll be the Capital 9. After that, it jumps back to Capital 1, and back up the numbers to 9, and all over again.Any time something changes, they update the procedure number. In general, the SIDs never change too drastically, so if you have the EWR7 and it's now the EWR8, you're not too far off (HINT for the EWR8: Even if your FMC has it, it's not going to fly it correctly - read the chart, especially on the NY Area SIDs - www.airnav.com).While it's best to have the latest data, having an outdated version is better than having no data at all.

While it's best to have the latest data, having an outdated version is better than having no data at all.

And remember to always cross check the route the FMC gives with the charts, especially for crossing restrictions.John-Alan Pascoe

Ah. Thanks guys.