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The Jeppesen and FAA IFR plates represent the same information in different ways. The FAA publishes its charts for free, but the underlying data that goes into the charts (e.g., exact coordinates of fixes, frequencies, etc) doesn't appear to be published in a structured format. The PDF files that the FAA publishes appear to be created using Bentley MicroStation, but do not seem to embed any useful metadata about what the various symbols mean.

Based on that preliminary research, I am wondering how Jeppesen creates their various charts, such as IFR approach plates? Do they simply take the FAA charts and manually create their own derived charts (which strikes me as tedious and error-prone)? Or is there some hidden repository of structured FAA data available somewhere that they use to create them?

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    $\begingroup$ The short answer is probably that they get it from here.And this question is very closely related. $\endgroup$ – Pondlife Dec 29 '16 at 16:47
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FAA/NACO charts aren't masters, either

The master form of a FAA instrument approach procedure isn't the FAA/NACO approach plate for that procedure -- that plate is a derived document, just like the Jeppesen plate for that approach is.

The master, instead, is kept by the FAA in textual form as a set of Form 8260s. These provide a precise, formulaic description of any FAA approach procedure -- they're simply not in a form that's at all usable in the cockpit.

An example set of 8260s for the (rather special) KASE LOC/DME 15 approach can be found here. Note that this contains exact records of fixes, governing obstacles, holds, and other procedure parts, as well as documentation about standards waivers and notes of changes.

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  • $\begingroup$ That's quite an elaborate (and unstructured) document! Do you happen to know how it relates to the Coded Instrument Flight Procedures (CIFP) database at faa.gov/air_traffic/flight_info/aeronav/productcatalog/… ? $\endgroup$ – marcprux Dec 30 '16 at 4:02
  • $\begingroup$ "The National Flight Data Center (NFDC) is one element within AJV-5 with respect to maintaining the National Airspace System Resources (NASR) database and for disseminating information relating to the NAS. NFDC is also responsible for maintaining proposed data within the AIRNAV database for the development of instrument flight procedures." Source: Order 8260.19, Flight Procedures and Airspace $\endgroup$ – mins Dec 30 '16 at 14:24
  • $\begingroup$ @MarcPrud'hommeaux: In addition of my previous comment: "The National Airspace Systems Resources (NASR) team currently provides [...] Process all aeronautical source data published by the NASR and IFP databases for inclusion in the Coded Instrument Flight Procedures (CIFP)" Source. $\endgroup$ – mins Dec 30 '16 at 14:37
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    $\begingroup$ Not only does Jeppesen create there documents from the same raw data that NACO uses (in the US), they provide charts, plates, and databases covering most of the world. That requires collecting the raw data in various formats from dozens of different governments and agencies around the world and converting it all to their standard on a 28-day update cycle. $\endgroup$ – Gerry Dec 30 '16 at 23:17
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Considering that Jeppesen provides their products in several different formats, such as the paper charts, their JeppView application for iPad EFB's, and database subscriptions for aircraft Flight Management Systems, it seems highly likely that they use a database of their own -- and a massive one at that!

Beyond what is publically available, they offer a service to major subscribers (i.e. airlines) to "tailor" some or even all of the approach charts. While they can't change the FAA's minimums in a way that makes them less restrictive, they can do other things with them. For instance, if Sky Air only flies aircraft that are approach category C, then the tailored charts might remove the Cat A, B, and D minima. Also, if they always use the altitude alerter in the aircraft for non-precision approaches, they might have Jeppesen round the non-precision approach minima up to the next 100' increment.

I've also seen tailored charts that address Category II and Category III approach minimums. The generic chart might show both Cat IIIA and IIIB minima, but if the airline was only approved for IIIA operations, the tailored charts wouldn't have the IIIB info. Or an airline that only used autoland would omit notes about using a HUD for approaches below Cat I, while an airline that only uses a HUD and not autoland could do the reverse.

When a published change from the FAA affects a point on the chart (say, a feeder fix to the ILS course itself), then every chart with that point will have to be re-issued, and that could affect dozens or even hundreds of charts -- and attempting to ensure that process works as a manual process would be nearly impossible. A database that includes the ability for a Jeppesen charting specialist to say, "show me every chart with the point 'JEBBB' on it" would make that process a lot more reliable.

When you see some of the new products that they have in development for the iPad, such as SID and STAR charts that are to-scale and geo-referenced -- allowing the magenta aircraft symbol to "fly" along the points of the chart -- and with significant terrain screened in as a dim underlay to the graphics, it becomes clear that they are only producing these sorts of products out of a database, and not created by hand.

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