Because there wasn’t already enough info on your Sectional Chart
Since the FAA was only able to cram five thousand and one pieces of info onto your sectional chart, they decided that they wanted to give you even more information and they thought the best way to do this was through a Chart Supplement (note: the Chart Supplement used to be called the AFD or Airport Facility Directory, it’s the same exact document, but we have a new name for it. Please use the proper name of Chart Supplement when referring to it).
The helpful info you will be able to find on a chart supplement includes:
- Runway Lengths
- Types of Services at the Airport
- Telephone Numbers
- Nav Aid Information
- Tower Hours of Operation
- General Airport Layout
- Everything else you could ever hope to know about the airport. If you’re looking for information about an airport, chances are it is in the Chart Supplement.