Someone with a little Python knowledge should also be able to parse actual procedure files (public domain) and turn them into a compatible files for FlightGear use.
For instance, consider the
www.airnav.com charts, which usually link back to the FAA d-tpp:
http://155.178.201.160/d-tpp/1712/A typical RNAV approach would be this (KSFO/28R):
http://155.178.201.160/d-tpp/1711/00375RX28R.PDFThis could be parsed by Python to extract the waypoints (radials, offsets), names and altitudes to be used by the route manager.
This would involve some Python/OpenCV or PDF parsing obviously, i.e. no Nasal -but other than that, it's a good way to ensure that up-to-date procedures can be provided without violating any licenses, and this could even be turned into a web-service