I’m writing in regards to the automatic route generation feature that Simbrief has. Using the latest AIRAC from a Navigraph subscription, all the available routing options should be visible within Simbrief. Unfortunately, however, I still feel like this feature falls short in some ways:
Although the routing feature does generate routing well in general, the following shortfalls are commonly seen:
- Planning incorrect SIDs/STARs for the type of aircraft (turboprop vs turbojet)
- Planning incorrect SIDs/STARs for capable equipment (e.g., when flying a CRJ-700 into KDCA, the autoroute generator gave me the NUMMY3 arrival (conventional nav) instead of the FRDMM5 (RNAV), even though they transitioned from the same enroute waypoints and terminated to the same runways and approaches).
- Directs are too long: the TC AIM section 220.127.116.11 and FAA AIP Section 5.3 have limits for direct routes in their airspaces, including time limits and distance limits. As far as I can tell, these directs have been exceeded at times: One example is KDCA to KICT, where Simbrief planned a direct of 367 nautical miles from TOY to ICT:
- Directs can sometimes violate the minimum 1-waypoint-per FIR/UIR: The FAA has an Enroute Operation handbook where it says (on page 2-25) that Random RNAV routing should have at least 1 waypoint for each FIR/UIR it crosses, and it must be within 200NM of the preceding FIR/UIR’s border. Once again, I’ve seen that violated a few times.
- Direct routings in Mexico: As far as I understand, direct routings in Mexico are prohibited: all aircraft must remain on published airways. However, a generated route from KSAN to MMUN generated random RNAV routing within Mazatlan and Monterrey airspace. Ideally, this routing should have gone from LA FIR to Albequerque to Houston to Houston Oceanic to Merida, staying in US Airspace until the very end rather than cutting through Mexican airspace:
There seems to be much better handling here, despite all the weird funky rules in EU airspace. Nonetheless, I see room for improvement:
- I generated a random IFR route from LIRF to UUEE in a CJ4. Although this was well handled, the IFPS validation still produced an error for staying on upper airway routing above FL330 (which I believe is the vertical boundary for FRA).
- I also believe that it doesn’t take aircraft navigation capabilities into account, or aircraft type.
- I’m not sure if this is already a factor in flight planning, but the FRA restrictions can be time and weekday dependent (such as CDR1, CDR2, CDR3). I don’t see evidence of it being taken advantage of, though I could be wrong since I have no definitive demonstration.
I regularly see airspace clipping. Although it may not be 100% forbidden in some regions (such as US airspace; flightplans won’t get rejected they’ll just get rerouted last second), it’s generally bad form to clip airspace (e.g. a 5 mile leg in the corner of a UIR). If it could be avoided, that would be awesome as well.