Originally Posted by
FlyJSH
Considering that satellites can be affected by solar flares, hopefully not very soon.
Now, go back to sleep
Lots of things can happen to satellite signals. Same thing with VORs and NDBs. If you can do an RNP approach without an underlying NAVAID, why would you require it when flying a VOR or NDB approach and you have RNP capable systems on board?
Originally Posted by
USMCFLYR
As to your other question, it is at least partly because not everyone is using RNAV. The NAS has to support ALL users - not just the airlines. Also - as you well know, GPS can be jammed and also has periods of unavailablility. Legacy NAS systems often backup those procedures.
For a more legal interpretation of the issues and why the FAA cares about this or that - I'd have to refer you to the policy makers. I am part of a flying crewdriver that makes sure things are working according to the tolerences set by those policy makers and to find problems in the system, and then in conjunction with other supporting players, we fix the system and ensure that it is operating back up to standards. Here is a blurb of our mission statement:
I just noticed the second part of your reply. Thanks.
Do you think with the invention of GPS and RNAV systems, the costs of maintaining all of those NAVAIDs outweigh the benefits?
I understand a lot of people use them, especially the DOD.
I think it would be cheaper for the government to pay and upgrade all the airplanes without RNAV capability, than it would be to keep managing these NAVAIDs. Now we are paying for both systems when only one is required.