Mxsmanic wrote:
VOR-DME writes:

In fairness to MX I think he meant that in the event of GPS unavailability,
airliners would be able to resort to their INS navigators, which small planes
do not have.

Yes.

I am not sure though that airliners will continue to be equipped
with INS systems after NextGen implementation, and even if they are this is
not good enough, as it cannot reliably provide better than RNP 1.0 and has no
approach capability.

That is one of my concerns also.

Many were hoping that LORAN-C would be retained and even
developed as a backup, but that was dashed recently when the system was
definitively abandoned.

Thanks to the same reckless policies that may decommission VORs and ultimately
ILS.

VOR’s are costly to maintain, and the FAA wants to
move away from them as quickly as possible (going back to my statement that
Victor airways are obsolescent and pilots so equipped should be filing \G as
much as possible already).

Safety is expensive. If you don't care about safety, you can save a lot of
money.

VORs can be used for RNAV, too. Flight management systems already do this,
since they use a blend of navigational aids in order to provide a more
reliable and precise position for the aircraft.

It could be that the best backup for GPS will be other satellite-based
structures, GONASS or soon to be GALILEO.

They all have common failure modes and vulnerabilities. A solar flare could
knock them all out at once. The only way around this is to have alternate
methods for navigation, such as VORs.

You have no clue what the jamming susceptibility of modern GPS is or what
features exist (current and planned) to thwart it.

In reality, jamming effects a small area and is a real concern only to the
military which would expect jamming in the area of enemy targets.

A solar flare large enough to "knock them all out at once" would also take
out a lot of other stuff making the lack of GPS a minor issue.


--
Jim Pennino

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