In article ,
"Steven P. McNicoll" wrote:

"Ron Garret" wrote in message
...

shrug So make the scenario on-airway.


On-airways flight doesn't require any VOR twiddling either.

Yes it does, just not as much. Are you a pilot?


Or have the radar fail.


Then the controller will issue a route on-airways or within normal navaid
usable distances.

And how will you arrive at an airway if you are not already on one when
the radar fails? Will you use your teleporter?


Or have the controller not paying attention.


If you're not prepared to trust the controller to pay attention you're not
prepared to operate IFR in controlled airspace.

It's an easy out to just assume that one of the components in the
failure chain is infallible. If that is the case then indeed there is
no risk. But it isn't, so there is.


Or have the pilot file /G.


Radar monitoring is still required.

Off-airways IFR flight was not made possible by the advent of GPS, it was
made possible by ATC radar.

I thought it was made possible by RNAV, but I confess I'm not an
authority. Do you have a reference?


Yes I did, though as I suspected it hasn't done any good. You seem to
have a different definition of "risk" than most people.


Ya think? State your definition so we can compare it to the dictionary
definition.

Risk (n): The possibility of suffering harm or loss

Taken from dictionary.com.

And yours?

If handheld GPS is not a risk then neither is AI failure. The two
differ only in their likelihoods; structurally the two situations are
identical. Both GPS and the AI provide information that can be wrong.
Both have backups that are supposed to kick in if the information is in
fact wrong. In both cases the backups can fail, or the pilot can fail
to use them properly.


I don't see a lot of similarity. The most difficult aspect of an AI failure
can be determining that it is the AI that has failed. If you're in solid
cloud and the AI and TC are providing conflicting information, how do you
determine which is incorrect? In a study done some years ago in a simulator
that situation resulted in a loss of control by most pilots in less than a
minute.

If your GPS fails and you drift off course the controller alerts you to the
situation, you don't have to figure out anything on your own.

Again, this assumes infallible controllers -- and infallible radar and
infallible communications equipment both on the ground and in the
airplane. If all these things were indeed infallible you would be
correct. But they aren't, so you're not.

I'm going to try to merge our two sub-threads he

Well, Ron, the fact of the matter is a failed AI is quite sufficient to
produce an unusual attitude.

If that were true then every instance of a failed AI would necessarily
result in an unusual attitude. (That is what it means to be a
sufficient condition.) But that is clearly not the case.

PPIASEL with just over 500 hours. I fly an SR22. I have also in the
past flown IFR in a 182RG/A both with and without a handheld GPS (yoke
mounted) and felt a lot safer on the whole when I had it than when I
didn't.


Was any of it logged in the US?

All of it.

Was any of it logged outside of MSFS?

I see that when logic and reasoning fail you, you revert to insulting
your opponent. So I guess I must be winning this argument.

So you're saying the hazard presented by use of a handheld GPS for enroute
IFR navigation in US controlled airspace is loss of rudder control. Is that
correct?

Not *the*, *a*.

You said use of a handheld GPS for IFR enroute navigation in US
controlled airspace is hazardous because it could compel the pilot to turn
off all his other avionics or jam the rudder pedals.

That is a caricature of my position.

And you think me an
idiot because I try to explain why that isn't so.

You have no basis for believing that I think you are an idiot other than
your own paranoia. I tend not to judge people so harshly. Very few
pilots are idiots (very few idiots have what it takes to fly a plane),
even though nearly all of them say and do idiotic things on occasion
(like calling their fellow pilots idiots) -- myself no doubt included.

Since you brought it up, this is my assessment of you:

On the surface you seem to be incapable (or unwilling) to grasp the
difference between a small or insignificant risk and a non-existent one.
But my guess is that deep down inside you do understand this, but your
ego simply won't let you admit it because you have dug your heels in so
deeply on this. The irony is that the difference between what you
actually say and the truth is only one little word. If you would merely
hedge your position a little bit by saying that there are no
*significant* risks associated with using a VFR GPS in IFR then everyone
will simply agree with you (or at least I will) and we can all stop this
silliness and go flying.

rg