IFR use of handheld GPS

Bob Noel wrote:

It seems to me that you've already made up your mind wrt safety.

I have an opinion. That's not the same as being closed-minded. I'm
happy to hear the other side of the argument if you'd care to write it
down instead of just snapping back at me with one-liners.

wrote:

So you now assume that navigating direct with a handheld GPS is
dangerous? Why is that? I can understand why people disagree whether
its "legal" or not, but safety? And pushing RAIM won't convince me.
I've seen almost as many IFR panel mount units give unreliable data or
drop out unexpectedly as I have seen that happen in handhelds. And
just a couple of days ago someone related the story in another thread
regarding his glideslope instrumentation going bad and causing the
autopilot, on a coupled ILS, to reach DH some two miles early. I'd
call that a safety issue.


When you bring up the ILS G/S you are taking on precision vertical
navigation, which is a different issue.

"Light Tin" approach couplers and ILS G/S installations have been an
issue for as long as I have been flying.

So, just because someone couldn't manage marginal couplers or G/S
receivers/antenna installations is really not relevant to use of
handhelds for IFR.

And, here the issue in the thread has primarily been legal, not safety.

I have argued with Ron before that, given reasonable, personal integrety
checks, I would be safer flying a VOR overlay approach with my Garmin
296 than with a light tin VOR receiver.

wrote:

Bob Noel wrote:


It seems to me that you've already made up your mind wrt safety.


I have an opinion. That's not the same as being closed-minded. I'm
happy to hear the other side of the argument if you'd care to write it
down instead of just snapping back at me with one-liners.

It is perfectly safe to use a good handheld for en route in most
circumstances, provided the antenna is located correctly, and so forth.

En route RAIM is a very loose spec, compared to approach RAIM.

But, the issue here is legality.

Then, there is the question of having a current database, more for
safety than legality in this case.

In article . com,
wrote:

Bob Noel wrote:

It seems to me that you've already made up your mind wrt safety.

I have an opinion. That's not the same as being closed-minded. I'm
happy to hear the other side of the argument if you'd care to write it
down instead of just snapping back at me with one-liners.

Do you think that we should look for improvements in safety or are you
of the opinion that the level of safety of, say, 1950 is sufficient today?
(this isn't a one-liner - just starting the dialog).

--
Bob Noel
Looking for a sig the
lawyers will hate

I have argued with Ron before that, given reasonable, personal integrety
checks, I would be safer flying a VOR overlay approach with my Garmin
296 than with a light tin VOR receiver.

I won't disagree that when each system is working properly, an
approach with GPS (especially a moving map), is easier (thus perhaps
safer) than a VOR approach. But the point is that if a GPS satellite
malfunctions all bets are off. Hence the need for RAIM or equivalent.

Ron Lee

"Bob Noel" wrote in message
...

If you don't understand RAIM, then why bother asking about safety?


Nothing in his message suggested he doesn't understand RAIM.

"Sam Spade" wrote in message
newseb8g.176055$bm6.60789@fed1read04...

It is perfectly safe to use a good handheld for en route in most
circumstances, provided the antenna is located correctly, and so forth.

En route RAIM is a very loose spec, compared to approach RAIM.

But, the issue here is legality.

Then, there is the question of having a current database, more for safety
than legality in this case.


Legality isn't an issue either. Since use of a handheld GPS during IFR
enroute flight in US controlled airspace does not by itself violate any FAR
it is perfectly legal.

Bob Noel wrote:
Do you think that we should look for improvements in safety or are you
of the opinion that the level of safety of, say, 1950 is sufficient today?
(this isn't a one-liner - just starting the dialog).

--
Bob Noel
Looking for a sig the
lawyers will hate

Yeah, I agree. Safety improvements are great. So how is safety
improved by telling people with perfectly good handheld GPSs that they
must stay on the airways and navigate with their VORs?

In article .com,
wrote:

Yeah, I agree. Safety improvements are great.

The tone of your reply makes me wonder...

So how is safety
improved by telling people with perfectly good handheld GPSs

How do you KNOW that the handheld GPS is "perfectly good"?




that they
must stay on the airways and navigate with their VORs?

Who said they have to?

--
Bob Noel
Looking for a sig the
lawyers will hate

Bob Noel wrote:
In article .com,
wrote:

Yeah, I agree. Safety improvements are great.

The tone of your reply makes me wonder...

The tone is there because I'm still waiting to see why you think using
handhelds is unsafe. In many ways they add tremendously to safety,
especially the newer incarnations that depict terrain and weather. And
you probably agree that they are a great aid to situational awareness.
Why not, then, use them to help in certain navigation tasks as well?

Do you have data that shows that handheld GPS units are not more
reliable and dependable than the old VOR/DME/ADF system?


So how is safety
improved by telling people with perfectly good handheld GPSs

How do you KNOW that the handheld GPS is "perfectly good"?

Because the occasional failure is not a significant impact on safety.
Between the pilot and controller monitoring the flight, errors will be
caught. It doesn't have to be perfect to be "perfectly good", I guess
that was a poor choice of adjectives on my part.

How do you know any piece of avionics is working right? Some are more
reliable than others, but all can fail. Even panel mount GPS units
with RAIM. They can fail for various reasons that the RAIM algorithm
will not predict. It is supposed to prevent the pilot from using
erroneous data, and most of the time it probably does. But just
because they are "safer" than handhelds doesn't make handhelds unsafe,
doesn't it?

I'll agree that a GPS with RAIM is better than one without. Now, I
don't know the details, but I have read that WAAS has better fault
monitoring than standard GPS+RAIM. Does that mean that all those poor
sods out there flying IFR with their Garmin 430/530 units are being
unsafe?

And what about those handhelds that use WAAS? I don't know if they do,
but if they did have the full fault-monitoring capabilities, would
those be "safe" in your view?

that they
must stay on the airways and navigate with their VORs?

Who said they have to?

I was asking you a question. What is your view? If it is unsafe to
use your handheld to navigate direct, what are the choices that you
think are still "safe" for off-airway flights?

Peter