IFR with a VFR GPS

"Jose" wrote in message
news

What was the cause of that crash? Was the VFR GPS giving erronious
information? Was it hard to use, not being attached to the plane? Was
the pilot unfamiliar with the device? Was the approach even in the
database?


http://www.ntsb.gov/ntsb/brief.asp?e...23X05372&key=1

The NTSB determined the probable cause to be the failure of the pilot
to follow the published instrument approach procedure resulting in an early
descent into the tower. Why conclude the pilot believed he was someplace
other than where he was? Why is that more likely than just a descent below
the MDA?

Jose wrote:

What was the cause of that crash? Was the VFR GPS giving erronious
information? Was it hard to use, not being attached to the plane? Was
the pilot unfamiliar with the device? Was the approach even in the
database?

Well, the official, sterile probable cause reads:

"The failure of the pilot to follow the published instrument approach
procedure, which resulted in an early descent into an antenna tower. A
factor was the low ceiling"

Of course, all of those factors you mentioned certainly are possible, too,
but not provable. A clue to these other factors leading to this accident
was that the aircraft was one mile to the right of course at the IAF.

I recall reading an accident analysis article of this crash (I forgot which
of my monthly periodicals it was in) a few months ago that went into more
detail about the pilot flying an IFR approach with a VFR GPS.

--
Peter
























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"Peter R." wrote in message
...

Well, the official, sterile probable cause reads:

"The failure of the pilot to follow the published instrument approach
procedure, which resulted in an early descent into an antenna tower. A
factor was the low ceiling"

Of course, all of those factors you mentioned certainly are possible, too,
but not provable.


Nor is the NTSB's probable cause.



A clue to these other factors leading to this accident
was that the aircraft was one mile to the right of course at the IAF.


But "just slightly left of the approach course centerline" when it struck
the tower.

Gerald Sylvester wrote:

I can definitely see how a VFR GPS is useful when flying enroute and VMC
with loads of VOR's for use as a backup (err, primary navigation). To
do it, single pilot, in IMC, just has many single point failures or
where you have backups but requires a lot of work to get positively
established/stabilized again.

How does a handheld GPS have more SPOFs than a panel mount IFR certified
GPS? I would submit it has less because with a handheld electric power
is no longer a single point of failure like it is with a panel mount
(assuming you have a power adapter to plug it in and fresh batteries in
case you lose electric power).

The only legitimate argument that can be made is that the panel mount
GPS has an external antenna and the handheld relies on one mounted on
the windscreen or the unit itself.

I've been flying with a handheld GPS for almost ten years an have only
lost signal once in flight. And that was only for less than a minute.
Since I didn't do anything to get the signal back, I don't think it had
anything to do with antenna placement.

Now, if we're talking about precision GPS approaches, that's a different
story. But enroute navigation (and possibly even non-precision GPS
approaches) should be just as safe with a handheld as a panel mount.


-m
--
## Mark T. Dame
## VP, Product Development
## MFM Software, Inc. (http://www.mfm.com/)
"If you have to ask, you won't understand."

Peter R. wrote:
"Peter R." wrote:


Yes, I am going to maintain that premise because even more unthinkable,
someone was actually killed flying a GPS approach with nothing but a VFR
GPS.


Here's the accident report:

http://www.ntsb.gov/ntsb/brief.asp?e...23X05372&key=1

According to the accident report the plane impacted a tower just left of
the centerline but 450 below the published minimum height. Short of
WAAS no GPS will keep you from trouble if you don't follow the altitude
restrictions on the plate. I find it interesting that the report
mentions that a GPS was found in the plane but makes no mention of
charts on board. Could this have been a case of him not having the
plate but trying to fly the approach from his VFR GPS? If this is the
case the certification level of the GPS has no bearing in the crash.

Mark T. Dame wrote:


Now, if we're talking about precision GPS approaches, that's a different
story. But enroute navigation (and possibly even non-precision GPS
approaches) should be just as safe with a handheld as a panel mount.

You will usually have as good of accuracy with a hand-held (with an
external antenna, but you lack the interity because you don't have
approach RAIM.

Would this ever matter?

It depends upon the volume of operations. For you personally, the
RAIM-hole day may never occur when you're using your hand-held for an
RNAV IAP.

Since there aren't any precision RNAV IAPs, other than LPV (which
requires WAAAS) I fail to see your distinction between precision and
non-precision.

John Theune wrote:

Peter R. wrote:

"Peter R." wrote:


Yes, I am going to maintain that premise because even more unthinkable,
someone was actually killed flying a GPS approach with nothing but a VFR
GPS.



Here's the accident report:

http://www.ntsb.gov/ntsb/brief.asp?e...23X05372&key=1

According to the accident report the plane impacted a tower just left of
the centerline but 450 below the published minimum height. Short of
WAAS no GPS will keep you from trouble if you don't follow the altitude
restrictions on the plate. I find it interesting that the report
mentions that a GPS was found in the plane but makes no mention of
charts on board. Could this have been a case of him not having the
plate but trying to fly the approach from his VFR GPS? If this is the
case the certification level of the GPS has no bearing in the crash.

That accident was the result of the pilot's failure to fly the correct
altitude. It had nothing to do with the type of GPS being used.

"Steven P. McNicoll" wrote in message
news

"Wizard of Draws" wrote in message
news:BF96C057.43EB4%jeffbREMOVE@REMOVEwizardofdraw s.com...

So...do I tell a briefer to note that I have a VFR GPS and will the
controllers take note, sending me direct, off airways? Will it make any
difference to them at all? Given the fact that nearly everyone has one
nowadays, will they assume I have a GPS even if I don't indicate it?


If you file off airways and if radar monitoring can be provided and if
specific routing is not required for your departure/destination airport
then you'll get direct routing. Indicating you have a VFR GPS makes no
difference.


That seems to be an overly broad statement. I have put "VFR GPS" in Remarks
when filing /U for an off-airways (random) route and had controllers
specifically refer to using my VFR GPS to proceed direct to an intersection.
Whether they should have done so is another issue. But is sure seemed to
make a difference.

John Theune wrote:

http://www.ntsb.gov/ntsb/brief.asp?e...23X05372&key=1

According to the accident report the plane impacted a tower just left of
the centerline but 450 below the published minimum height. Short of
WAAS no GPS will keep you from trouble if you don't follow the altitude
restrictions on the plate. I find it interesting that the report
mentions that a GPS was found in the plane but makes no mention of
charts on board. Could this have been a case of him not having the
plate but trying to fly the approach from his VFR GPS? If this is the
case the certification level of the GPS has no bearing in the crash.

Baro is used for height.

Ron Lee

"Peter R." wrote:

Ron Lee wrote:

You should note that if you lose lock (too few satellites) then your
display will start flashing (or portions of it). That is not RAIM
which determines if you have a signal error.

Just to clarify, are you saying that a *VFR* GPS's screen flashes when the
GPS loses the required number of satellites for position calculation and
that error is not a result of built-in RAIM?


Portions do such as position. Take your favorite handheld and look
at various displays. Note that some will flash until you get a solid
GPS lock.

Ron Lee