Compass turns revisited

The interesting question is whether an examiner would insist on setting
up a situation, however improbable, that would require the student to
do partial panel flying without the GPS.

What do you mean "improbable"? The student gets his rating in a Cirrus,
rents a 172 on vacation, it has no GPS, and it loses vacuum.

Jose
--
Get high on gasoline: fly an airplane.
for Email, make the obvious change in the address.

Michael,

I think you need to brush up on your Garmin GPS's. In the Cirrus, I
believe, the Garmins drive the Avidyne display. One of the navigation pages
on the Garmin displays a CDI that scales properly to approach sensitivity.
That is much more accurate than following the magenta line for a backup
approach.

Ron


"Michael" wrote in message Well, that's
a defeatist attitude. I would like to think that I would
come up with some method they could handle.

Just turning until the little picture of the airplane is pointing in
the same direction as the purple line might just be a reasonable plan

with today's cockpits.

In a glass cockpit Cirrus (at least the one I flew) it is the only
plan. A PFD failure leaves you with ASI, electric AI, Altimeter - and
two Garmin 430's without CDI's (the only CDI is built into the HSI
presentation on the PFD). The only approach you can shoot after PFD
failure is a GPS, and you can shoot it ONLY by turning until the little
picture of the airplane is pointing in the same direction as the purple
line. I suppose you could use a compass, but I'm not sure what the
benefit would be.

I think you need to brush up on your Garmin GPS's. In the Cirrus, I
believe, the Garmins drive the Avidyne display.

Which is the PFD. The guidance in the latest revision of the PTS calls
for a non-precision approach to be performed without the PFD if the
aircraft is capable, and this one is.

One of the navigation pages
on the Garmin displays a CDI that scales properly to approach
sensitivity.

Sure - but it still only works for the GPS, not the VOR/LOC. You're
still limited to GPS approaches only.

That is much more accurate than following the magenta line for a
backup
approach.

This is not correct for three reasons.

First, the accuracy of the data is not affected by the presentation.
It is a function of satellite geometry and the underlying algorithms.
You're talking about precision, or resolution.

Second, you can zoom the map to a view of only a few hundred feet, and
if you so choose, you can configure the 430 to auto zoom as you get
closer. Your effective precision in this case is about 25 feet, which
is better than you can do with the CDI. This is better than the 430
can consistently do. In other words, you have accessible to you a
display with a level of precision not justified by the underlying
accuracy.

And finally, using the CDI only gives you information about your
position relative to the FAC. This is inherently wrongheaded. VOR/LOC
work that way because that's all the information you have, but the GPS
also has track information. The map display presents the same position
information as the CDI, with the same accuracy and any practically
usable precision, and it also presents the track information
graphically, such that the pilot can almost immediately see whether he
is converging with the FAC, diverging from it, or paralelling it -
without having to estimate this by monitoring the movement of the CDI
over time. This will allow the pilot to more consistently track the
course.

Thus, while I will grant you that there is indeeed a plan other than
watching the little airplane and its position and direction relative to
the courseline, it's a clearly inferior plan since it will yield
inferior results while requiring all the same equipment.

Michael

What do you mean "improbable"? The student gets his rating in a Cirrus,
rents a 172 on vacation, it has no GPS, and it loses vacuum.
Jose

That's no excuse for an examiner to create his own personal PTS.

I don't know that's creating "his own personal PTS". The examiner is
supposed to show that the applicant is safe for the flying he or she is
licensed to do.

Well, yes, the resulting pilot should also have the sense to not fly
aircraft he is ill equipped to handle should failure-prone components
fail, but this can be overextended the other way to not require
licensing at all.

What is your opinion of "just learn the answers" to the written test,
and that being sufficent for the oral? IN all cases judgment is involved.

Jose
--
Get high on gasoline: fly an airplane.
for Email, make the obvious change in the address.

The applicant does not get to tell the examiner how he would like to
deviate from the standards.

Likewise, the examiner has no basis for rejecting an applicant because
he does not meet the subjective personal standards of the examiner.

Using the BFR guide as an example (it's what I have in my hand) there is
a "ground" requirement. One can deliver, by rote, the exact answers to
questions on the ground reqirement, and do so with no understanding
whatsoever of what you are saying. Should an applicant be failed for
"failing to show understanding..." if he does in fact give the right
answers? Would probing further be "coming up with your own BFR"?

There is a


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Get high on gasoline: fly an airplane.
for Email, make the obvious change in the address.

(continued...)
There is an air portion too, and although a BFR is not the same as
getting a new rating, the principle is the same. One must =safely=
demonstrate flying more or less within those standards for a successful
BFR. (I say "more or less" because the BFR book I have specifies that
the standards are not mandatory). I would posit that the examiner =is=
(subject to review by another examiner if there is a dispute) not only
empowered, but required to make sure that the applicant has the
requisite (muscular) understanding, and isn't "flying by rote".

Jose
--
Get high on gasoline: fly an airplane.
for Email, make the obvious change in the address.

If you grounded everybody who flies by rote, he skies would grow
strangely silent.

I meant "that can fly =only= by rote".

Butr thanks for the chuckle. (What is "muscular understanding", by
the way?)

"muscular understanding" is my (coined) analog opposed to rote
mecahnics. It is important to fly (and understand flying) in such a way
that when circumstances turn less than ideal, they don't turn
disastrous. Granted we train for this so that the proper responses come
by rote in a way, but it is important to have these responses in reserve.

Jose
--
Get high on gasoline: fly an airplane.
for Email, make the obvious change in the address.

"Michael" wrote in message
oups.com...
Some students just don't get math. For them, the mental math required
to figure out how many seconds the turn needs to be is too much to do
while flying under the hood. For others, the jumping around, lead, and
lag of the compass is too difficult to deal with - they prefer to time
the turn, the check the compass only in level flight.

For some reason, despite two 'A' levels in maths, I have brain failure with
my three times table when trying to figure out timed turns. So long as I
take a few seconds to double-check your multiplication, though, and I sanity
check it (e.g. if you're turning 120 degrees it should take less than a
minute, not more) it's not a problem.

I personally belong to the latter camp. I am a strong believer in only
looking at the compass when I know it will be accurate, and using time
for turns when the heading gyro is not available.

Seconded. The two aircraft I spent most of my learning hours in had
compasses that were pretty grim (mainly around North and South, of course)
unless you were flying absolutely straight, which made even checking the DI
a bit of a chore. There wasn't really an alternative to a timed turn if you
wanted to end up pointing even vaguely the right way.

D.

wrote:
On 4 Apr 2005 13:05:12 -0700, "paul kgyy" wrote:

The examiner was not authorized to do this.

Would you give a CFR reference for me on this?

Thanks,

T.

"David Cartwright" wrote in message ...
"Michael" wrote in message
oups.com...
Some students just don't get math. For them, the mental math required
to figure out how many seconds the turn needs to be is too much to do
while flying under the hood. For others, the jumping around, lead, and
lag of the compass is too difficult to deal with - they prefer to time
the turn, the check the compass only in level flight.

For some reason, despite two 'A' levels in maths, I have brain failure with my three times table when trying
to figure out timed turns. So long as I take a few seconds to double-check your multiplication, though, and I
sanity check it (e.g. if you're turning 120 degrees it should take less than a minute, not more) it's not a
problem.


I think its easier just to do it on the dg (or even an obs if your dg has failed and is covered up)-- as
Gardner said, count 10 seconds per "numbered" heading, even if it means putting your finger physically on the
numbers as you count from your current heading to your desired heading...

Cheers,
John Clonts
Temple, Texas
N7NZ