primary flight instruments on partial panel

In primary and supporting method of attitude instrument flying, which
do you consider the primary instrument for bank in the partial panel
situation (loss of both attitude indicator and heading indicator)?
Turn coordinator or magnetic compass?
thank you
Greg
greggordon.org/flying

You would use the TC or TB to control bank angle, it is the
instrument that you control, therefore primary. You monitor
the compass to fly a heading which is the desired result.
Using the compass as a control instrument generally requires
a south heading so that the compass turning error is in the
correct direction.


--
James H. Macklin
ATP,CFI,A&P

"Greg" wrote in message
ups.com...
| In primary and supporting method of attitude instrument
flying, which
| do you consider the primary instrument for bank in the
partial panel
| situation (loss of both attitude indicator and heading
indicator)?
| Turn coordinator or magnetic compass?
| thank you
| Greg
| greggordon.org/flying
|

Greg wrote:
In primary and supporting method of attitude instrument flying, which
do you consider the primary instrument for bank in the partial panel
situation (loss of both attitude indicator and heading indicator)?
Turn coordinator or magnetic compass?

The magnetic compass isn't worth **** in a turn. It should only be
used as a heading reference in straight-and-level flight.

If you've got a good ADF you can tune in an AM broadcast station and
that makes a dandy DG replacement. Pick a station that's far enough
away that azimuth to the station is approximately constant but close
enough that you get a good strong signal. Not that most planes have
ADFs these days, and the ones that do exist tend to be pretty cruddy.

With practice, you can fly a decent ILS with just a TC, ASI, and CDI.
No AI, no DG, not even a wet compass.

Roy Smith wrote:
Greg wrote:
In primary and supporting method of attitude instrument flying, which
do you consider the primary instrument for bank in the partial panel
situation (loss of both attitude indicator and heading indicator)?
Turn coordinator or magnetic compass?

The magnetic compass isn't worth **** in a turn. It should only be
used as a heading reference in straight-and-level flight.

Actually compass turns are taught of all instrument pilots. An
instrument pilot should be able to tell you what the compass will
indicate in a turn and be able to turn to exact headings using just the
compass. For most places in the U.S. the correction is +30/-30. See
page 5-25 of the FAA's "Instrument Flying Handbook"
http://www.faa.gov/library/manuals/a...-8083-15-1.pdf

"...For example, when turning from an easterly direction to north,
where the latitude is 30°, start the roll-out when the compass
reads 37° (30° plus one-half the 15° angle of bank, or
whatever amount is appropriate for your rate of roll-out).
When turning from an easterly direction to south, start the
roll-out when the magnetic compass reads 203° (180° plus
30° minus one-half the angle of bank). When making similar
turns from a westerly direction, the appropriate points at
which to begin your roll-out would be 323° for a turn to
north, and 157° for a turn to south...."


-Robert, CFII

If I had my druthers, compass turns would be eliminated from training and
timed turns used instead. The PTS does not require compass turns, but most
CFII's teach them anyway. I'll bet my life on a timed turn, but not on a
compass turn.

Whenever this question arises I postulate this scenario: It is a dark and
stormy night, ice is beginning to become apparent, the wife's knuckles are
white and the kids are crying. The heading indicator craps out and the mag
compass looks like a washing machine. What a fine time to be determining
leads and lags and remembering rules.

Bob Gardner
"Robert M. Gary" wrote in message
ups.com...

Roy Smith wrote:
Greg wrote:
In primary and supporting method of attitude instrument flying, which
do you consider the primary instrument for bank in the partial panel
situation (loss of both attitude indicator and heading indicator)?
Turn coordinator or magnetic compass?

The magnetic compass isn't worth **** in a turn. It should only be
used as a heading reference in straight-and-level flight.

Actually compass turns are taught of all instrument pilots. An
instrument pilot should be able to tell you what the compass will
indicate in a turn and be able to turn to exact headings using just the
compass. For most places in the U.S. the correction is +30/-30. See
page 5-25 of the FAA's "Instrument Flying Handbook"
http://www.faa.gov/library/manuals/a...-8083-15-1.pdf

"...For example, when turning from an easterly direction to north,
where the latitude is 30°, start the roll-out when the compass
reads 37° (30° plus one-half the 15° angle of bank, or
whatever amount is appropriate for your rate of roll-out).
When turning from an easterly direction to south, start the
roll-out when the magnetic compass reads 203° (180° plus
30° minus one-half the angle of bank). When making similar
turns from a westerly direction, the appropriate points at
which to begin your roll-out would be 323° for a turn to
north, and 157° for a turn to south...."


-Robert, CFII

Bob Gardner wrote:
If I had my druthers, compass turns would be eliminated from training and
timed turns used instead. The PTS does not require compass turns, but most
CFII's teach them anyway. I'll bet my life on a timed turn, but not on a
compass turn.

Funny, I think compass turns are much easier under stressful
situations. Having to start and stop the clock and compute the time
necessary for the turn while holding an exact standard rate turn would
be hard. Of course, in most situations, turning within 1degree is not
required.

-Robert

Funny, I think compass turns are much easier under stressful
situations. Having to start and stop the clock

I disagree. A quick calculation tells me where the second hand should
be when I'm done. I roll out, then make little corrections as needed.

Jose
--
The monkey turns the crank and thinks he's making the music.
for Email, make the obvious change in the address.

If you're down to just the compass, worry more about keeping
the wings "level" and less about heading. The compass, in
the northern hemisphere will work as the sole instrument
only when flying south [saw between 150-210] heading. It
will be very sensitive and indicate the correct turn
direction.

If you fly very much IMC, spend the money for Sporty's
battery powered AI. And keep the needle/ball-TC too.


--
James H. Macklin
ATP,CFI,A&P


"Jose" wrote in message
m...
| Funny, I think compass turns are much easier under
stressful
| situations. Having to start and stop the clock
|
| I disagree. A quick calculation tells me where the second
hand should
| be when I'm done. I roll out, then make little
corrections as needed.
|
| Jose
| --
| The monkey turns the crank and thinks he's making the
music.
| for Email, make the obvious change in the address.

I don't like purely timed turns because I rarely get them to work
accurately. It takes time to bank into the turn and bank out and any
inaccuracies in holding a standard rate turn you can be off by 20 or 30
degrees. Using compass turns, even if don't compensate for banking
errors you will only be off by 30 degrees. What I teach is to make
large turns using the compass turns (with or without banking errors),
and then make fine adjustments. In a sense this is a combination of
compass turns and timed turns, except you don't start and stop a clock.
You time the fine adjustments in your head.



Bob Gardner wrote:
If I had my druthers, compass turns would be eliminated from training and
timed turns used instead. The PTS does not require compass turns, but most
CFII's teach them anyway. I'll bet my life on a timed turn, but not on a
compass turn.

Whenever this question arises I postulate this scenario: It is a dark and
stormy night, ice is beginning to become apparent, the wife's knuckles are
white and the kids are crying. The heading indicator craps out and the mag
compass looks like a washing machine. What a fine time to be determining
leads and lags and remembering rules.

Bob Gardner
"Robert M. Gary" wrote in message
ups.com...

Roy Smith wrote:
Greg wrote:
In primary and supporting method of attitude instrument flying, which
do you consider the primary instrument for bank in the partial panel
situation (loss of both attitude indicator and heading indicator)?
Turn coordinator or magnetic compass?

The magnetic compass isn't worth **** in a turn. It should only be
used as a heading reference in straight-and-level flight.

Actually compass turns are taught of all instrument pilots. An
instrument pilot should be able to tell you what the compass will
indicate in a turn and be able to turn to exact headings using just the
compass. For most places in the U.S. the correction is +30/-30. See
page 5-25 of the FAA's "Instrument Flying Handbook"
http://www.faa.gov/library/manuals/a...-8083-15-1.pdf

"...For example, when turning from an easterly direction to north,
where the latitude is 30°, start the roll-out when the compass
reads 37° (30° plus one-half the 15° angle of bank, or
whatever amount is appropriate for your rate of roll-out).
When turning from an easterly direction to south, start the
roll-out when the magnetic compass reads 203° (180° plus
30° minus one-half the angle of bank). When making similar
turns from a westerly direction, the appropriate points at
which to begin your roll-out would be 323° for a turn to
north, and 157° for a turn to south...."


-Robert, CFII

Jim Macklin wrote:
If you're down to just the compass, worry more about keeping
the wings "level" and less about heading. The compass, in
the northern hemisphere will work as the sole instrument
only when flying south [saw between 150-210] heading. It
will be very sensitive and indicate the correct turn
direction.

I'm not sure I follow. During my CFII training I got a solid 2 hours of
flying partial panel with compass turns. I was able to fly exact
vectors to ILS, etc. If I was off even by 2 degrees when I rolled out
on a heading my CFII would yell at me. I can tell you from experience
you 100% can fly very, very exact headings in any direction using
compass turns if you know how to read the compass and account for the
effects. I'm not saying doing so in IMC would be as easy as it is under
the hood but personally, I would do that in a second before trying to
do the math required of timed turns while under the pressure of partial
panel IMC. Of course most of us have GPSs which are actually a much
better partial panel way to figuring heading (approximated as course).

-Robert, CFII