I took the question to be either/or. What ever instrument
you are intending to keep at a constant, whether heading,
altitude or airspeed or RC, is your primary, but control
often is not done using that instrument.
If the choice was you have only one instrument that shows
any heading related indication, which would be primary
[compass or TC] then the compass must be primary, but the TC
would be "primary for control" and would get the scan
priority between what ever pitch instruments, the compass
might be scanned only 2% of the time with a majority of the
time on the TC/altimeter and a/s.

I further said that is all you had was the compass, then a
south heading would be best because it eliminates the
backwards turning error and magnifies the beginning of a
turn and in the correct direction...


"Robert M. Gary" wrote in message
ups.com...
|
| Jim Macklin wrote:
| I'm speaking of the question by the OP, which seemed to
be
| asking if all you had was the compass or the TC
[needle],
| which would be primary.
|
| In straigtht and level flight under partial panel the
compass would
| have to be primary because the TC cannot tell you if you
are still on
| the correct heading. Corrections would be made with the TC
though. Just
| like full panel when your DG is primary in straight
flight. It is very
| possible to roll out to a heading within 2 degrees in any
direction
| using "compass turns" technique.
|
| -Robert, CFII
|