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