CHAPTER THREE CHG 2
Rate and Timed Turns
Because of the errors in the magnetic compass, it is more feasible to make timed turns
(at StandardRate or OneHalf StandardRate) rather than to attempt to turn on the
magnetic compass. Coordination with aileron and rudder is needed rolling in and out
of turns to counteract adverse yaw which produces a delay in turn indications on the
turn needle. Under actual partial panel instrument conditions, it is desirable that
partial panel timed turns do not exceed OneHalf StandardRate. A StandardRate
Turn is not recommended because of the high AOB and extreme control pressures
necessary, which could cause the turn to become uncontrollable and place the aircraft
in an unusual attitude.
Timed turns for heading changes of 30º or more will be done at OneHalf Standard
Rate. Compute the time to turn in seconds by multiplying the number of degrees to
turn by ⅔. Turn using a oneneedle width deflection. For turns of 29º of less, turn at
⅔needle width deflection for a number of seconds equal to the number of degrees to
turn. The attitude control instruments for a level timed turn are the same as for
straight and level.
When rolling into a timed turn, start when the second hand of the clock is at the 3, 6,
9, or 12 positions. Do not use any lead when rolling in or rolling out of the turn.
Begin the roll into the turn when you commence timing and start your rollout at the
completion of your timing. Attempt to roll in and out of the turn at a constant rate.
Since errors may result from improper timing or use of the turn needle, corrections to
heading may be necessary upon completion of the turn. If, after the completion of the
first turn, the error is 30º or greater, correct to heading using a oneneedle width turn,
as above. For errors of 29º or less, use the above procedures for a ⅔needle width
The turn needle tends to lag slightly behind wing movement, because of the inertia of
the needle itself. Thus, rate of roll must be smooth and slower than when in full panel
to decrease the lag as much as possible. This lag necessitates the need to "lead" the
needle. In other words, as the turn needle approaches a needle width deflection (say
eighttenths deflection), stop the wing movement with stick pressure. The needle
will continue to deflect to approximately a full needle width. The same holds true
when rolling back to wings level.
The nose attitude control fundamentals discussed for straight and level flight, partial
panel, are applicable here, as these are level turns.
Magnetic Compass after turn and wings
BASIC INSTRUMENTS FLIGHT PROCEDURES 3-41