Rate and Timed Turns

T-34C INSTRUMENTS

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 30 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 29 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 30 or greater, correct to heading using a oneneedle width turn,

as above. For errors of 29 or less, use the above procedures for a ⅔needle width

turn.

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.

Scan

Wing Attitude

Turn needle/ball

Nose Attitude

ALT/VSI

Performance

Clock

Additional

Magnetic Compass after turn and wings

level

BASIC INSTRUMENTS FLIGHT PROCEDURES 3-41