CONSTANT ANGLE OF BANK TURNS (CABT)
All considerations for turning flight in the Instrument Stage are the same as in Contact
Establish an AOB on the attitude gyro and maintain that AOB throughout the turn.
Crosscheck the nose position with the altimeter and VSI. Corrections to maintain altitude are
made in the same manner as in straight and level flight.
To prevent turning beyond the desired heading, it is necessary to anticipate or lead the new
heading. A reasonably accurate rule of thumb is to lead this new heading by the number of
degrees equal to onethird the AOB used in making the turn. If, for example, the AOB is 30º,
the rollout should be started 10º before reaching the desired heading.
In the example above, when you pass 10º prior to your specified heading, shift your scan
completely to the attitude gyro and roll out on the gyro. This rule will be used during all turns to
Overrotating the nose as the AOB is established, resulting in a climb. All pilots have
a tendency to pull back stick while rolling into a turn.
Looking away from the attitude gyro before the AOB is set, resulting in overbanking
as the wings continue to roll.
Failure to maintain a level flight scan as the turn progresses, allowing the nose to fall,
resulting in a loss of altitude.
Failure to roll out on the desired heading due to slow or improper scan (not looking at
the RMI for turn performance and not applying the "onethird rule").
Not rolling out on the gyro. The most common error is to watch the RMI during
rollout. Thus, the wings do not level and the nose is raised or lowered.
Rolling too fast. This prevents proper coordination between nose and wing attitudes.
RATE TURNS (RT)
During normal IFR flight along airways, all turns will generally be done at a specified rate, either
standard or onehalf standardrate turns. The standardrate of turn is 3º per second. At 3º per
second, a turn of 180º will take one minute and a 360º turn will take two minutes. The figure on the
next page is a chart showing the AOB necessary to produce a 3º per second turn at various airspeeds
and altitudes. From the chart, you can see that an aircraft operating at high speeds requires a steep
AOB to produce a 3º per second turn. Steep turns are more difficult to fly than shallow turns, since
they result in heavy load factors; for example, a 60º bank turn applies a two "G" force to the aircraft
3-12 BASIC INSTRUMENTS FLIGHT PROCEDURES