by Jonathan M. Stern
As in straight and level flight, the altimeter is the primary pitch instrument in a level turn. In a standard rate turn, the pilot maintains a 3° per second turn. Therefore, the turn coordinator becomes the primary bank instrument and should take the place of the heading indicator in the scan pattern described previously. (See Figure 12.4.)Figure 12.4. The turn coordinator is the primary bank instrument in a standard rate turn.
Should the pilot choose to make a 30° banked turn instead of a standard rate turn, the attitude indicator becomes the primary bank instrument. This is the only situation in which the attitude indicator is a primary performance instrument. The scan pattern for a standard rate, right turn appears in Table 12.3.
|TABLE 12.3 Scan Pattern for a Standard Rate Right Turn
|Shows approximately 20° right bank and slight pitch up (the bank angle necessary for a standard rate turn can be estimated using the following formula: bank angle = airspeed in knots / 10 + 7
|At desired altitude.
|Same appearance as last scan.
|Shows standard rate right turn.
|Same as last scan.
|At desired cruise speed.
|Same as last scan.
|Am I approaching my desired heading?
As a rule of thumb, the roll out of the turn should begin when the airplane is within one-half of the bank angle of the desired heading. If a 20° bank is used in the turn, and the desired heading is 260°, roll out should begin when passing through a heading of 250 degrees.
Practice making turns to predetermined headings while maintaining 5,000 feet. Practice both left and right turns. As a general rule for flying on instruments, never use a turn steeper than standard rate or a bank angle greater than one-half of the number of degrees to turn, whichever is less. In the Lear, a maximum bank angle of 30° is used while flying on instruments. When you feel comfortable with both left and right turns, pause and continue reading.