Flight Training Instruction - Cnatra - U.S. Navy

CHAPTER FIVE T-6B PRIMARY INSTRUMENT NAVIGATION
b. When the HSI is 30º past the cardinal heading, check for 20 seconds elapsed time on
the clock. The next checkpoint is 60º of turn and the clock for 40 seconds of elapsed
time. There are two valid reasons for checking the heading change against the clock,
rather than checking the time prior to referring to the heading. The instruments are
arranged on the panel in groups. The attitude indicator, HSI, altimeter, and airspeed
indicator are grouped together. Thus, while scanning the instruments, you do not
have to shift your point of vision very far to check the HSI. Since the clock tells you
nothing about the aircraft attitude, the time spent scanning it is actually wasted. If the
clock is checked only once every 20 seconds, rather than four or five times, you will
be able to devote more time to the attitude instrument scan.
c. When checking the HSI and clock, if the turn is less than ½ SRT, increase the AOB
and check the turn needle for a greater deflection in order to catch up with the clock.
When the turn has caught up with the clock, the AOB must be readjusted to maintain
½ SRT. To roll out of the desired heading, use the one–third rule for constant AOB
turns.
d. Never use more than 20º of bank to catch up or less than 10º of bank to slow the
rate. If larger corrections are made, the rate of correction will be too rapid and cause
the heading to be bypassed. Have patience, catch up slowly and deliberately.
2. Standard Rate Turns (SRT)
a. Timed SRTs are accomplished in the same manner as ½ SRTs. Roll into the turn on
the attitude indicator, doubling the 10 percent rule and crosscheck the turn needle for
two needle width deflection, but do not exceed 30º AOB. Since the aircraft is turning
twice as fast (3º per second), it will be necessary to check the clock every 30º for ten
seconds of elapsed time. The scan pattern corrections for desired rate of turn and the
procedure for leading the rollout on the desired heading are the same as the ½ SRT.
Remember to crosscheck the nose attitude with altimeter and VSI, making power and
attitude adjustments as necessary due to the resultant decrease in vertical lift.
b. Never use more than 30º of bank to catch up or less than 15º of bank to slow the
rate.
Common Errors.
1. Not using a three second lead.
2. Not relying on the wing attitude instrument (turn needle), but rather, trying to fly off of the
performance instruments. The turn needle is one of the most accurate instruments in the aircraft,
believe it. Remember, the performance checks are only read every 30º.
3. Unbalanced flight.
4. Overcorrecting AOB.
5-4 BASIC INSTRUMENT PROCEDURES