Basic Instrument Maneuvers
Instrument Flight
1/2 STANDARD RATE TURNS
A 1/2 standard rate turn (1/2 SRT) is performed at 1-1/2 degrees per second. Therefore, a heading
change of 30 degrees will take 20 seconds to complete. To accomplish this rate at different airspeeds,
you will have to vary the bank angle. A good rule of thumb for determining bank angle between 15,000
and 20,000 ft is to use approximately 10 percent of indicated airspeed. At higher altitudes, you will need
more bank than 10 percent of indicated airspeed, while at lower altitudes you will need less bank than 10
percent of indicated airspeed to maintain a 1/2 SRT. For example, at 250 KIAS and 18,000 ft, the bank
angle would be approximately 25 degrees. Establishing and maintaining a 1/2 standard rate turn at any
altitude requires that you monitor the turn needle and adjust the bank angle as necessary to achieve one
needle-width of deflection.
TIMED TURNS, 1/2 STANDARD RATE
For practice, you should start your 1/2 SRTs from a cardinal heading using a lead point of 3 seconds prior
to the clock’s second hand passing the 6 or 12 position. Roll into the turn on the ADI (approximately 25
degrees of bank at an airspeed of 250 KIAS) and adjust the pitch attitude to maintain level flight. Initially,
scan the ADI for bank and pitch control, the VSI or altimeter for pitch, and the airspeed indicator for
speed.
Once you have made the necessary pitch and power changes, check the turn needle and adjust the bank
as necessary to maintain 1 needle-width of deflection. When the ADI shows 30 degrees of heading
change, check that 20 seconds have elapsed on the clock. Always check the time when you reach the
correct number of degrees of turn (not vice versa) to ensure that you are keeping your scan on the flight
instruments rather than on the clock.
Continue to check the clock at least every 30 degrees of turn and adjust (AOB) rate of turn accordingly. If
you are ahead of the clock, decrease AOB; if you are behind the clock, increase AOB. When you have
the turn back on time, readjust your bank angle to a 1/2 SRT. Use no more than 30 or fewer than 10
degrees of bank when making your corrections.
Lead your roll-out by one-third of the angle of bank, simultaneously reducing power to the level flight
setting if it has been advanced.
Bank angle: Approximately 10 percent of IAS (25 degrees at 250 KIAS)
Rate: 1-1/2 degrees per second
Throttle: As required to maintain airspeed
Pitch: As required to maintain level flight
Lead point for roll-out: 1/3 of the AOB
(12-00) Original
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