7.24
Arc and Radial Intercepts
7.24. Arc and Radial Intercepts See FAA-H-8083-15B for detailed information on arc and radial intercepts. At normal T-6 airspeeds, lead points are not large, and the rate of CDI movement during the intercept can be used to determine the lead point.
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7.24.1. Objective. Intercept an arc from a radial and/or intercept a radial from an arc.
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7.24.2. Description. Maneuver aircraft to intercept an arc from a radial and/or intercept a radial from an arc.
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7.24.3. Procedure. See FAA-H-8083-15B for procedures.
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7.24.4. Techniques.
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7.24.4.1. Arc Interception from a Radial. Tune, identify and monitor the NAVAID used for the intercept and determine the direction of turn. Using aircraft calculations found in FAA-H-8083-15B, determine the lead point necessary to intercept the arc. When the lead point is reached, turn to place the bearing pointer on the 90° index.
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7.24.4.2. Interception from an Arc. Tune, identify and monitor the NAVAID used for the intercept and determine the direction of turn. Using aircraft calculations found in FAA- H- 8083-15, determine the lead radial necessary to intercept the desired course. When the lead point is reached, roll to the bank angle used in the lead point calculation and turn to roll out on the radial.
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7.24.5. Arc Maintenance Techniques.
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7.24.5.1. Corrections. If the aircraft is outside of the desired arc, turn to place the bearing pointer slightly above the 90° index. If inside, turn to place the bearing pointer slightly below the 90° index. (Rule of Thumb: Displace the bearing pointer 5° below the reference point for each one-half mile deviation to the inside of the arc, and 10° above the reference point for each half mile outside the arc).
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7.24.5.2. While on the arc, as the bearing pointer falls, continue to make small turns to keep it on the 90° index. Alternatively, a series of short straight legs may be flown allowing the bearing pointer to fall a few degrees below the 90° index then turning to place the bearing pointer a few degrees above the 90° index. When using this technique, the aircraft will fly slightly outside and inside the arc alternatively on each leg.
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