Proceed southeast on J24:
Maintain the outbound radial (124).
2. Tune and Identify. One to two minutes prior to the intersection or fix, tune and identify the
new station (ROD, Channel 122).
3. Set the new course in the course selector window of the course indicator (055). Note the
appropriate indication in the TO-FROM indicator (TO).
4. Lead the turn. Lead the turn into the intersection to adhere as closely as possible to the
airway being flown.
Intercept and track the new radial.
During TACAN arcing, the aircraft heading should be controlled so that the TACAN needle will
remain on or near the 90° benchmark, and the DME at the desired range. The number and extent
of heading changes will vary with distance from the station and wind conditions. As a general
rule, if the aircraft is allowed to drift inside or outside the arc, a correction of about 5° of heading
per 1/2NM error should be applied (for example, if the aircraft is 1 NM outside of the arc the
nose of the aircraft should be pointed 10 degrees toward the station, (i.e. head of the TACAN
needle should be 10° ahead of the 90° benchmark). In Radio Instrument events in the 2F101, the
student will provide headings to navigate throughout each arc. In the T-2C, once established on
an arc, the IP may be asked to "maintain the arc".
A Groundspeed Check can be conducted while maintaining a course, which is oriented generally
to or from a TACAN Station. However, for best accuracy, Groundspeed Checks should be
performed only when tracking on a radial and the DME exceeds the aircraft altitude above the
TACAN divided by 1000. For example, if the aircraft is at FL210 over a TACAN, which is at an
elevation of 1000 MSL, groundspeed checks should be performed when beyond 20 DME.
"Thirty-six second" groundspeed checks conducted with digital DME can be fairly accurate.
However, at jet speeds, especially using the odometer-style DME in a T-2C, 36-second checks
are of questionable value. A, one minute, check is considered the shortest for acceptable
accuracy. Three and six minute checks are proportionately more accurate. As learned during the
primary and intermediate phases of training, groundspeed will be computed by dividing the
distance flown by the elapsed time in minutes and then multiplying by 60:
GROUNDSPEED = Distance Flown / Elapsed time in minutes
Begin timing. Punch the clock when the range indicator shows a whole number and time for at
least one minute.