t-39 - Chief of Naval Air Training
t-39 - Chief of Naval Air Training
t-39 - Chief of Naval Air Training
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T-<strong>39</strong> FLIGHT PREPARATION STUDENT GUIDE<br />
d. Course control<br />
Theoretically, you should always roll out on the radial after leading turns; however, this<br />
is not always the case. As soon as the aircraft position can be determined after a turn, a<br />
correction should be made to the proper radial.<br />
Prior to any course change a wind-adjusted heading should be determined in order to<br />
maintain course on the next leg. Knowledge <strong>of</strong> the winds (either preflight or computed)<br />
allows a quick determination <strong>of</strong> crab; only minor heading adjustments should be needed for<br />
the leg. If the winds are unknown, observe the drift after having been on course, then<br />
return to course and adjust the heading to compensate for the drift. The CDI can be a very<br />
effective tool in managing drift.<br />
Any CDI needle deflection indicates you are <strong>of</strong>f course. Remember the needle is a "fly<br />
to" indication and deflects in the direction you must turn. A good rule <strong>of</strong> thumb is to turn<br />
10º from wind corrected heading for every mile you are <strong>of</strong>f course.<br />
NOTE: The TACAN is the primary NAVAID enroute.<br />
e. Estimated Time <strong>of</strong> Arrival<br />
The ETA to the next point is given during the two-minute prior call. To determine<br />
ETA to the next point, divide the leg distance by ground speed in miles per minute and add<br />
to the ETA <strong>of</strong> the upcoming point.<br />
NOTE: on a 90 o turn the crosswind component becomes headwind component.<br />
EXAMPLE:<br />
1. 420 kts ground speed, leg distance 84 NM.<br />
2. 84 NM / 7 NM per minute = 12 minutes.<br />
After the initial estimate you may set up "gates" to further refine the time. A gate is a<br />
distance equal to a whole number <strong>of</strong> minutes based on the current ground speed. A sixminute<br />
gate would be <strong>39</strong>.0 NM, given a <strong>39</strong>0 kts (6.5 NM/min) ground speed. Note that a<br />
six-minute gate is the ground speed in knots divided by 10 (since six minutes is a tenth <strong>of</strong><br />
an hour), and a five-minute gate is the ground speed in miles per minute multiplied by 10<br />
then divided by 2.<br />
NOTE: Use <strong>Air</strong>craft clock (time mode) for ETAs vice the flight time or elapsed time modes.<br />
f. Estimated IAF fuels<br />
Estimated fuel at the Initial Approach Fix (IAF) is given during the wings-level call and<br />
after each ground speed check. Several techniques for fuel computation may be used. Four<br />
will be explained in the following discussion and are summarized in Figure 2-1. The<br />
following examples use the information below:<br />
DISTANCE AND ETE 1<br />
1 Adjusted for preflight winds<br />
2-12