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AIM

10/12/17

5−3−23

En Route Procedures

cannot be determined, start timing when turn to

outbound is completed.

5. Distance Measuring Equipment (DME)/

GPS Along−Track Distance (ATD). DME/GPS

holding is subject to the same entry and holding

procedures except that distances (nautical miles) are

used in lieu of time values. The outbound course of

the DME/GPS holding pattern is called the outbound

leg of the pattern. The controller or the instrument

approach procedure chart will specify the length of

the outbound leg. The end of the outbound leg is

determined by the DME or ATD readout. The holding

fix on conventional procedures, or controller defined

holding based on a conventional navigation aid with

DME, is a specified course or radial and distances are

from the DME station for both the inbound and

outbound ends of the holding pattern. When flying

published GPS overlay or stand alone procedures

with distance specified, the holding fix will be a

waypoint in the database and the end of the outbound

leg will be determined by the ATD. Some GPS

overlay and early stand alone procedures may have

timing specified. (See FIG 5−3−5, FIG 5−3−6 and

FIG 5−3−7.) See Paragraph 1−1−17, Global Position-

ing System (GPS), for requirements and restriction

on using GPS for IFR operations.

FIG 5−3−5

Inbound Toward NAVAID

NOTE−

When the inbound course is toward the NAVAID, the fix distance is 10 NM, and the leg length is 5 NM, then the end of the

outbound leg will be reached when the DME reads 15 NM.

FIG 5−3−6

Inbound Leg Away from NAVAID

NOTE−

When the inbound course is away from the NAVAID and the fix distance is 28 NM, and the leg length is 8 NM, then the end

of the outbound leg will be reached when the DME reads 20 NM.

9/13/18

AIM