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AIM

10/12/17

1−2−3

Performance−Based Navigation (PBN) and Area Navigation (RNAV)

FIG 1−2−4

Direct to Fix Leg Type

(3) Course to Fix. A Course to Fix (CF)

leg is a path that terminates at a fix with a specified

course at that fix. Narrative: “on course 150 to

ALPHA WP.” See FIG 1−2−5.

FIG 1−2−5

Course to Fix Leg Type

(4) Radius to Fix. A Radius to Fix (RF)

leg is defined as a constant radius circular path around

a defined turn center that terminates at a fix. See

FIG 1−2−6.

FIG 1−2−6

Radius to Fix Leg Type

(5) Heading. A Heading leg may be

defined as, but not limited to, a Heading to Altitude

(VA), Heading to DME range (VD), and Heading to

Manual Termination, i.e., Vector (VM). Narra-

tive: climb heading 350 to 1500”, “heading 265, at

9 DME west of PXR VORTAC, right turn heading

360”, “fly heading 090, expect radar vectors to

DRYHT INT.”

(c) Navigation Issues. Pilots should be

aware of their navigation system inputs, alerts, and

annunciations in order to make better−informed

decisions. In addition, the availability and suitability

of particular sensors/systems should be considered.

(1) GPS/WAAS. Operators using TSO−

C129(), TSO−C196(), TSO−C145() or TSO−C146()

systems should ensure departure and arrival airports

are entered to ensure proper RAIM availability and

CDI sensitivity.

(2) DME/DME. Operators should be

aware that DME/DME position updating is depen-

dent on navigation system logic and DME facility

proximity, availability, geometry, and signal mask-

ing.

(3) VOR/DME. Unique VOR character-

istics may result in less accurate values from

VOR/DME position updating than from GPS or

DME/DME position updating.

(4) Inertial Navigation. Inertial reference

units and inertial navigation systems are often

coupled with other types of navigation inputs,

e.g., DME/DME or GPS, to improve overall

navigation system performance.