RNAV vectors

"Steven P. McNicoll" wrote in message
.net...

"Stan Prevost" wrote in message
...

From the P/CG:

==================

FINAL APPROACH COURSE- A bearing/radial/track of an instrument approach
leading to a runway or an extended runway centerline all without regard
to
distance.

COURSE-

a. The intended direction of flight in the horizontal plane measured in
degrees from north.

b. The ILS localizer signal pattern usually specified as the front course
or the back course.

c. The intended track along a straight, curved, or segmented MLS path.

==================

Final Approach Course is not the same as Final Approach Segment.


You've missed the point.

Let's look at a couple of approaches at Titletown to illustrate. First,
the ILS RWY 36:

http://map.aeroplanner.com/plates/Fa.../00873IL36.PDF

An aircraft is inbound from O'Hare, on initial contact it's instructed to
turn ten degrees left and join the runway 36 localizer. It intercepts
about thirty miles from the field and tracks inbound. No problem.

Now look at the RNAV RWY 36 approach:

http://map.aeroplanner.com/plates/Fa...s/00873R36.PDF

Same situation, an aircraft is inbound from O'Hare, on initial contact
it's instructed to turn ten degrees left and join the final approach
course for the RNAV RWY 36. It crosses the extended final about thirty
miles south of the field and continues on it's heading. There's nothing
for it to intercept, nothing similar to a localizer that it can join.


Of course there is something to intercept. There is the final approach
course. By definition, it extends southward from the runway on a course of
182 degrees forever, to SENNA and beyond.

RNAV/GPS equipment does not need a navaid signal overlying the FAC to allow
me to navigate it. I can intercept and track that FAC with my GNS430 GPS,
and it will even draw a magenta line for me on the map.

However, I don't see any advantage to such vectors over a clearance direct
SENNA. And if the MVA is higher than 2500, there can be a disadvantage.