OBS Mode for procedure turn

When using a GPS in leg mode going to the IAF for a procedure turn, when you
switch it to OBS mode, don't you loose your navigation (except for the
moving map)? You don't want to wait too long to switch to OBS, or else it
may sequence to the next waypoint when you get to the IAF, but the sooner
you do it, the sooner your navigating with just the moving map, aren't you?

On Jun 11, 5:28 pm, "kevmor" wrote:
When using a GPS in leg mode going to the IAF for a procedure turn, when you
switch it to OBS mode, don't you loose your navigation (except for the
moving map)? You don't want to wait too long to switch to OBS, or else it
may sequence to the next waypoint when you get to the IAF, but the sooner
you do it, the sooner your navigating with just the moving map, aren't you?

Depends on which GPS you are talking about. On the GNS430, if you
select the correct IAF it should sequence you to the PT instead of
inbound.

I'm using the King KLN-94, it won't sequence to the PT...

"Andrew Sarangan" wrote in message
oups.com...
On Jun 11, 5:28 pm, "kevmor" wrote:
When using a GPS in leg mode going to the IAF for a procedure turn, when
you
switch it to OBS mode, don't you loose your navigation (except for the
moving map)? You don't want to wait too long to switch to OBS, or else
it
may sequence to the next waypoint when you get to the IAF, but the sooner
you do it, the sooner your navigating with just the moving map, aren't
you?

Depends on which GPS you are talking about. On the GNS430, if you
select the correct IAF it should sequence you to the PT instead of
inbound.

If you select the OBS mode prior to reaching your intersection, it wont
sequence to the next waypoint. (you know this..)

Fly your procedure turn/Hold (whichever entry, or the 180 turn to
outbound).. when you turn inbound, the device should still give you
navigation back to the selected waypoint (no worse than doing a PT or
hold with a VOR/Nav)

You should be flying by reference to the NAV/HSI indicator, not the
moving map. The HSI/Nav needles still work even when waypoint sequencing
is suspended during (OBS) PT/Hold maneuvers.

Have you ever done a hold or PT with a VOR type instrument? (no GPS
involved whatsoever) That might be beneficial for wrapping yourself
around this conceptually...

Dave



kevmor wrote:
I'm using the King KLN-94, it won't sequence to the PT...

"Andrew Sarangan" wrote in message
oups.com...

On Jun 11, 5:28 pm, "kevmor" wrote:

When using a GPS in leg mode going to the IAF for a procedure turn,
when you
switch it to OBS mode, don't you loose your navigation (except for the
moving map)? You don't want to wait too long to switch to OBS, or
else it
may sequence to the next waypoint when you get to the IAF, but the
sooner
you do it, the sooner your navigating with just the moving map,
aren't you?


Depends on which GPS you are talking about. On the GNS430, if you
select the correct IAF it should sequence you to the PT instead of
inbound.

kevmor wrote:
When using a GPS in leg mode going to the IAF for a procedure turn, when
you switch it to OBS mode, don't you loose your navigation (except for
the moving map)? You don't want to wait too long to switch to OBS, or
else it may sequence to the next waypoint when you get to the IAF, but
the sooner you do it, the sooner your navigating with just the moving
map, aren't you?

If you have a C146a navigator you don't have to do any of this switching
nonsense.

Ok, I think I've got it... As I'm approaching the fix, I hit OBS, and since
I had the correct OBS setting, I'm navigating to it still just as if it were
a VOR. (Before I was thinking of pressing OBS and setting the inbound
course immediately, where the CDI goes to the side and your still trying to
go to the fix).

"Dave S" wrote in message
ink.net...
If you select the OBS mode prior to reaching your intersection, it wont
sequence to the next waypoint. (you know this..)

Fly your procedure turn/Hold (whichever entry, or the 180 turn to
outbound).. when you turn inbound, the device should still give you
navigation back to the selected waypoint (no worse than doing a PT or hold
with a VOR/Nav)

You should be flying by reference to the NAV/HSI indicator, not the moving
map. The HSI/Nav needles still work even when waypoint sequencing is
suspended during (OBS) PT/Hold maneuvers.

Have you ever done a hold or PT with a VOR type instrument? (no GPS
involved whatsoever) That might be beneficial for wrapping yourself around
this conceptually...

Dave



kevmor wrote:
I'm using the King KLN-94, it won't sequence to the PT...

"Andrew Sarangan" wrote in message
oups.com...

On Jun 11, 5:28 pm, "kevmor" wrote:

When using a GPS in leg mode going to the IAF for a procedure turn,
when you
switch it to OBS mode, don't you loose your navigation (except for the
moving map)? You don't want to wait too long to switch to OBS, or else
it
may sequence to the next waypoint when you get to the IAF, but the
sooner
you do it, the sooner your navigating with just the moving map, aren't
you?


Depends on which GPS you are talking about. On the GNS430, if you
select the correct IAF it should sequence you to the PT instead of
inbound.

kevmor wrote:
Ok, I think I've got it... As I'm approaching the fix, I hit OBS, and
since I had the correct OBS setting, I'm navigating to it still just as
if it were a VOR. (Before I was thinking of pressing OBS and setting
the inbound course immediately, where the CDI goes to the side and your
still trying to go to the fix).

Sounds about right.

You should get the waypoint light flashing as you fly over/fly by. When
you get that waypoint passage indication, fly your PT or Hold. If you
have a to/from indication on your CDI that should flip/change as well
when you pass the station/waypoint

When you turn inbound, make whatever adjustments you need to, with your
plane and with the Obs (usually only a degree or two if you nail the
pt/hold) to fly TO the waypoint. If you are ready to continue the
approach, un-select OBS and when you fly over, you sequence to the next
point as expected.

This particular issue is addressed in the KLN-94 Pilot's Guide section
5.5, or page 145 - 150 if you have it in PDF.

Hope its clearing up a bit
Dave