FMS Missing Inbound Course on Intercept

[Icarus747]

Heelo:

Doing the following exercise:

Out of JFK 13 L, Turn right heading 270, intercept J42 to RBV.

Simple enough.  On the RTE page you enter J42 in 1L and RBV in R1R.  LAURN auto populates into 1R and knocks RBV down to 2R.  This is all correct.

On the 270 heading you should intercept J42 INSIDE LAURN.  So to make sure VNAV turns toward RBV, and not LAURN, RBV should be put in L1 on the legs page.  (Not doing this step may result in a turn to RBV, a turn to LAURN, or flying straight through the course!)  The course for J42 SHOULD AUTO-POPULATE in 6R.  It doesn't.  It will in our airplanes and simulator.  Thoughts?

[emerydc8]

Doesn't Charlie still hand you that laminated 8" x 11" sectional chart that no one can read? Ha!
I agree, the inbound course should populate in 6R. You are right -- our sims do it. Is it possible that this is a database issue?

Jon

[United744]

I get the ABEAM PTS but no option to enter an intercept course.

I can only enter an intercept course if I do a direct to the current way point. I enter an intercept course at R6, but it doesn't stick and the intercept course above the way point remains as dashes.

Something is seriously wrong. I get completely inconsistent results and can even bug out the FMS.

On the LEGS page after dealing with the RTE page:

* L3 to L1
* Accept ABEAM PTS
* L1 to L1
* Enter intercept course 270
* EXEC

I get inconsistent and sometimes broken results.

Problems:

ABEAM PTS displaying incorrectly (bugged-out lines)
ABEAM PTS in the wrong place
Random intercept course that is anything except as entered

[Hardy Heinlin]

Hello Icarus747,

in the current PSX version the INTC CRS at 6R is boxed when there is no waypoint after the direct-to waypoint; in your scenario there is no waypoint after RBV probably? I now understand that the boxes are not necessary in such a scenario as the direct leg (to RBV) has a defined course from the preceding waypoint, and that's all the FMC needs to suggest a INTC CRS in small font. I'll try to modify this in the next PSX update.

For now you can solve this problem by manually entering 232 at 6R. 232 is the course from LAURN to RBV.
Or just enter a waypoint after RBV before you make a direct to RBV.


|-|ardy


United744, what are you doing? Where's your aircraft? What's your route?

[United744]

The aircraft is located on JFK RW22L.

The route was entered as described above, with KJFK for both departure and arrival.

I enter the airway and way point as described above, then attempt to enter the intercept course.

As described, I get inconsistent results. How is that even possible? Do the same thing the same way twice, get a different outcome?

[Hardy Heinlin]

Situ file?

[United744]

I'll provide one tomorrow.

[Hardy Heinlin]

Wait. Situ file not required.

ABEAM PTS key should not appear on the ground. Don't use that on the ground. I'll remove the ABEAM PTS key for on-ground conditions in the next update.

[Hardy Heinlin]

Icarus747,

when you tried your direct-to RBV scenario in the big sim, was there any leg after RBV?

In PSX, the direct-to field at 6R is boxed whenever there is no leg after the direct-to fix. This is the case when there is a route discontinuity or the end of the route after the direct-to fix. This is just a cosmetic feature. The FMC knows the course, it just won't show it.

I can't remember where I got this information from that the boxes appear when there's no leg after the direct-to fix.

Anyway, there must be a condition in the real FMC that causes the boxes to appear. If I remove the above conditions, the boxes will never appear. That can't be correct either.


Regards,

|-|ardy

[emerydc8]

I can't remember where I got this information from that the boxes appear when there's no leg after the direct-to fix.

When I did the NAT reversal video using PSX I noticed that when I was building the return route by inserting the last waypoint I passed in 2R and then next to last in 3R, I always had to insert that next to last waypoint in 3R and bring 2R down to the s/p and up to 1R in order to get the return course (the return course between the original track and the last waypoint I passed) to generate in 6R. This is how Atlas teaches it (insert the previous two waypoints going back), but I'm not sure if that's the reason they do it, or whether they just wanted to get two waypoints in the box to give you more time to deal with the problem while headed back. This could be different than when you have a published airway in the database like the original poster's situ.

[Hardy Heinlin]

In PSX update 10.36 there will be this rule:

If the empty leg after the direct-to fix is a route discontinuity (i.e. if an ensuing leg exists), the boxes will be shown.

If the empty leg after the direct-to fix is the end of the route, the boxes will not be shown (instead, as usual, the last used course to that fix will be displayed in small font).


|-|

[Hardy Heinlin]

The effects discussed above should no longer occur in PSX update 10.36:

http://aerowinx.com/board/index.php?topic=4191.0


|-|ardy

[United744]

Wait. Situ file not required.

ABEAM PTS key should not appear on the ground. Don't use that on the ground. I'll remove the ABEAM PTS key for on-ground conditions in the next update.

Ahh! OK!   I'll try again with the latest update.

[Icarus747]

That was it Hardy... no fix beyond RBV in the RTE.  You're awesome!  Thanks!