CDU intercepts ...

[eudoniga]

Hello folks,

anyone out there who has done experiments about the

DIR INTC / intercept leg to

features of the PM CDU, coupled with the GC for the related graphical effects ?

Thanks !

[JWS]

Ah .. don't know exactly what you mean, but i.m.h.o. the direct intercept doesn't perform like it should be in reality. I base my findings on some tests I performed last year and the FMC User's Guide by Bill Bulfer (which by the way is recommended by PM and I second that).

There it's mentioned (page 122) that after selecting the intercept course and executing ("making it big") and rolling out on the intercept heading, engaging LNAV should result in a dotted magenta line from the a/c symbol towards an unseen created waypoint on the the intercept leg (or intercept course). Now I've tried this technique but never saw a dotted line and the a/c didn't follow the dotted heading up to the unseen point but started a slow curve immediately towards the next waypoint.

With all the problems we've had lately with changing routes and so on, you can understand that I am not very keen on this procedure at the moment

Grtz,

JWS

[eudoniga]

... yep, me too using capt. Bulfer's Guide as a (great) learning aid.

When I don't get to obtain something from the software, like it's described on the book(s), I'm always confronted with the need to make clear if either I did something wrong or there is truly something not working in the software.

Now I know there's at least a couple users with the same problems, and maybe some more.

Thanks again.

[JWS]

Eudoniga,

did you check my other thread about the DES NOW feature? Same story?

JWS

[eudoniga]

You can count me in.

Given the current overspeed issues in VNAV descent, those related to the mach/IAS changeover, I'm actually using V/S mode for descents.

Regards,
Eugenio.

[jrphcien]

eudogina wrote
When I don't get to obtain something from the software, like it's described on the book(s), I'm always confronted with the need to make clear if either I did something wrong or there is truly something not working in the software.


Hello Eudoniga !
Same thing for me, although Bill Bulfer guide is excellent, the PM software is more a generic approach. That book should give us an idea how things should work but as you realize, procedures may be completely different depending on the real software update (U3 and up, u10). So since i am not a professional pilot (only private ) neither a profesionnal programmer, i end up with that same question: my fault or software bug ?
jean-louis

[eudoniga]

... and I think that reading "U10" on the IDENT screen of PM-CDU might be dangerously misleading, if you happen to have a precise description of what the real version U10 is able to do.

Not practical, maybe, but if the replica was labelled like the original, we could better tell what is "in" and what's still "out".

Regards,
Eugenio

[JWS]

, i end up with that same question: my fault or software bug ?
jean-louis

That or just not in the product (although I thought having seen on one of the PM CDU pages that it's up to U10, but correct me if I'm wrong).

V/S for descents doesn't give me a lot of pleasure since PM in combination with CPFlight results in 6000 ft/m climb when pressing V/S. And what do you mean with Mach/IAS changeover? Does IAS change to Mach = 400 (instead of e.g. .68) like with me?

JWS

[eudoniga]

Apart that +/- 6000 fpm for LVL CHG mode is a max limit which can be altered from the MCP .ini file ...
are you sure you're not talking about climbs and descends ... in LVL CHG mode ?
You don't get to those rates in V/S mode; not without your action, anyway.
With my CPFlight & PM MCP, as soon as I select V/S the initial value is 00; then I start by raising or decreasing it according to the needs ... no danger !
In the other option available (see the mcp.ini again) pressing the V/S begins not with zero fpm, but with the current rate of climb/descent.
So unless you're already climbing/descending at 6000 fpm, you don't begin V/S mode with that rate ...

Hope I was clear enough !
;-)

[jrphcien]

hello Eugenio,

Using only raw datas (no LNAV or VNAV) are you able to do a backcourse approach (MCP A/T on, AP on VOR LOC) ? Each time i did try the aircraft initially seems to capture the localizer but then it become erratic ..
In the Bill Bulfer guide, the suggested way is LNAV and VNAV but it is not clearly stated if the other way could work. Flying online on Vatsim i was radar vectored to a Back course approach (so cannot follow flight plan on cdu since atc change....) and the only way i could get to the runway was a DIR TO the IAF with VS mode !
jean-louis

[JWS]

You don't get to those rates in V/S mode; not without your action, anyway.
With my CPFlight & PM MCP, as soon as I select V/S the initial value is 00; then I start by raising or decreasing it according to the needs ... no danger !


Yes I do get those rates:cry: in V/S. I should get 00, but I don't.
I've contacted PM about this but they can't put there finger on it.
All goes well while using PM or CPFlight seperately, but in combo I have this weird problem.

JWS