I haven't tried that exactly.
Haven't done any long flights in this bird recently, quite busy with other things.
Sorry, I wouldn't know the answer to your question.

Lars

JayG: I'm in the same boat as you right now with thew 727. Auto approaches and ILS's...
Today I managed my first ILS approach, I'm not pround of it because I landed faaaaaaaaaaar away from the runway That is the plane began it's auto descend too soon. The capture of the ILS heading was straight on. But the maintaining of altitude,unless I'm doing/ expecting something (?) was way too soon. It landed the plane a good 5 miles out in front of the runway?????

I am having difficulty with the autopilot properly capturing localizers and glideslopes. With pre-intercept conditions of: AP set to Heading Hold and Alt Hold, course needle set to desired course (final approach course) and approaching the localizer on a heading resulting in 20 degrees or less for an intercept angle and an altitude far below the GS, I switch the AP to "Auto/GS" when cleared for the approach.

As the localizer needle-segment "comes alive" on the CDI and starts to move toward a centered "on course" indication, the AP does *nothing.* It continues to do *nothing* until the CDI indicates that we have just flown through the localizer... then it abruptly turns the airplane back toward the localizer using max bank angle... flies back through the localizer... overcorrects again... flies through the localizer again... and basically zig-zags around the localizer all the way down final.

Meanwhile, the GS needle begins to move down the side of the CDI. So, true to its disposition, the AP does *nothing* until we have flown through the GS, at which point the AP abruptly noses the airplane over into a dive... and we porpoise endlessly, flying through the GS at least 5 times as we zig-zag around the localizer. Sometimes we get near the runway, sometimes we don't.

In short, my AP seems to stay about 2-3 seconds behind the airplane at all times. It's not my computer- I have great framerates (minimum 25 fps) at all times and no scenery-load "glitching" even with UTX and GEX running... nothing about flying in FSX is "tardy" for me except the AP in this particular airplane, so my computer is not 2-3 seconds behind the Sim... it's really just the AP that can't seem to keep up.

Even worse, several passengers have sent gratuitously-nasty letters to my airline, featuring my name and using unjustified phrases such as "ham-fisted oaf" and "needs to go back to his previous career as a blacksmith" and "surprised the wings stayed on the airplane." Management has taken to occasionally asking me if I miss my days of being a FE on the 727...  

I have carefully read the manuals (Systems and Ops), as well as the excellent mini-tutorial at the head of this thread, and I believe that I am setting everything correctly for LOC/GS captures. My expectation is that the old Sperry will "notice" the impending LOC and GS capture as soon as the needle comes alive and begin turning toward the course (or pitching down toward a normal ILS descent gradient) as the needles get a dot or two BEFORE center, not AFTER center. The result would be a relatively smooth and accurate capture with MINIMAL "hunting" back and forth.

Since there are people here who say that "everything works fine for me" can someone please tell me if Auto/GS with settings as I described above works for you without zig-zagging and porpoising all the way down final while using up all the barf bags aboard, or if I am setting something incorrectly?

Thanks!

HoggyDog wrote on Dec 12^th, 2009 at 7:20pm:



Hello,

Concerning Auto/GS approach mode, it works without problem when the plane is EMPTY (just the 3 officers + 3* 20 or 30 percent of fuel)

I made several touch and go at KORD with not problem.

BUT if the bird is full passengers + some luggages in cargo + 10 or 20 percent of fuel (typical config after a trip), it seems react like you wrote.

Maybe a clue for some fine adjustement in plane.cfg or other files...!?

Have you tested with an empty plane ?

Regards.

Richard.

Richard Portier wrote on Dec 12^th, 2009 at 8:48pm:


Richard, thanks, it never occurred to me that aircraft weight would have anything to do with AP performance, and I have NOT tested with an empty airplane- all of my approaches in this fine bird have been at the end of a 1-2 hour flight that started with full fuel and about 50-80% passenger/baggage loads.

I will do some testing with an empty airplane and see if that cures the AP problems, but even if it does, I hate to have to placard the AP "WARNING: APPROACH MODE UNUSABLE UNLESS AIRCRAFT IS EMPTY" 

I hear you loud and clear on that.

Regarding what Richard said, I always make sure I'm below MLW so that may explain why I've been able to capture the localizer ok. 

Even when I get the localizer, I'm still hit or miss on the glideslope...it seems like if I do anything out of the ordinary the AP forgets what it's supposed to do.

Fortunately hand-flying this aircraft is very doable

Help! :S

When enabled, the autopilot in the 727 should keep the pitch angle. My 727 can't do that. Why? A bug?