Felix448

@Cammac Thanks for taking the time to give a thorough answer on the topic! I was already kinda expecting that the A300 isnt perfect with the AP on profile mode (generally), but this clears up the question. Also thanks for linking the specific video, I was clicking through some of the training videos but didnt find the right one yet. I dont know how much time everyone behind the scenes at IniBuilds has. Maybe developing a small PDF that comes with the aircraft which answers some of the more tricky questions would be great. Kinda like a quick reference before heading to forums etc. Best Regards, Felix

Yeah, thats just the community attitude we all need. Amazing toxicity. 👍 So does anyone have a *real* answer or do we just continue to get replies that basically say nothing? If the reason for this is so obvious and it´s well accepted that the A300 just cant do it. I´m sure someone could explain in a few sentences why the issue is so apparent? By the way, the manual states that the aircraft will vary with the speed on descend, but nowhere that it´s unable to follow the FMS´s vertical path. Regards

Hello, I have a few questions regarding the IniBuilds A300, specifically when it comes to descending and how the AP and FMS are working together. A slight bit of introduction as I havent been around in the forum at all yet: I´ve been flying in simulators (P3D / DCS) for a few years now and have been using most popular addons from the common devs. Whether it be the FSL Concorde, 320 series, FTM Maddog X, Majestic Q400, PMDG aircraft and some more specific stuff. I believe that I have built quite a good knowledge over how different aircraft respond and where there are differences between modern and older systems. I´ve picked up the A300 a while ago, together with XP 11 and Active Sky, to see what XP can do and because I´ve always wanted to fly an A300. Especially since yours has been so highly regarded. I´ve done 6-7 flights now and still cant get around why the AP is behaving so... wacky... in PROFILE descend mode. A quick glance in the A300 FCOM section for Profile Mode: Now, what usually happens when I reach T/D is that I quickly press FL/CH and then change back to PROF upon which the FMA shows P.DES. The aircraft starts to descend, but can hardly stay on the vertical path computed by the FMS. It does recognize speed limits and altitude constraints, but in between it has a very hard time and is constantly either over or under the path. Sometimes quite severe, sometimes only slightly. It´s seems to be constantly fighting itself, often also going into 3-5° nose down descends. (Instead of just easing off the engine power?) I was just on a flight, descending down to FL100 where, for the next 10 miles after reaching the next waypoint, there was a restriction to stay above FL100 @ 250kts. The aircraft was already down to 250kts and going through FL120 with around -1500fpm to reach FL100, still before the waypoint with the mentioned restriction was reached. Instead of just smoothly going down as there was enough room with a few miles ahead, the FMS constantly asked for "more drag". This simply wasnt necessary and (in the end) the aircraft reached FL100 normally without the speedbrake and also still held 250kts. Going down further to 4000ft to intercept the ILS, it´s often still the same thing. The A300 reaches the requested altitude at CI, but HOW it does it always confuses me. It´s always a good bit above or below the vertical path and almost never exactly on it. Why is the AP struggling so much with the FMS paths? Even something as similarly old like the MD-80 can stay on it´s calculated vertical path as long as there´s no strong tailwind. This behavior is kinda annoying, especially when flying online, there is just very little predictability how the AP will handle a descend given by the FMS. This often causes that I have to manually manage my way down with V/S / SPD. (Which is fine, but why isnt the AP capable enough to do it´s task? If it´s actually like that in real life, fair enough. But I cant really believe that there really is such a huge problem here, so far.) What I also noticed: The vertical path indicator on the right side of the ND immediately shows "V/DEV" no matter if the aircraft is spot on the diamond or above / below it. Is there any reason for this? Thanks very much for any help in advance. Best Regards, Felix