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JSACKS

Arghhhh, my 747-400 Go-Around acts strangely !

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I've been trying to execute a textbook GA (in FS9) based on PMDG tutorials and wiki ops instructions and have succeeded somewhat but several things keep going wrong during the procedure. I tried 6-7 TOGA procedures at three different airports this evening using an FMC flightplan for two of them and a plain vanilla, non-FMC ILS approach on the third one. First, when I hit TOGA once, I get HOLD on the FMA instead of THR. (I do get TOGA | TOGA on the rest of the FMA). Power does rise however and I observe the letters GA are lit up on the Upper EICAS.Next (within 3 secs or so), the a/c pitches up to 2000 fpm and IAS increases hesitantly a bit, but then suddenly yanks to 4000-4500 fpm and speed bleeds slightly to about Vref30 as the plane climbs sharply. The climb rate can remain at 3000-4000 fpm or it might abate to around 2500-2700 fpm up to the MCP ALT level (usually 3000').I raise flaps to 20 as soon as the TOGA mode kicks the N1 up steeply.I then raise gear a couple of moments later.At about 500 AGL, I hit LNAV or HDG SEL (rwy hdg typically)At about 1000 AGL, I hit VNAV or FLCH and adjust speed manuallyAt some point during these climbs, the FMA changes from HOLD to THR REF without my touching anything else to do with power and N1 goes to 103-105%. The full thrust busts my pre-set MCP ALT by about 200-250 vertical feet every time.I manage not to stall or otherwise fall out of the sky but this is not what the PMDG procedure tells me should happen. I am sweating all the way up trying to keep control and get things smooooth!Also, I observe that sometimes, the left FMA reads SPD instead of THR or THR REF during the climbout and the magenta speed bug on the PFD FALLS by itself (i.e., magically) to 10-15 knots BELOW my Vref speed (and then the bug increases by itself about a thousand vertical feet later although the speed of the aircraft remains at about Vref30 or a few knots higher during the initial climbout).I also find that once up and at my GA altitude, where I've intervened to place speed at 200 with flaps 5, LNAV does not actually work and nor does HDG SEL act to turn the aircraft where I wish to send it. I have to disconnect the AP momentarily to seemingly "refresh" it and then reconnect the AP and then the HDG SEL function works.I have so far not tried a GA hitting the TOGA button more than once during these procedures. I don't know what that would do. Perhaps I shall try that tomorrow.Is the above report unusual for FS9? My Fs9 rig works perfectly and the PMDG Queen has always functioned pretty perfectly. But this TOGA procedure has me rather stumped with the way it behaves.Appreciate any info or guidance, thanks!Jonathan


Jonathan Sacks

Dell XPS Gen 4, Pentium IV Northwood extreme 3.8Ghz, 3Ghz RAM, eVGA 7900 GTO,

12 GoFlight modules plus MCP-PRO AP and EFIS, GF pedestal, CH rudder pedals,

CH throttle quadrant, 42" LG LED, 24" DELL LCD, Windows XP, FS2004, FSUIPC 3.96

FS Autostart 1.1 (Build 11), FS Navigator 4.6, UT, FE, GE, REX, PMDG, Level-D, PSS, etc.

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Pushing TOGA twice gives you MAX go-around thrust. I get scared using TOGA (especially online in busy airspace) Last night I had to perform a missed approach at Heathrow on Vatsim due to guy in front not vacating. I disconnected automatics and flew it manually. The problem I have found is it can be unpredictable, every now and then I will position myself at remote airportsoffline and just practice engine failures go arounds etc sometimes she flies smoothly in the go around other time I have to take over.The only difference I have found is the weight of the Aircraft.Rob


Rob Prest

 

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The GA procedure should be a piece of cake if procedures are followed and work, but it is not so due to the strange behavior of the a/c and systems in the GA situation I have described above. I am just wondering if it's me or if this is FS9 or the Queen doing weird stuff.[i should also note that I have checked my thrust quadrant and all power levers are set to the idle detent before I hit the TOGA button so I don't think it is a question of any spurious signalling.]Jonathan


Jonathan Sacks

Dell XPS Gen 4, Pentium IV Northwood extreme 3.8Ghz, 3Ghz RAM, eVGA 7900 GTO,

12 GoFlight modules plus MCP-PRO AP and EFIS, GF pedestal, CH rudder pedals,

CH throttle quadrant, 42" LG LED, 24" DELL LCD, Windows XP, FS2004, FSUIPC 3.96

FS Autostart 1.1 (Build 11), FS Navigator 4.6, UT, FE, GE, REX, PMDG, Level-D, PSS, etc.

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Guest Eek

Using TOGA has been unpredictable for me, as well. It's busted my GA altitude every time I've tried it (I've never hit it twice to get full thrust. Once is plenty.:-eek )I've never left the AP on after busting altitude, to see what happens next. If I have to go around, I disconnect the AP and advance the throttles manually. I only use TOGA on takeoff.EwingKATLAlcohol, Tobacco and Firearms should be a store, not a government agency.MSI K8N Neo2 PlatinumAMD Opteron 185 2.6 Ghz Dual Core2GB Kingston HyperX (2X1GB) Dual Channel DDR 2-3-2-6 @ 1TXFX nVIDIA GeForce 7900 GS 256MB DDR3 AGPSound Blaster Audigy LSSilverStone Decathlon 750W +12v@60A +5v@30AFS9 on WinXPPro (SP1)

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Well, good to know it's not just me then--even though it remains frustrating. I'd say given the difficulty of controlling a GA normally with the AP it probably is best to disconnect the AP and the AT and hand fly a GA, and reconnect the AP when things are stable and level again much higher up.Jonathan


Jonathan Sacks

Dell XPS Gen 4, Pentium IV Northwood extreme 3.8Ghz, 3Ghz RAM, eVGA 7900 GTO,

12 GoFlight modules plus MCP-PRO AP and EFIS, GF pedestal, CH rudder pedals,

CH throttle quadrant, 42" LG LED, 24" DELL LCD, Windows XP, FS2004, FSUIPC 3.96

FS Autostart 1.1 (Build 11), FS Navigator 4.6, UT, FE, GE, REX, PMDG, Level-D, PSS, etc.

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Guest M-Sauce

Hello JS;The PMDG 747-400 is a great add-on, but certain "functions" are not well simulated. The GA mode, for example, is one of them.It is a very accurate product, so much so that I use it for practice when I have a checkride coming up or when I haven't flown in a while (which is pretty often when you do long-haul patterns). Our GA procedures are as follows; When you want to execute the GA, the pilot flying calls out "Go-arround, set thrust, flaps 20". At the same time, he presses the GA buttons once and ensures the thrust is increased by the AT. The modes should change to THR | TOGA | TOGA. THR mode will provide enough thrust to give you 2000 FPM, TOGA in roll mode will provide track hold (from when you pressed the button), and TOGA in pitch will provide Current airspeed to a maximum of Vref+25kts.So far, so good. PMDG simulates this pretty well. The problem comes in the accelleration phase of the GA. The way we do it is that at 400 AGL we select roll mode desired. With the PMDG, if you select LNAV, depending on how the procedure was built and your actual position, 9 out of 10 times it will deny LNAV and tell you that you are not on an intercept track. Fine, small agravation but not that big a deal. Stay in TOGA for runway track, or use HDG select to get the airplane going in the right direction.The real problem starts when you try to accelerate. The way we do it is to slect Vref+100 or 250kts, or speed restriction on the MAP, whichever is lower. The problem is that the airpeed bug on the PMDG is "un-movable" in the TOGA mode. You start winding it up and it just snaps back. That is inacurate, the airplane does not do this. By our procedures, we don't select a vertical mode (VS,VNAV or FLCH) until we are at flaps 5. Anyway, I've brought this up to PMDG when I first bought the simulation about 2 years ago, but they ignored my posts on the subject. The fact that they have pretty much moved on to a FSX 747-400 product pretty much guarantees that they will not be fixing any more bugs on the FS9 version. It is that simple. It is still a great product and I use it all the time, but you also need to know its limitations. I would be willing to pay 5 times what it costs if it was fully functional, but I don't think other people would.Mariano

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I don't even get as far as THR | TOGA | TOGA on my FMA. I get HOLD | TOGA | TOGA every time. Why? I have no frickin' idea ! But I still do get GA power as N1 rises to at least 100% and slightly over every time. It changes to THR REF on the way up somewhere. The incorrect automatic speed bug re-set to Vref minus 20 at TOGA activation is terrifying. The speed bug re-sets itself higher as I climb and the speed might actually climb somewhat above Vref 25 or 30 on the way up. I then go into FL CH mode and bug up the speed to 200-210 knots and manage the flaps.Anyway, good to know it's not just (entirely) me and that this is obviously a bug. I don't mind it that much. It's just that I have reached a point where I wanted to gain some real mastery over certain key functions and it would have been nice if the GA function did actually work as per the PMDG tutorial and manuals.I have learned to control a GA both manually and with automatic flight now so I am reasonably satisfied that I can simulate the condition. This Queen is still a marvel and I am very happy with her.Jonathan


Jonathan Sacks

Dell XPS Gen 4, Pentium IV Northwood extreme 3.8Ghz, 3Ghz RAM, eVGA 7900 GTO,

12 GoFlight modules plus MCP-PRO AP and EFIS, GF pedestal, CH rudder pedals,

CH throttle quadrant, 42" LG LED, 24" DELL LCD, Windows XP, FS2004, FSUIPC 3.96

FS Autostart 1.1 (Build 11), FS Navigator 4.6, UT, FE, GE, REX, PMDG, Level-D, PSS, etc.

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