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Guest Totalbeginner

Can't perform go around in 744

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Guest Totalbeginner

I've read the article in the customer support section of the PMDG website, but I still can't perform a satisfactory go-around with the 744. Can somebody help, or tell me what I'm doing wrong!!!With the A/P in CMD and LOC/GS capture I hit TOGA once at DH. FMA displays the following...THR | TOGA | TOGAThe throttles increase to about 98% N1 and the aircraft pitches up. I select FLap 20 and retract the gear once there is a positive climb.At this point it slowly turns to a bag of nails, every time!!!!The FD commands 25 DEGREES pitch!!! nose up which is way to excessive. The speed starts to reduce and then the aircraft STALLS!!!!I was under the impression that with "one click" of the TOGA switch the ROC should be around 2000fpm.I've tried doing a G/A by pressing TOGA twice, but with 25 degrees pitch and FLAP 20, the aircraft still stalls with THR REF.Where am I going wrong, or is this a program error??????Thanks in advance,Martin Neep

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Try pressing the TOGA switch twice initially. You are correct in that the AP should maintain 2000 fpm. Unfortunately it tends to pitch up and eventually stall. This is a known issue. The only way I can get a correct (or near correct Go around) is to hit the TOGA twice on the initial Go around.It would be nice to see this corrected as it really does detract from an otherwise splendid and accurate aircraft model.


Cheers

Steve Hall

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Martin...Do you have a higher altitude than your current altitude selected on the MCP?Is your joystick throttle advanced? (the joystick may be overriding the A/T).Hope this helps.Cheers.Q>

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Guest Totalbeginner

>Martin...>>Do you have a higher altitude than your current altitude>selected on the MCP?>>Is your joystick throttle advanced? (the joystick may be>overriding the A/T).>Q>It's definately nothing to do with the above. I'm pretty sure this is a program error. I tried the other suggestion of double clicking the TOGA switch at the very isntant a G/A is initiated but it makes no difference, the aircraft still stalls. The only way around this is to disconnect the A/P and hand fly the profile.Another thing that I've noticed is that when I go-around, the ILS frequency disappears from the NAV/RAD page of the FMC and has to be re-entered, does this happen in the real aircraft, and if so, why?Oh, and one last thing...Lets say you execute a G/A and decide that you have reached your min fuel and need to divert. How do you then select CLB thrust so that you can climb enroute to your alternate. I've tried pressing the THR switch and using the THR LIM page of the FMC but it doesn't work???Thanks again,M. Neep.

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"It's definately nothing to do with the above. I'm pretty sure this is a program error."So you're saying that you DO select a go-around altitude before pushing the GA switch?Do you let the aircraft change vertical direction before retracting the flaps?"Another thing that I've noticed is that when I go-around, the ILS frequency disappears from the NAV/RAD page of the FMC and has to be re-entered, does this happen in the real aircraft, and if so, why?"I'm not sure it should disappear, but there is a tune inhibit for about 10 minutes (It can be manually overridden, however). I guess this is to prevent the FMC trying to retune during approach to a wrong frequency without giving the pilots the chance to check that frequency."Oh, and one last thing...Lets say you execute a G/A and decide that you have reached your min fuel and need to divert. How do you then select CLB thrust so that you can climb enroute to your alternate. I've tried pressing the THR switch and using the THR LIM page of the FMC but it doesn't work???"I assumed that changing climb modes (which you have to do somewhere between hitting GA and reaching the missed approach altitude) would put the aircraft back into CLB. We may have to ask the pilots what happens in this case as it's not covered by my manuals.Sorry, it's difficult to analyse your problem when the GA function is working normally on my computer.Perhaps you can post some before/after screenshots?Cheers.Q>

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There is something definitely amiss here. How long after selecting TOGA does it all go wrong?Passing 400 ft select LNAV and passing 1000 ft select VNAV. Selecting another pitch mode should get you out of GA thrust. If GA remains illuminated then select THR on the the thrust switch.The ILS should remain tuned.I hate to say it but you may need to re-install.


Cheers

Steve Hall

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Actually, yes, I am running the -400F.The video is a little difficult to see. Just wondering what the EICAS Caution messages is?I'm also wondering if you retracted the flaps too soon (perhaps the pilots can comment on this?) I would have waited a few moments for my speed and pitch to stabilise before retracting flaps. Also, in the real world go-arounds I've seen, there is a significant delay between flap and gear retraction (or is that an oversight on the part of the real world pilots :( ).Cheers.Q>

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It is a little difficult to see as the video is blurry. The quick selection of flap 20 should not be an issue and in fact is almost the real world pace. I could not see the annunciations on the FMA so I cant comment on that aspect. What I did see is fairly typical of a GA in the PMDG 747-400 (I haven't tried one in the freighter).The only way around this is to select LNAV and VNAV (or another pitch mode). It is a real shame that this area cannot be tidied up by PMDG but I guess their plate is full.Q, as for the RW delayed retraction of the gear this is because it is normal practice to wait for a positive climb before retraction and also an early selection will cause the gear config warning horn to sound which is very distracting.


Cheers

Steve Hall

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Guest Totalbeginner

Ok, problem solved!I installed the -400F and it performed the G/A flawlessly!

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Guest Jake Lee

Just a shot in the dark here. You think pressing FL change will put you at 2000fpm climb?-- Jake

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If the 747F performs the GA correctly would it not be possible to have this piece of programming logic/code issued as a patch for the pax version? Sure is darn annoying.


Cheers

Steve Hall

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Guest fjshepherd

I'm wondering that with all that up trim on approach, maybe it isn't trimming that out on the GA, and hence the excessive pitch-up... but you would think that the autopilot would re-trim the aircraft in any case, and that the upwards trim wouldn't be that much. It is a shame if it is a PMDG issue...

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