Severe turns

[Gaz 15]

Hi

I've created a flight plan using SimBrief, and loaded it into FSX and PMDG.  Other plans that I have done work very well with SimBrief and PMDG.

The problem is that sometimes SimBrief generates a severe turn in the plan (see my plan: https://photos.app.goo.gl/hR37w7sLs2rDaycs8 ), and this causes the 737 to go from left to right, over doing it, causing it to constantly to go-over the route so that it has to do another turn back (it essentially oscillates) .  It takes some time before the aircraft is doing smaller turns, and eventually on course.  I've even tried reducing the bank angle, but it was just a try and didn't seem to help.

Anyone can tell me what I'm doing wrong?

Thanks
Gary

[downscc 1,327]

This problem is not isolated to the NGX, the 777 and to a lessor extent the 747 will do this as well.  This is part of the flight dynamics that PMDG has not yet accomplished outside of the box (I think) and it remains up to the default FDE to provide turn physics, which it does poorly.  The easiest way to compensate for this is to wait for the passing of the waypoint, when the 2d waypoint is promoted to 1st, and then LSB that waypoint on top of itself.  Press the LSB twice, and then EXEC.  I usually EXEC when my turn has progress to the point where the heading is almost to the new heading (even if way off the magenta line).  This effectively repositions the magenta line and you avoid the correcting turns.  Another trick I use when the 90-so-odd-degree turn is in an arrival such as arriving EHAM or RJAA and I can reasonably slow her down to 220 KIAS, is to put a custom waypoint 2 nm before and 2 nm mile after the waypoint with the large heading change.  Leave the original.  This effectively turns the sharp turn into a small radius turn that is closer to what the FDE is going to give you.

[Gaz 15]

I appreciate you getting back to me on this... 

Your reply is complicated - you're clearly experienced! Given what you've said, though, I'll try and work out how you do what you've said. 

Thanks! 

Gaz

[scandinavian13 5,192]

19 hours ago, Gary McCluskey said:

I've even tried reducing the bank angle, but it was just a try and didn't seem to help.

Quick note: this won't work in LNAV - it's not meant to. The bank angle selector is only for use in HDG SEL.

What weather program are you using?

[Gaz 15]

I haven't loaded a 3rd party weather program yet, so it's fsx fair weather to be honest - just while I'm training. 

When I fly out of 08R or L from Gatwick, I simbrief puts me on the LAM5P airway. In the fsx flight plan, I can remove waypoint D260J from the route - that is the waypoint causing the most problem. However, in PMDG fmc, it is not listed on the legs page - simply LAM is there, it's like D260J is a sub element of that, and because it's causing the severe turn, it would be good to get rid of it on the fmc, but only lam is there. 

I appreciate you both getting back to me. 

[Gaz 15]

BTW, I didn't know that about the bank angle, thanks. 

[dave_paige 11]

If I might I'll make a couple of suggestions here...

I recommend not loading exporting flight plans from Simbrief into the FMC. Simbrief is a fantastic planning tool and I use it every flight. But I always enter the flight route into the CDU manually. The reason is that, often, things will be missing from the exported plans.

Be careful about your aircraft's speed during departures. Particularly if there are sharp turns in the departure. It's possible that you might have to much energy to stay perfectly on the magenta line during a sharp turn.

I suggest taking a look at the video tutorials by Flightdeck 2 Sim on YouTube. They are done by a real world 737-800 FO/sim instructor. They are very good and he refers to this exact concern in a couple of his videos about takeoff and flying a SID. I highly recommend his channel. https://www.youtube.com/channel/UCZ_X7kk3XrHbl6ZWQ4wpfkQ

[Ephedrin 418]

17 hours ago, dave_paige said:

The reason is that, often, things will be missing from the exported plans.

When both your simbrief airac cycle and your PMDG cycle are the same there shouldn‘t be any issues. At least I have never noticed any and I am quite carefully doing my preflight and route checks...