3 hours ago, MarkJHarris said:

Nice example of the B737NG, but if you've flown the real aircraft, you'd know it really can't follow the magenta line for toffee in the low altitude departure phase. 

You often find yourself in that initial turn out while still accelerating and it ties itself in knots trying to follow it as speed changes and you clean up.

So I'd say it was probably more realistic than not.

 

 

That is interesting - why is that I wonder?

I haven’t flown the PMDG 738 for a long while but have been doing quite a few bits in the 744 and can’t say I’ve noticed the effect, even after Dan pointed it out.

Quote

Nice example of the B737NG, but if you've flown the real aircraft, you'd know it really can't follow the magenta line for toffee in the low altitude departure phase. 

You often find yourself in that initial turn out while still accelerating and it ties itself in knots trying to follow it as speed changes and you clean up.

That reminds me of the Dopek 2W departure at EGNM Leeds Bradford. When I attempted that for the first time in the 737-600 NGX, it just gave up and started plunging towards the ground!!

It's probably because the older NGs have seriously slow CPUs in the FMCs that take a few seconds to work stuff out, and also you're trying to drive a heavily modified and butchered 1965 concoction of spare parts with a 1980's computer. Don't get me wrong, I like flying them, solid, safe and reliable. They are however cramped, dirty for the most part and compromised in many ways.

Best part of the NG is the drip tray. Look at the bottom of the Overhead panel. on the font edge is a trim panel running full width with three drain lines. This catches condensation in the descent and stops it raining on the pilots. Brilliant idea! 

1 minute ago, Christopher Low said:

That reminds me of the Dopek 2W departure at EGNM Leeds Bradford. When I attempted that for the first time in the 737-600 NGX, it just gave up and started plunging towards the ground!!

Sounds more like a bad trim axis or something, honestly...

The ideal way to get the NG to correctly follow these things is to introduce speed limitations in the legs page. This keeps it slower in the turns and allows it to follow the lines. Often, such as LAMIX from LBA, you'll see it drawn with a overshoot and turn back onto the radial specified in the SID. By putting a 220B/ in it will redraw it neater and fly it neater too. Just saying.....

Quote

Sounds more like a bad trim axis or something, honestly..

I am fairly sure that someone else confirmed that the Dopek 2W departure was acting a bit strangely. I may have to test it again, as that was quite early in my "PMDG autopilot experience" days.

Edited July 18, 20187 yr by Christopher Low

1 hour ago, MarkJHarris said:

The ideal way to get the NG to correctly follow these things is to introduce speed limitations in the legs page. This keeps it slower in the turns and allows it to follow the lines. Often, such as LAMIX from LBA, you'll see it drawn with a overshoot and turn back onto the radial specified in the SID. By putting a 220B/ in it will redraw it neater and fly it neater too. Just saying.....

This applies to some arrivals as well.  The one of many that comes to mind is the 90 deg turn on the RJAA ELGAR arrival at MELON.  Left alone, the VNAV would have you above 10,000 at those descent speeds but if you try to fly it that way you end up a mile off track.  Best to dial in something like 230/8000B, which if you look at the actual traffic ground tracks this is closer to what ATC is clearing.  It is always a good idea to evaluate published terminal procedures with a dose of reality and not blindly follow the automation.

Edited July 18, 20187 yr by downscc