Hey Gang,As those of you who have read my articles for various magazines will know, I have a real problem with poor implementations of LNAV and VNAV! I have seen some really beautiful sims completely broken by a wobbly LNAV or a VNAV that is far from accurate in its implementation. I should not complain so much as these features use incredibly complex algorithms. In fact, I have only seen PMDG, out of all sim developers, actually have a VNAV profile that matches the real aircraft.So, I spent some time this morning checking out the LNAV and VNAV on the NGX and wanted to share some really interesting observations on the incredible accuracy of the NGX. It is another one of those parts that add up to a really incredibly satisfying whole.Cue a choppy ride into London Heathrow on the BNN4A arrival through Bovingdon. For those unaware of the arrival there are some pretty tough altitude stepdowns and speed constraints followed by quite a sharp turn to align up for 27R, the westerly runway at Heathrow. I also wanted to show you further pictures of the HUD as quite simply, I love it!I elected to fly to localiser capture, from top of descent (at 21,000ft from Manchester) completely in LNAV and VNAV, allowing the aircraft to decelerate based on FMC leg constraints to give the automatics a maximum workout. My only intervention being to deploy flaps at the appropriate junctures to allow VNAV to decelerate further. You might want to try something similar with other sims and notice how few of them actually manage to reach the localiser at the correct speed and altitude after a complex string of restrictions! For good measure, I had some choppy weather and mild windshear throughout the descent.The NGX hit every constraint and speed restriction on the nail using absolutely accurate parameters. A good example of the intricacy - you fly over a waypoint and your next waypoint requires you to slow to 200kts - most sims immediately decelerate when they see the speed restriction ahead. The NGX slows only at the distance from the waypoint that it needs to do so to make the next speed target. No sudden deceleration when the FMC "sees" the waypoint ahead. So if the NGX determines it only needs 6 miles to decelerate to meet the next target, it will only do so 6 miles from the waypoint. Similarly, the vertical profile is perfectly managed to match the real aircraft. Gone are the days in other sims of long shallow descents that are not needed or sudden dives to make the next waypoint. The NGX follows a precise vertical profile that is matched in the real FMC, no fudging of climb or descents but a real profile that will match your cost index economy parameters.if you look at the CDU in the picture above, you will also notice the NGX is also fully RNAV equipped. You can see the required navigational precision and actual navigational precision. In this case, the LNAV track is required to be within an error tolerance of 0.3nm. The NGX is doing fine with an actual navigational precision of 0.06nm, well within safe tolerance. Are these numbers made up? No you will see the required navigational precision is totally accurate for the environment you are flying in, be it oceanic airspace or a tight approach into an airfield. These figures are not made up in the NGX but reflect actual requirements for your approach chosen etc. That then asks the question, is the ANP - our actual precision fudged in any way? The answer is also no, the ANP is calculated realtime from all of the navigational sources. It does change and will change, not randomly but based on realtime navigational monitoring using actual aircraft parameters. If you are flying an RNAV approach, you need to be aware of your ANP! None of this stuff is fake numbers, LNAV, VNAV, RNP and ANP values and data are all calculated real-time based on the mathematical algorithms of the real NG!In short, a whole new world of accuracy never before seen in a desktop sim, if like me you love flying complex approaches!Here are a couple of HUD pictures from flying the ILS into 27R. Notice the difference from when I was in VNAV in the first picture to changing to APP mode? The HUD has automatically decluttered to maximise the approach view. See how the speed and altitude scales have been removed?I am 200ft above the runway at decision height, further HUD guidance has been given by projecting the guidance lines over the sides of the runway. By aligning with the view of the real runway, you can confirm your path. You can also see the 3.0 marker, highlighting the required 3 degree glideslope.The combination of the incredible navigational precision of the NGX, coupled to using the HUD really transforms how we fly approaches in the sim!all the bestJR

Very nice. Thanks for sharing. Nice crabbing on final while still perfectly aligned. Good to see the HUGS still available as a 2D full screen overlay. I really can't get over that its font has been completely revamped. Now it's just marvelous. :( Some airlines fly up to CAT IIIA manually using HUD systems. Whether that's done on NGs or not, I'm gonna try it out when I can. Should be a breeze.EDIT: Question comes up. Suppose that overlay only works correctly for a 1.00x zoom? Talking about 2D here, as in VC it shouldn't be of any problem.EDIT #2... I was wrong. Completely distracted by the HUGS I very much ignored the panel at the bottom, so I suppose it's still the VC just zoomed in. Disregard. Then I pose a different question: Is the HUGS still available as a full screen 2D panel overlay? :( I believe the very first WIP shots of it were like that. Think of the Acceleration FA-18, that's sort of what I mean, go to 2D panel and press W a few times. Pretty neat.

Edited July 23, 201114 yr by badderjet

Looks great thanks for the preview

Good to see the HUGS still available as a 2D full screen overlay.

It is? I don't see how you figured that from the images unless I am missing something or misunderstanding.

It is? I don't see how you figured that from the images unless I am missing something or misunderstanding. Not even sure how HGS could be a 2D overlay.

No it's not, at least not in this shot, I edited my post above. Sorry for the confusion. :(

This is now driving me MAD.Can't wait it fly her into London Gatwick with UK2000 scenery.

Hey Etienne,To answer your question, yes there is still a fullscreen 2D panel overlay (on the W key)all the bestJaneRachel

It was for this very reason I had to return my 'other' NGX to it's manufacturer.For me, THE most important part of flying this type of aircraft is VNAV, closely followed by LNAV.There were just too many small gltches adding up to frustrating flights (and failed flights).ALL at PMDG have my admiration.Thank you!

Thank you very much JR for your time.

To answer your question, yes there is still a fullscreen 2D panel overlay (on the W key)

Hey Jane,thanks for the quick reply. Now seeing it (seems of darker colors) and given the fact that I misinterpreted your first shot as the full screen overlay (kudos to collimation...) makes me think I would in fact stick with zooming in on the VC. Just looks gorgeous enough so maybe the 2D one isn't even better at all. Plus it looks as it was a little distorted, most likely due to aspect ratio. Not happening in VC, plus the colors are so much more readable.Thanks for the follow up!Regards,

Hey Jane,thanks for the quick reply. Now seeing it (seems of darker colors) and given the fact that I misinterpreted your first shot as the full screen overlay (kudos to collimation...) makes me think I would in fact stick with zooming in on the VC. Just looks gorgeous enough so maybe the 2D one isn't even better at all. Plus it looks as it was a little distorted, most likely due to aspect ratio. Not happening in VC, plus the colors are so much more readable.Thanks for the follow up!Regards,

I do find the 2D overlay to be crisp and clear and actually looks much better than my quick screengrab. I had the JPG quality wound quite a way down. Also, don't worry about the aspect ratio. I didn't set my 2D aspect ratio to the widescreen option as I normally only just use the VC to fly in FSX. It was just a quick and dirty image really to show that the HUD works in a 2D overlay, so I wouldn't analyse it in any depth :)

The runway outline on the hugs is simply amazing... do you have the lines on the hugs with every ILS cat 3 airport?!

The runway outline on the hugs is simply amazing... do you have the lines on the hugs with every ILS cat 3 airport?!

yup! it is such a great aid!all the bestJaneRachel

I do find the 2D overlay to be crisp and clear and actually looks much better than my quick screengrab. I had the JPG quality wound quite a way down. Also, don't worry about the aspect ratio. I didn't set my 2D aspect ratio to the widescreen option as I normally only just use the VC to fly in FSX. It was just a quick and dirty image really to show that the HUD works in a 2D overlay, so I wouldn't analyse it in any depth :)

Thanks, wilco! Then my original question shall be revived: Pretty sure the 2D will only work for 1.00x zoom factor? Sometimes I like to reduce zoom to something like .7 in order to get a better overwiew, but it wouldn't be bad if it had to be left at 1.00 in order for the HUGS to function properly. Just wondered.

JR your posts are really a pleasure to read. The life you add to the subject only adds to the sensation, and it becomes easy to share in your excitement over the aspects of the plane you are testing.When I see a new thread started by you, I know I am in store for a great read, and this was no exception. I appreciate the info, and I really enjoyed it.Thanks,Scott

Time to test it on the Ziggy4 into KONT !!!