North Pole in the 787 on Xbox

[GimbalAxis]

After seeing a video about real world polar flights (Tokyo to Oslo, over the North Pole, I think) I decided to try my luck from PANC Anchorage to ENGM Oslo, on Xbox X in the 787-10. I flew due north on the 150 West longitude to 90N150W (there is a waypoint NOPOL at 90N000W which is essentially the same point - once you are at 90N all the longitudes converge to a point).

(I’m assuming all coordinates are Magnetic and not True, because there doesn’t appear to be a switch for True on the 787)

Here was the flight plan in Simbrief:

PANC/07L FFITZ DCT BTT DCT PABR DCT 80N150W DCT 85N150W DCT NOPOL DCT 85N010E DCT 80N010E DCT 75N010E DCT ELSID M609 BELGU BELG3L ENGM/01L

And wow do things get weird once you get north of the 82nd latitude. First symptom, the sounds go completely silent in external view on Xbox, and, the camera movement gets locked somewhat. If you move camera up, it won’t go down - all you can do is reset the view. Interestingly the drone camera is fine, sound and movement all normal.

As you approach the 85th latitude, the ND starts to freak out, slowly at first - it will start to zoom out on its own trying to render the path after the pole. It even has trouble rendering the pointer for the plane, it jumps around also.

As I got above 89N, things got really crazy. Apparently there is no “true” heading in the WT 787, and the magenetic reference goes nuts - to continue straight you have to disengage LNAV and just try to fly straight until you are past the pole…

Very near the pole, without explanation, the altitude starts to go funny also, the plane started an uncommanded climb, then descent, but the vertical deviation indicator seems to go in the opposite direction, the plane gives all kinds of warnings about altitude, and all you can do is just try to fly straight until you are past it. if flying at night, you just have to turn LNAV off for a while and keep level to fly straight.

Once you get below the 85th again, you can sort of restart LNAV and try to find your flight path, and once you are below 82N or 81N the sound and camera functionality of external view also returns, slowly.

Too bad there is no icecap rendered (at least not on my flight).

[NixonRedgrave]

That is freaking awesome!

The QA tester in me lives for this sort of crazy!

[GimbalAxis]

It’s a long flight, but I’ve learned to use the Sim Rate increase / decrease to make time go faster for the long uneventful legs of the flight.

I think the issue with the poles is a combination of the navdata, weather data and how the sim converts what I presume started as a 2D flat model to work on a 3D sphere. If the sim sees the world as a flat sheet of paper, then 90N (and 90S) are the edge of the paper, and it doesn’t really know how to wrap around to the other edge without some traumatic fluctuations. I forgot to mention the crazy shudders at the closest point - I think if I had actually hit 90N it might have crashed the sim or the plane.

Edit - I just realized from another screen shot I did hit 90N, and in the screenshot I notice that the cabin pressue is spontaneously rising (to be precise, pressurizing to a lower altitude), the plane appeared to bank and turn right, but on the outside view, it was skewing left.

And, the entire flight plan collapsed in to a… singularity? Even though the ND Range is 20 nm, and I’m at the north pole, I can see the text label for Oslo runway 01L under the plane’s indicator… which is no longer where it should be. Wondering if I can teleport to the South Pole from here. Somebody call Fox Mulder.

I’ll have to do it again with a video.

I hope - suggestion to anyone listening… - perhaps they can “harmonize” an 80nm ring around the poles to make them a bit more naturally accessible?

[LKFJP]

It used to be that the FMS would have a “polar grid mode” that the flightcrew would switch to north of about 82N (and south of about 82S). I recall that Airbus even did a proving flight on the A380 over the north and south poles, landing in Iqualuit along the way to prove cold weather operations) to ensure that the avionics would handle the convergence of the meridians at the poles properly. I don’t know how that was handled on later designs like the 787 and A350, but it is an area of navigation that requires special attention.

[GimbalAxis]

I managed to do another flight, RJTT Haneda to EFHK Helsinki, and this time I really did find the North Pole - one giant tile with perhaps the last of the polar ice cap?

RJTT/16L ROVE2A INUBO Y808 PUTER A590 POWAL DCT OPAKE DCT MARCC DCT JUJXI DCT 80N165W DCT 85N165W DCT 89N165W DCT 90N000E DCT 85N020E DCT 82N020E DCT 80N021E DCT BARUX DCT IBOSU Y86 LUSEP LUSE4M EFHK/15

Within a few NM the engines pulled back thrust on their own, and the plane started climbing, while the VSI went down… then some massive shudders going over the pole, then the opposite, plane descending while VSI shows a climb. I tried to take it out of LNAV but it would not let me, and as it turns out it was ok.

Unfortunately due to the limitation of Xbox, the video ended just as I was crossing the pole and it did not capture the shudders. Video:

2024-04-28 MSFS 787-10 North Pole (2nd trip)

[LKFJP]

@GimbalAxis

I managed to do another flight, RJTT Haneda to EFHK Helsinki, and this time I really did find the North Pole - one giant tile with perhaps the last of the polar ice cap?

There seems to be a volcano erupting there, too?

[GimbalAxis]

Just clouds - but I’m sure the math breaks at that point where longitudes meet, creating a volcano of contradictory data.

I think I’ve figured out part of the weird behaviour. The barometric pressure in the sim seems to change AT the pole in a way that makes the plane think it is climbing (when in fact it is level), so the auto throttle cuts power in order to descend, and starts pressurizing the cabin. Then as you pass the pole, the opposite happens - the barometric pressure changes again so now the plane is too low and must climb.

[CasualClick]

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