I've had route discos I couldn't delete either on normal flights. Usually when adjusting a STAR or IAP. I never knew why it happened, although I didn't pause to really look and see if it was something I was doing wrong, but it happened enough that I didn't feel like it was me.Only happens in the 744 (FS9), not the 737NG or others I have like that.

Not sure what else you could try now.Maybe using something else to build the flightplan and making a custom waypoint instead of the n70 waypoint and seeing if that works.Sorry I couldn't be of more helpRichy

something different: How can there be 60 nm between 90N74W and 90N106E? It's exactly the same point. Or am I missing something here?Tom

something different: How can there be 60 nm between 90N74W and 90N106E? It's exactly the same point. Or am I missing something here?Tom

I have said before:>Hi Paul,>As I described on the first line, the N90 isn't N90 00.0 but N89 30.0. >The North pole is the middle of 60NM between N90W074 and N90E106.Sincerely,Kan-ichiro Fushihara

I have said before:>Hi Paul,>As I described on the first line, the N90 isn't N90 00.0 but N89 30.0. >The North pole is the middle of 60NM between N90W074 and N90E106.Sincerely,Kan-ichiro Fushihara

Hi Kan-ichiro Fushihara,Real life Boeing FMC's have issues near the North Pole, plse read http://www.boeing.com/commercial/aeromagaz...v_by_model.htmlSo maybe an omission in the PMDG progamming might cause this hick up.Also check out http://williams.best.vwh.net/avform.htm#CrsIn short: near polar flights are practically impossible/difficult to compute due to A) fast changing heading references, and :( some trigonomical functions approaching infinity near 90 degrees N/SRegards,Willem

Dear Willem,Thank you very much for your valuable information. I have to study it.

In short: near polar flights are practically impossible/difficult to compute due to A) fast changing heading references, and :( some trigonomical functions approaching infinity near 90 degrees N/S

Although I have intentionally avoided to make a waypoint with the North Pole itself (N90 00.0), I understand clearly LNAV controlled navigation of the PMDG 747-400X is very unstable near the Pole. It seems that I have guessed right.Sincerely,Kan-ichiro Fushihara

Dear Willem,Thank you very much for your valuable information. I have to study it. Although I have intentionally avoided to make a waypoint with the North Pole itself (N90 00.0), I understand clearly LNAV controlled navigation of the PMDG 747-400X is very unstable near the Pole. It seems that I have guessed right.Sincerely,Kan-ichiro Fushihara

You are welkom,You don't have to study the trigonometry behind the FMC calculations: you can reduce the whole matter by asking yourself this (Zen) question:- What is your heading when you are directly over the North Pole?When you find the answer, you can appreciate the problems involving FMC track calculationsGood Luck and happy landings.Willem