Finnair to Tokyo

[talmacapt]

I am not sure where to put this.

I was looking at fr24 earlier.

The, today, Finnair flight (x 2) HEL - NRT (AY71/73? can't remember) used to, generally, route over Russia.

For obvious reasons, it cannot do that at the moment, and has routed, roughly, due north but has disappeared from fr24.

There are probably no tracker north of Spitzbergen.

It was showing, earlier, as arriving in NRT some 4 hrs ahead of schedule despite leaving on time.

I am surprised but await the suggestions of the great minds on the site, I am a mere amateur!!

[TheGreenGoblin]

There is something of the Matryoshka doll about such a remarkable reduction in journey time, i.e. that which looks big, contains a smaller journey... They couldn't have opted for a great circle route over Russian territory for Narita after all?

https://www.greatcirclemapper.net/en/gr ... ft/68.html

[Undried Plum]

FIN71 is going almost to the North Pole:

8200N/02000E 8930N/06000W DEKMO 8000N/16800W 7500N/16800W 7000N/16800W JUJXI MARCC R338 NATES R220 NRKEY R220 NANAC R220 IXE R211 SWAMP

Same-same Fin73
8200N/02000E 8930N/06000W DEKMO 8000N/16800W 7500N/16800W 7000N/16800W JUJXI MARCC R338 NATES R220 NRKEY R220 NANAC R220 IXE R211 SWAMP

Fin 74 coming the other way is going:
POWAL OPAKE MARCC JUJXI 7000N/16800W 7500N/16800W 8000N/16800W DEKMO 8930N/06000W 8200N/02000E BARUX IBOSU Y86 LUSEP

I guess the Scandi airlines are picking up a lot of business to Tokyo because of handy proximity for the near-Polar route which goes on the Septic side of the Bering Straights.

[TheGreenGoblin]

So not a Cobra Ball scenario then. No Fairchild manufactured long aperture cameras whirring away from disguised pods.

[talmacapt]

Applying brain and thinking about it.

I do not know how fr24 calculates local times.

Based on the time and distance to go, when I noticed the apparent 4 hr ahead of schedule, I calculated that the actual arrival time would be some 4hr later than shown, ie about schedule arrival time.

I suspect that somehow an error occurred in converting to local time.

Helsinki is UTC + 2 and 2x2=4 may have something to do with it!!

[tango15]

For reasons which have been explained to me, but I never fully understood, FR24 can be very inaccurate. Whilst working as an ops minion some years ago at LTN, we had FR24 on the screen in the office. I had been asked to go out and meet an inbound Wizzair aircraft and the reg was showing on the screen as HA-L.. (can't remember now). When it taxied onto the stand, I realised that it had a different reg from what had been shown on FR24. I had a chat with the (English) captain, who was as clueless as me and then went back to the office and changed all the paperwork. I spoke to a mate of mine, for whom this stuff is meat and drink, but he kept mentioning the word hex, so I assume a witch's spell had been put on the aircraft. I know that witchcraft was (is?) widely practised in Hungary, so it made sense. I cannot offer a more rational explanation.

[talmacapt]

I see today's return flights have just about disappeared off the top of fr24 near the International Date Line.

They will no doubt reappear to the north of Spitzbergen in a couple of hours.

Seem to have got the time correct today!!

[talmacapt]

If anyone remains interested, the time inconsistency appears again today.

It seems that fr24 is using the great circle distance to calculate the arrival time.

A quick check, assumng the a/c routes directly via the pole, the extra distance compared to the great circle is about 1000 nm (up longitude of Helsinki and down longitude of Tokyo).

However the actual track will be longer because the a/c cannot go down the longitude of Tokyo as it goes over Russia.

This, I suspect, accounts for the 4hr discrepency.

Aren't you all absolutely fascinated by this astonishing revelation.

[TheGreenGoblin]

If anyone remains interested, the time inconsistency appears again today.

It seems that fr24 is using the great circle distance to calculate the arrival time.

A quick check, assumng the a/c routes directly via the pole, the extra distance compared to the great circle is about 1000 nm (up longitude of Helsinki and down longitude of Tokyo).

However the actual track will be longer because the a/c cannot go down the longitude of Tokyo as it goes over Russia.

This, I suspect, accounts for the 4hr discrepency.

Aren't you all absolutely fascinated by this astonishing revelation.

It is interesting, and pretty poor software programming from FR24.

It was quire clear from the great circle tracker link, that I posted last night, that this was the case.

[Rwy in Sight]

If anyone remains interested, the time inconsistency appears again today.

It seems that fr24 is using the great circle distance to calculate the arrival time.

A quick check, assumng the a/c routes directly via the pole, the extra distance compared to the great circle is about 1000 nm (up longitude of Helsinki and down longitude of Tokyo).

However the actual track will be longer because the a/c cannot go down the longitude of Tokyo as it goes over Russia.

This, I suspect, accounts for the 4hr discrepency.

Aren't you all absolutely fascinated by this astonishing revelation.

Yes and to be honest it took me ages to understand the great circle distance and the advantage of overflying the polar areas on a long distance route between Europe and Asia.

[PHXPhlyer]

Only problem with polar areas is high radiation.

PP

[Undried Plum]

Teaching pilots how to do great circle nav on a polar grid is a bit of a challenge too!

[Undried Plum]

If anyone remains interested, the time inconsistency appears again today.

It seems that fr24 is using the great circle distance to calculate the arrival time.

A quick check, assuming the a/c routes directly via the pole, the extra distance compared to the great circle is about 1000 nm (up longitude of Helsinki and down longitude of Tokyo).

However the actual track will be longer because the a/c cannot go down the longitude of Tokyo as it goes over Russia.

This, I suspect, accounts for the 4hr discrepancy.

Aren't you all absolutely fascinated by this astonishing revelation.

It is interesting, and pretty poor software programming from FR24.

It was quite clear from the great circle tracker link, that I posted last night, that this was the case.

I think you are both right.

Compare the displayed flight time as shown on FR24 with that of FlightAware.

At the time of writing FR24 is showing a flight time for this evening's Finnair71 of 9 hrs 3 mins.

FlightAware is showing a much more realistic ETE of 13hrs. There, right there, you have the 4hr discrepancy.

I suspect that FlightAware is either taking the ETA from the ADSB squitter or else it's using the filed flight plan waypoints and speeds and known winds.

[Undried Plum]

I see that those flights are nowadays going South-about Russia instead of going the polar route. They now go through the 'stans to the Nor'ard of Afghanistan and then across China and South Korea.

Flight time of 13 hours seems to be about the same either way, so I guess the overland route gives a lot of options in the event of an en-route diversion. The Arctic Ocean route would mean an en-route div would involve landing in Russia where it can be presumed that the aircraft would immediately be impounded in retaliation for all those Russian-owned/leased aircraft which have been poggled as part of the economic warfare against the Russian people.