Hong Kong - JFK - Is this right?

http://flightaware.com/live/flight/CPA840/history/20121021/0810Z/VHHH/KJFK

Almost 20 hours - non-polar route, is that real? There is 3 other flights like that the previous 7 days.

That's something like 4-5 hours longer than the normal plan.

If that is correct, what would be the reason for flying like that?

 

Because it basically flew due east instead of up and over near the north pole, which is shorter but windy thanks to Hurricane Sandy.

 

Correction: not because of Sandy. Flight was on October 21.

Below is the due east path compared to the north pole route.

Mercator projection makes the latter look longer.

I have no idea why they flew that way.
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They wanted to see beautiful downtown Vancouver?





I have no idea... the East route is MUCH longer... unless there were, in fact, severe headwinds over the pole route.

 

I looked up the range of the 777-300ER and it is 7930 nautical miles or 9120 statute miles. I'm not sure how this is changed by route specific and airline specific reserve fuel requirements.

The direct route is 8068 statute miles and the longer route is 9300 to 9400 statute miles, according to Flight Aware. So the route is near or beyond the limits of the aircraft, winds not considered. If you look at the Flight Aware route log, it shows that it took the long route Oct 18, 19, 21 and 22, but the short route otherwise.

However, if the direct route has insufficient tailwinds or excessive headwinds, while the long route has good tailwinds, then it could be preferred (or even required, due to fuel reserve issues). The jetstream chart below for 10K meters (33,000 feet) shows that tailwinds of 100-200 knots are possible across the pacific route. I've often been on Asia-West Coast flights that arrived 1-2 hours early.

http://www.stormsurfing.com/cgi/display_alt.cgi?a=npac_250

The airline pros will probably give a much better answer.

 

I would be willing to bet that it was the winds.

 

I figured it has something to do with wind speed - but still couldn't understand it. The polar route would have had worse winds? As it was, it took nearly 20 hours, 4-5 hours longer than normal.

Maybe something to do with ETOPS because of the winds on the polar route?

 

Yeh, ETOPS would probably be right. Probably an airport used for ETOPS on that polar route was closed or unusable. That forced them to flight plan further south to maintain the 180 mins ETOPS requirement.

One of the few times a 4 engine airplane would have saved fuel....

 

Thanks! Interesting.

I wonder if it stopped in Anchorage? Usually flightaware will show the stop (flight split into two), so maybe not. But here are the waypoints mapped out...

http://skyvector.com/?ll=54.724620197292346,-153.93164062600934&chart=301&zoom=13&plan=F.PA.PASRO:F.PA.PUGGY:F.PA.HAMND:F.PA.AMOTT:V.PA.TED:F.PA.YESKA:F.CY.PETMA:V.CY.YRL:V.CY.YYZ:F.K6.KLOPS:V.K6.ROC:V.K6.IGN

 

According to that link, it must have stopped in Anchorage. There wouldn't be a "break" like that after ANC. And YESKA is on the arrival and departure for Anchorage. It's not a waypoint used enroute.

The airport normally used for the polar route either had bad weather, or the runway was closed. I don't fly that route (polar), but I do fly into Anchorage on a normal basis. I'm not sure what ETOPS airport is used, but up that way there's probably only one. If I had a chart handy, I could probably find it. Again, I don't fly an ETOPS airplane nor have I ever, but you basically get a chart and draw "3hr circles" around suitable and usable airports along the route. The ETOPS airplane has to be within those circles at all times. A 3 hr circle with no wind would have about a1400 mile radius for a 777.

I'm guessing the total time of 19 or 20 hours included the 1 hour refuel Anchorage stop.

One other point....I'm assuming those were passenger aircraft. Cargo aircraft would typically plan an Anchorage stop. This is because cargo aircraft carry more of a load in the fuselage and can't carry enough fuel to go nonstop. For a 747-400, if it carried 500 passengers at say 200lbs apiece, that's 100,000lbs. A 747-400 cargo plane can carry around 250,000lbs. So you lose the extra 150,000lbs of fuel.

Another interesting point, because of what I mentioned above, cargo aircraft typically land near MaxGross Landing Weight. Passenger aircraft never come close to it. So a cargo 747 would have a noticeably higher approach speed than a passenger plane.

Just some useless trivia.......

 

Awesome, it makes total sense now - when you include the time for the stop.

Cut and pasting the waypoints from flightaware into SkyVector is pretty cool - something I haven't done before - but certainly helps explain everything you are looking at.

Thanks for the input!

 

I've never seen that program before. Looks very useful....

 

Did you look at the FlightAware that BubblesQuah posted????

The plane didn't go anywhere near Anchorage.

What is that based on?????

 

I actually didn't look at it. I looked at the Skyvector site showing YESKA as a fix. If YESKA was a fix, I'd say 99% it landed in ANC. Now looking at the original flight plan for Cathay 840, I see that flight didn't go near ANC.

Either way, I'm guessing a required airport for ETOPS was either closed or unsuitable and that's why the plane was on such a long route.

There's a guy on here, LSeven, or something like that. I believe he flies a 777 for Cathay and would be able to give an easy answer.

 

Sorry for the confusion.

The flight plan I mapped above on sky vector was from one of the other 20 hour versions of CPA840, not the one I posted at the beginning of the thread above.