Why do the the direct SIN-JFK/EWR-SIN flights only go in one direction

[Matt_01]

Not a show stopping question but I am curious as to why SQ run the direct flights SIN-EWR/JFK-SIN (SQ 21/22 and SQ23/24) in one direction only heading east, I only noticed this the other day when looking at FR24. I have previously used SQ to get to/from the US landing in JFK and coming back the same way or into the West Coast via ICN or NRT. If SQ fly SIN-EWR/JFK in one direction why do they not come back the same way?

 

[MEL_Traveller]

Not a show stopping question but I am curious as to why SQ run the direct flights SIN-EWR/JFK-SIN (SQ 21/22 and SQ23/24) in one direction only heading east, I only noticed this the other day when looking at FR24. I have previously used SQ to get to/from the US landing in JFK and coming back the same way or into the West Coast via ICN or NRT. If SQ fly SIN-EWR/JFK in one direction why do they not come back the same way?

I think it might be tailwinds? Due to the length of the flight and it’s non-stop nature they can fly the direction with the greatest assistance.

 

[dajop]

Always more favourable travelling east (look at flight times between SIN and the east coast of Australia, or DRW-LHR) due to the meteorological conditions. SIN-NYC is far enough that it is favourable to continue around the globe to take advantage of this, even with the longer routing avoiding Russian airspace. Previously, sometimes NYC-SIN would take a polar route , sometimes it would track over Sweden (depending on conditions) but now it is a much more southerly route (a couple I looked at tracked over LHR/IST).

But consider the outbound route roughly via HND and compare to SIN-HND and HND-JFK flights. I picked some flights on same day on these routes, just to illustrate

SIN-HND 5:55, HND-JFK; 12:05, total 18 hrs flying time (this excludes taxi-ing but obviously includes take off, landing and ascent/descent)
JFK-HND 14:10, HND-SIN 6:45, total 20hrs 55 mins.

That's an extra 16% flying time! Compare to SIN-JFK 17:10 , JFK-SIN 18:30 (again random dates), only 8% extra flying time.

 

[Kiwi_Flyer]

It's to do with tailwinds, and compounded at the moment due to unable to overfly Russia.