V Australia LAX - Mel slower than QF

[NM]

Its not an accurate tool when you factor in the jetstreams that are experienced resulting in a ground speed less than 410kts single engine, keep in mind LAX-SYD is what is being discussed rather than SYD-LAX, and its the westbound route where you often get significant jetstream activity resulting in a much slower ground speeds. It is a good tool if you change the variables to reflect real world conditions rather than theory.

Why would direction of planned flight affect ETOPS? In the event of an engine failure, its about time to nearest suitable airport and that could be in any direction, not necessarily in the direction you were heading when you experienced the failure. So ETOPS constraints would be the same for SYD-LAX and for LAX-SYD.

And the "single engine speed" has to drop down to around 360knots before the 180 minute shading encroaches on the great circle routing.

 

[ButFli]

Yes I agree. This is the point I was making earlier about the great circle route not going through ETOPS 180 restricted airspace. The only difference in travel time should be due to different cruise speeds.

Of course the fastest route is not necessarily the shortest. I suppose the route that best takes advantage of / avoids the jetsteam could take aircraft far enough South that it goes through ETOPS 180 restricted airspace which would allow the QF 747s and A380s to complete the trip faster than VA 777s. But as I posted earlier, QF and VA take the same route. It's only Delta that flies significantly further North. If both aircraft are flying the same path you can't say the difference is due to ETOPS.

 

[oz_mark]

Qantas give a scheduled duration of 15h 35m, while V Aust have it at 15h 45m, so there is only 10 minutes in it.

 

[markis10]

Yes I agree. This is the point I was making earlier about the great circle route not going through ETOPS 180 restricted airspace. The only difference in travel time should be due to different cruise speeds.

Of course the fastest route is not necessarily the shortest. I suppose the route that best takes advantage of / avoids the jetsteam could take aircraft far enough South that it goes through ETOPS 180 restricted airspace which would allow the QF 747s and A380s to complete the trip faster than VA 777s. But as I posted earlier, QF and VA take the same route. It's only Delta that flies significantly further North. If both aircraft are flying the same path you can't say the difference is due to ETOPS.

ETOPS comes into play from time to time as JB747 mentioned, it all depends on the current headwinds and company policy/certification, for instance Delta is 30 minutes longer tonight than VA and QF (I have the feeling they run ETOPS 138).

You cannot say QF and VA take the same route all the time, heck its not unusual to see two QF birds on different routes just like they are tonight. The whole discussion is somewhat academic, no aircraft flys direct LAX-SYD via the great circle routing at the nominated engine out ground speed, even if they did fly direct at times they are looking at 300K single engine ground speeds for part of the flight during certain times of the year, have a look at the difference that makes.