V Australia LAX - Mel slower than QF

[whoistheg]

Just looking at the flights from LAX - Mel

and i notice

V-Australia VA 12

leave LAX at 21:40
Arrive MEL at 08:25

Qantas QF 94

Leave LAX at 23:20
Arrive MEL at 08:40

Does A Australia fly slower than QF?

 

[BAM1748]

Others here will know better than me, but perhaps because of 2 rather than 4 they need to fly closer to Hawaii than QF who use 4 engined planes and can cut straight across. (or trying to drive economically)

Matt

 

[Aussie_flyer]

Hmm, I have it leaving at 22.50. makes it a bit closer? They use different kinds of aircraft anyway...

22:50
Los Angeles
Tue 5 Oct
08:25
Melbourne
Thu 7 Oct
VA12

 

[MelUser]

Note some airlines build in more fat to make them look more on time.

I can remember when MEL-ADL was a 1 hour flight.

These days due to traffic congestion and whatever it is closer to 1 1/2 hours!

 

[whoistheg]

Sorry Guys

I should of added

Return date 7th Nov 2010

 

[markis10]

ETOPS may add some time to the trip, but more likely its creative timings.

 

[StevePER]

We used to have a theory that DJ fly slower than QF to save fuel.

 

[MelUser]

Back in the Ansett days, Qantas pilots were allowed to fly faster to make up for lost time if an aircraft was late in departing. This did result in extra fuel costs but those were less cost conscious (and save the planet) days compared to today.

 

[whoistheg]

ha.

I just looked at the QF94 (a380) depart LA on the Sun 7th Nov

and its departs 23:20 arrive mel 09:55 (15:53min)

the QF94 (747) which leaves on Sat 6th Nov QF94
23:20 arrive mel 08:40 (15:20min)


Im guessing QF website is pretty screwed with arrival times

 

[markis10]

ha.

I just looked at the QF94 (a380) depart LA on the Sun 7th Nov

and its departs 23:20 arrive mel 09:55 (15:53min)

the QF94 (747) which leaves on Sat 6th Nov QF94
23:20 arrive mel 08:40 (15:20min)


Im guessing QF website is pretty screwed with arrival times

The A380's do cruise at a higher mach rate than the 747s AFAIK, but I am sure our resident expert (JB747) will be able to provide the facts.

 

[straitman]

The A380's do cruise at a higher mach rate than the 747s AFAIK, but I am sure our resident expert (JB747) will be able to provide the facts.

That is a hard one to call as the published information is not really comparable.

The B744 has a typical cruise speed of M.85 and the A380 has a maximum cruise speed of M.89.
ie Boeing does not mention their max cruise speed and Airbus does not mention their typical cruise speed.

 

[mannej]

What date does DLS start over east?

I may be well off but it has played gremlins before has it not?

 

[oz_mark]

ha.

I just looked at the QF94 (a380) depart LA on the Sun 7th Nov

and its departs 23:20 arrive mel 09:55 (15:53min)

the QF94 (747) which leaves on Sat 6th Nov QF94
23:20 arrive mel 08:40 (15:20min)


Im guessing QF website is pretty screwed with arrival times

California daylight saving ends 2am Sunday 7 Nov.

 

[ButFli]

ETOPS may add some time to the trip, but more likely its creative timings.

There ain't be no ETOPS restricted airspace on the great circle route between LAX and MEL.

 

[markis10]

There ain't be no ETOPS restricted airspace on the great circle route between LAX and MEL.

ETOPs aircraft still need to meet their alternate requirements which are more rigid than the A380/B744 and this does affect track, have a look at tonights Va vs QF 744 plans LAX-SYD:

VA
PRCH9 DINTY R576 DUETS 3100N 13000W 2400N 14000W 1700N 15000W 1000N 16000W CEBUR 0500S 17700W 1000S 17800E 1500S 17300E PULON 2500S 16300E ABARB SHARK N774 SY

QF108
PRCH9 DINTY R576 DUETS 3300N 12500W 3000N 13200W 2500N 14000W 2100N 14500W 1800N 14900W 1300N 15600W 1100N 15800W 0500N 16500W 0100S 17100W 0500S 17539W 0700S 17800W 1300S 17500E 1700S 17000E 2000S 16600E 2227S 16300E 2400S 16100E 3000S 15600E 3151S 15415E MARLN N774 SY

 

[ButFli]

But I look at tonight's flight plans and QF and VA are virtually identical. The waypoints are different but as a line on a map they are virtually indistinguishable. If anything QF is further slightly North than VA. The VA flight is actually 3 minutes faster than QF. DL on the other is hand is flying significantly further North (over Hawaii) and is 2 minutes faster than VA. What's going on there? (not saying anything about the estimated flight times, just the flight paths)

I don't think the explaination is that VA have forgotten to fly an ETOPS compliant route.

 

[markis10]

But I look at tonight's flight plans and QF and VA are virtually identical. The waypoints are different but as a line on a map they are indistinguishable. The VA flight is actually 3 minutes faster than QF. DL on the other is hand is flying significantly further North (over Hawaii) and is 2 minutes faster than VA. What's going on there?

I don't think the explaination is that VA have forgotten to fly an ETOPS compliant route.

Not all aircraft and companies fly to the same ETOPS rules, or company policies with regard holding fuel etc. At the end of the day the timetabled intervals are a rough guide only, actual flight path, holding requirements and winds determine the true flight time. Sometimes the longer distance is the shorter flight

 

[jb747]

The planned (i.e. scheduled) times are based on whatever percentile the airline feels like using. The QF ones are 95%...meaning that the scheduled time will be only be less than the actual on about 5% of occasions.

If you go back a while to when Ansett and TAA existed, then they basically used to make up the timings out of thin air. Travel agents and passengers used to book with whichever mob claimed the fastest sector time, so they both had domestic sector timings that simply were not achievable. That wasn't too bad, but then they compounded the problem by having their turnarounds and next departures based on these fictitious timings, so that the aircraft would be late on the first sector of the day, and it would progressively get worse during the day. When QF bought TAA, and the 767 started doing some domestic flying, we were bemused to find that 737 sectors timings from Sydney to Melbourne were faster than could be flown on a 767. Eventually the stupid commercial or marketing people who make such decisions were pulled into line, real timings published, and the crews stopped roaring around at F280 and mach .85.

Crews can, and do, operate faster after delays, but there are numerous factors that affect whether they will choose to do so. On a domestic sector, the ability to make up time is extremely limited (767 would already be operating at .82, so there's only a small amount extra available, and might save you a minute or two). ATC also get into the act, as they rigidly control the sequencing, and gaining such a small margin is likely to simply mess that up. High speed, high drag, descents can also save time, but are very uncomfortable, and require cabin service to be stopped by ToD, as well as ATC compliance. Long haul, .01 mach over 12 hours will get you 10 or so minutes, but won't come for free (fuel wise), and in many cases will simply be thrown away by ATC. Basically it is very easy to lose time, but close to impossible to gain any appreciable amount back.

The 747 and the A380 cruise at about the same speed....mach .85 reducing to .83 (then climbing). The 747 max speed is .92, but it can't achieve that in level flight, though it will get to .91. That requires max continuous power, and is extremely thirsty. RVSM rules place a maximum speed of .90 on all aircraft, but again, it is never fuel efficient to get anywhere near that number. The A380 max is .89, but the system will limit you to 5 knots below that, which will equate to .88. Again, hugely thirsty. High speed for a short period of time can be used to make ATC requirements, where the alternative might be a reroute, or loss of preferred altitude, but those numbers will not be used routinely. I'm not 100% sure, but I think the 777 cruises around .02 slower, which would mean around 12 knots, and so would make any flight about 15 minutes longer than a 744 (using the same route and altitudes). On the other hand, even on the same route, it the 777 operates higher than the 747, that will cost it slightly more time (same applies to the 380).

The 777 will be affected by ETOPs on the Pacific if it is using 180 minutes, though 217 will get it across. Long way from anywhere though....

 

[NM]

The 777 will be affected by ETOPs on the Pacific if it is using 180 minutes, though 217 will get it across. Long way from anywhere though....

I understand this is not supposed to be an accurate tool, and many other factors come into play (such as prevailing/expected weather conditions), but this implies that a 777 can operate SYD-LAX without any route restrictions with ETOPS 180 unless the preferred routing is well south of the great circle routing.

 

[markis10]

I understand this is not supposed to be an accurate tool, and many other factors come into play (such as prevailing/expected weather conditions), but this implies that a 777 can operate SYD-LAX without any route restrictions with ETOPS 180 unless the preferred routing is well south of the great circle routing.

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.