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-   -   Qantas PER-LHR and United's LAX-SIN on the 787-9, Technical considerations? (https://www.pprune.org/australia-new-zealand-pacific/597222-qantas-per-lhr-uniteds-lax-sin-787-9-technical-considerations.html)

swap1997 18th Jul 2017 14:24

Qantas PER-LHR and United's LAX-SIN on the 787-9, Technical considerations?
 
Hello everyone,

I was always in a quandary in how do Qantas and United plan on achieving their flight's feasiblility considering that the GC distance on both destinations exceeds 14000kms which is on the knife edge on the 787-9's range. Now, according to Boeing a 787-9 with a 254t MTOW can do 14635kms, but I had a doubt as to whether this includes winds aloft, payload considerations and fuel reserves? Am I missing something on this topic? Is there some way through which both of those flights are technically made feasible for the 787-9 to achieve some extra range or flight time?

Roj approved 19th Jul 2017 07:40

Sacrifice payload for fuel and hope the winds are in your favour :p

Ken Borough 19th Jul 2017 08:11

I think Boeing assumes still air and a full alternate. OTOH, Qantas' planning process does not assume the carriage of alternate fuel while the track winds can often be far more favourable than GC winds. For planning, I think an 85% adverse wind is assumed which means that on 85% of occasions, the actual winds will be less than those assumed in the planning practice.

Does this make sense? It's quite a complex process that's not readily known by most! :ok:

Roj approved 19th Jul 2017 08:24

I've heard 4.4 tonnes on arrival, therefore 96.6 tonnes available to burn

Transition Layer 19th Jul 2017 12:54

4.4T? That's pretty comfortable...in a 737

B772 19th Jul 2017 13:11

ROJ.

You are on the money with both comments. I understand QF restrict the A380 take-off weight from DFW so they can get to SYD nonstop. This has the effect of increasing the ground miles per kg of fuel in layman terms. I understand QF accept they will rarely get a MTOW from PER to LHR especially during Winter.

Roj approved 19th Jul 2017 15:33

And won't get anywhere near it on a 42 degree day in summer in Perth when LHR is Cat 3B

maggot 19th Jul 2017 22:07


Originally Posted by Roj approved (Post 9835816)
And won't get anywhere near it on a 42 degree day in summer in Perth when LHR is Cat 3B

*lots of close in alt, compared to aus
*early morning arrival (pre 6am) = bugger all traffic
*evening departure = doctor and probably not 42° (although I'd almost bet you could get mtow off per in 42°)

Keg 20th Jul 2017 02:23


Originally Posted by Transition Layer (Post 9835660)
4.4T? That's pretty comfortable...in a 737

It'll be a pretty light 787 so suspect 4.4 tonne will be 30ish minutes on top of FFR of 30 min and approach and landing.

Still, skinny!

The issue is if they're delayed- say by an hour. That pushes them back into the pack for holding of 20+ minutes as well as on the cusp of 20 hour tour of duty. Suspect lots of stuff happening behind the scene in order to address these sorts of problems.

CurtainTwitcher 20th Jul 2017 03:59


That pushes them back into the pack for holding of 20+ minutes as well as on the cusp of 20 hour tour of duty. Suspect lots of stuff happening behind the scene in order to address these sorts of problems.
The question has to be asked, why? Why make flying to LHR such a marginal operation? The vast bulk of the passengers flying on this will be doing 1 stop to London, except PER locals. There is no time saving that I can see, there is no ability to connect to other European destinations 1 stop.

Off the top of my head I can think of at least a dozen ways to get 1 stop to London. It isn't something special. If other operators making their operation as marginal as the 787, it is because they are packing the punters to the rafters, and have the ability to finesse payload vs fuel and have crew duty buffers.

It seems like an incredibly marginal operation to provide an already well serviced route via Asia or the Middle East. There appears to be almost no margin for error, with delay or diversion becoming an operational nightmare. Just about everything has to go right every day, why do it? The real world just doesn't work that way. Competing operators don't have the same self imposed limitations.

Keg 20th Jul 2017 05:11

Maybe they'll find 230ish pax per day to/from PER- to LHR. Perhaps people will like the stop over in PER instead of Asia if going to/ from LHR.

Many of the comments being made were once made about SYD- LAX as well. Then when MEL- LAX kicked off there were similar points made.

I hope they make a go of it. Perhaps we'll find within a couple of years that PER- direct to a bunch of places in Europe will become the preferred model for people travelling.

bangbounceboeing 20th Jul 2017 05:13

Last time I was in Perth on the B787-9 we couldn't get out of there at MTOW on runway 21 with nil wind and 34 degrees. The B787-9 doesn't perform all that well when the temp starts getting past 30.

t_cas 20th Jul 2017 05:15

Why do it?

PR simple. The biggest, the best, the longest, the fastest.... QF are trying to compete in the game of perception.

It is not about sense or operational certainty.

maggot 20th Jul 2017 06:48


Originally Posted by bangbounceboeing (Post 9836341)
Last time I was in Perth on the B787-9 we couldn't get out of there at MTOW on runway 21 with nil wind and 34 degrees. The B787-9 doesn't perform all that well when the temp starts getting past 30.

Thanks for the informed comment :)
Typical boeing dog eh

Although that does actually surprise me; are there different engine ratings available?

megan 20th Jul 2017 06:53

I look at it in the same way I experienced on the west coast US to Oz non stops in the early days. Some times you made it, and on occasions a stop in Nadi to top up. Prefer direct to where I'm going if available. Full marks to QF if it works.

maggot 20th Jul 2017 06:56

It'll make it fine way more often than not. Qf are well skilled in the balancing act ex DFW in that regard.
Whether 60 (?) J class can be filled daily and a sardine can are appealing is more my concern

WingNut60 20th Jul 2017 09:56

I also can not see the advantage for anyone, except Q, in this operation.
Sydney - LHR with a half way stop seems more appealing to me, if in cattle class, than 4 hours to PER then a loooooong flight to London.
One point to consider, is that this proposal was used by Q as a very long lever to get international operations running out of "their" terminal.
Thin end of the wedge ?????

Roger Greendeck 21st Jul 2017 07:15

Will the new 777 be able to go PER LHR direct? Maybe they test the waters and then get an aircraft capable of doing the flight more consistently in the future.

haughtney1 21st Jul 2017 16:39


Originally Posted by Roger Greendeck (Post 9837410)
Will the new 777 be able to go PER LHR direct? Maybe they test the waters and then get an aircraft capable of doing the flight more consistently in the future.

The 200LR can do it today without breaking a sweat, the question is could you make money? and of course QF don't have any of those airframes.

rog747 21st Jul 2017 18:01

they dont make the 777-200 anymore do they?


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