SCAT15F From United States of America, joined Feb 2007, 402 posts, RR: 0 Posted (3 years 6 days 22 hours ago) and read 25524 times:
I can't believe no one has commented on this yet...
Boeing's December 2012 airport planning guide update shows a 15,300 lb increase in OEW to 485,300 lb and a range with 467 pax and baggage reduced to just over 7500nm; and this is WITH the MTOW increase to 987,000 lb.
(remember we were told that 5000 lbs of weight was just removed this past year with 5000 more on the way for 2014)
Original OEW was to be 471,000 lb (and change), and was reduced in the Dec. 2011 planning guide to 470,000 lb.
(OEW for the -8f is increased by the same amount, with range dropping to ~4250 and payload to 292,000 lb at the 987k MTOW)
Something is VERY wrong here!
I will admit I am one of the biggest 747-8i fanboy's of them all, but if this is true, it destroys the business case for this aircraft.
SCAT15F From United States of America, joined Feb 2007, 402 posts, RR: 0
Reply 4, posted (3 years 6 days 22 hours ago) and read 25085 times:
That is what is so puzzling... Lufthansa says it is actually getting 1% better fuel burn than expected, given the GEnx-2b fuel consumption shortfall... what were they basing their expectations on in terms of OEW?
Roseflyer From United States of America, joined Feb 2004, 10926 posts, RR: 52
Reply 5, posted (3 years 6 days 21 hours ago) and read 24969 times:
Quoting Aesma (Reply 3): We're learning this now but it has been there all along (or current flying planes are even heavier), right ?
The airport planning guide is generic and does not reflect actual airline configurations. It's a good starting point, but it isn't exactly what the real numbers are. Weight and balance procedures are provided in FAA Advisory Circular (AC) 120-27. There's a weight and balance program for every airline based on their airplane configuration.
5,000lbs is a big deal as far as fuel burn goes, and this might help explain the popularity of the airplane, however comparing different models exclusively on the airport planning guide results in a lot of assumptions and inaccuracies that can skew the results. Airlines know this.
If you have never designed an airplane part before, let the real designers do the work!
Stitch From United States of America, joined Jul 2005, 33659 posts, RR: 85
Reply 10, posted (3 years 6 days 18 hours ago) and read 23484 times:
Quoting SCAT15F (Reply 8): Also, going from 466,700 to 485,300 is just incredible, and rather disappointing.
Those earlier figures would have been projections since the 747-8 was still in the design stage.
The December 2012 figure could also represent the OEW of the first frames, which would have the full 10,000 pounds of overage. For a time, Boeing listed the 787-8 OEW based on the Block Point when it would be at spec weight. When that Block Point shifted to later frames, Boeing revised the OEW upwards to reflect the current Block Point OEW. So a "fully optimized" 747-8 might have an OEW of 475,000 pounds - close to the January 2008 OEW.
kanban From United States of America, joined Jan 2008, 4253 posts, RR: 30
Reply 11, posted (3 years 6 days 17 hours ago) and read 22388 times:
One think to look is the purpose of the document... airport planning So it should show the maximums of the earliest members of the fleet since you never know which aircraft will arrive. Say you took the most recent and allowed no insurance then the heaviest arrived and sank through the asphalt...
Thanks for that explanation, that makes a lot more sense. So for 2014 we have a 475,000 lb OEW with the GEnx-2b performing at or slightly better than spec, plus the trim drag reduction that comes with an activated tail fuel tank, and range might increase to 8100-8200 nm.
Of course Boeing still has room to increase MTOW as well, I would guess to at least 1,000,000 pounds based on testing to 1,010,000 pounds.
Either way, the 4% thrust bump for the freighter should become standard given that thrust has stayed the same from the start of the program (66,500 lb) while the aircraft was lengthened and MTOW rose from 960,000 lbs to 987,000 lbs.
I think that LH means that it's 1% better than boeing revised specs that should include the real weights... Theses revised specs can be less than projected specs at the beginning of the program... (or the same if it's a well run program )
Also, specs or garantees written in sales contract can be less than projected specs
seahawk From Germany, joined May 2005, 2673 posts, RR: 1
Reply 15, posted (3 years 6 days 13 hours ago) and read 18708 times:
LH must have made s splendid deak with Boeing. LH seems happy with the 747-8 although all data shows that they should not be happy. I wonder how many performance clauses were not meht and how much discount LH could get becuase of that. I would not be surprised if they got those 747-8i for less money than they would have had to spent on a regular 77W order.
TC957 From UK - England, joined May 2012, 1814 posts, RR: 0
Reply 18, posted (3 years 6 days 11 hours ago) and read 16748 times:
Wonder if this will influence CX's much-debated decision on a potential 748i / A380 VLA purchase since it looks like one key route like HKG - JFK won't be doable with a 748i now but should be with post-2015 A380's ??
ferpe From France, joined Nov 2010, 2807 posts, RR: 60
Reply 19, posted (3 years 6 days 11 hours ago) and read 16376 times:
Quoting TC957 (Reply 18): it looks like one key route like HKG - JFK won't be doable with a 748i now but should be with post-2015 A380's
The A380 is further along in it's maturity, it started with the same problems as the 748, if you need the frame to fly very long legs in the near vicinity in time this can affect your decision, if it is a decision for the long term the frames true mature potential will decide. I expect the 748 to get back to spec 8000nm just like the A380 did (it has now passed it).
Another thing to have in mind is that the 748 spec pax count is done with an old spec seating standard, more so then the A380. If you load both to the same standard the 748 will have less seats and pax, ie it will be taking more fuel and flying longer. Say the diff is 40 seats, the seat+pax+bags weigh some 6t. Take it away with an average FF of 10.6t per hour this gives you an equalized 748 spec range of 8000nm, the same as the present A380 (the Dec 2012 ACAP spec range is ~ 7700nm not 7500).
I think you can say for equal maturity they have equal range if you seat the 748 and the A380 to the same standard.
airbazar From United States of America, joined Sep 2003, 9702 posts, RR: 10
Reply 20, posted (3 years 6 days 9 hours ago) and read 14967 times:
Quoting ferpe (Reply 19): The A380 is further along in it's maturity, it started with the same problems as the 748
The A380 was a brand new, clean sheet airplane. The 748i is a new version of a 40 year old airplane. The 748i is a far more mature platform than the A380 will ever be, IMO. So that excuse doesn't fly with me. The whole point of the 748i was that it was a very low risk and low cost (for Boeing), airplane. But if Boeing is having to give it away because it can't meet its contractual obligations (not a fact, just a plausible sugestion), then something would be seriously wrong.
KC135TopBoom From United States of America, joined Jan 2005, 12336 posts, RR: 51
Reply 21, posted (3 years 6 days 9 hours ago) and read 14911 times:
Quoting TC957 (Reply 18): Wonder if this will influence CX's much-debated decision on a potential 748i / A380 VLA purchase since it looks like one key route like HKG - JFK won't be doable with a 748i now but should be with post-2015 A380's ??
According to GCM, the HKG-JFK route is 7014 nm, well inside the B-747-8i range now.
Quoting ferpe (Reply 19): The A380 is further along in it's maturity, it started with the same problems as the 748, if you need the frame to fly very long legs in the near vicinity in time this can affect your decision, if it is a decision for the long term the frames true mature potential will decide. I expect the 748 to get back to spec 8000nm just like the A380 did
sunrisevalley From Canada, joined Jul 2004, 5888 posts, RR: 6
Reply 22, posted (3 years 6 days 9 hours ago) and read 14235 times:
Quoting TC957 (Reply 18): one key route like HKG - JFK won't be doable with a 748i now but should be with post-2015 A380's ??
Quoting KC135TopBoom (Reply 21): According to GCM, the HKG-JFK route is 7014 nm, well inside the B-747-8i range now.
JFK-HKG is a 16hr flight which gives it an ESAD of ~ 7500nm. The ZFW for this distance from the Dec.2012 load/range chart is ~265t. With OEW at ~220t this gives a 45t payload. or about max passenger load based on Boeings 3-class standard layout.
airlinebuilder From Philippines, joined Nov 2012, 203 posts, RR: 0
Reply 23, posted (3 years 6 days 9 hours ago) and read 13955 times:
I think we should all sign a paper of consent on DNR (do not resuscitate) so to speak, lets give the B748i a rest.....its one of those aircraft that has served its time. Lets just let her be the aircraft that could have and would have but did not really happen.......