Okay, I just finished watching "Moana" and I'm really in far too good of a mood to keep arguing this. Plus I know from past experience the moderators are going to wade in here soon enough if we keep doing it and closing the thread for veering seriously off-topic. So this is my last post on the matter.
If you don't like what I post, zeke
, feel free to flag it to the Moderators with your reasons. If they agree with your view that it is a low-quality post, they'll delete it as such and send me a nastygram.
Stitch, your above 777-300ER claim of carrying 70T of payload over 5750nmi is only correct under the following very specific assumptions...The truth is virtually none of those assumptions are used by airlines. Each airline has it's own assumptions for product & resulting OEW, "standard day" & winds aloft, and mission rule-sets/reserves. Any deviation from Boeing's assumptions will result in reducing the payload/range of the airplane.
100% in full agreement with you, heavymetal
. I am fully aware the ACAPs numbers are not representative of real-world airline planning and I therefore did not present them as such. By noting they were numbers from the ACAP, I had hoped to make it clear that said numbers would take into account those caveats because in the past I have agreed with zeke
, other pilots and fleet planning professionals at airlines who have posted on this site the same things you did above about how real airlines plan real flight plans and they don't reference the ACAP's payload-range charts when they do it.
But if I just put numbers out there on their own, someone is going to demand I note where they're from. Or they'll accuse me of just randomly making stuff up or selectively quoting some OEM PowerPoint marketing slide to try and smear one OEM or promote another. The ACAPs are something the general public can quickly and easily acquire to confirm or deny the numbers themselves. That the Payload-Range charts within them are not accurate representations of real-world performance is important, but considering how much has been said about that topic in these forums, I presumed that the general audience here understands that and takes it into consideration and does not consider them "absolute truths".
One simply cannot load 70 tonnes of payload onto a 77W, and as you know Boeing has revisited its performance assumptions to make them more realistic. I dont believe the "layman" tag for a second, you are versed enough to run the numbers for the 77W, you just did not know, or chose to ignore what the number means.
they have. But not in the two sections I quoted. The original chart was from April 2009 (as that was the last update) and just to be sure, I downloaded the latest version which is now March 2015. As I indicated in the original thread, the numbers for Section 2.1.1 (General Characteristics) and the chart on Section 3.2.2. (Payload/Range for 0.84 Mach Cruise: Model 777-300ER) are exactly the same as the ones I posted. If they were different, I would have admitted as such just as I have done in the past when presented with updated evidence. And if Boeing is using different, higher numbers in other documents, then I agree with you that they should be using it in their ACAPs, as well. But they haven't, as of yet, so I am using the numbers provided in the ACAP. When they revise them, I shall be sure to note that.
And yes, no airline will be able to load 70,000kg of payload into one of their 777-300ERs because the DOW / DOM would be a fair bit higher than the 168,000kg (rounded up) Boeing OEM figure (and yes, I know DOW / DOM includes more items the OEW, which is why an airliner's actual DOW is always higher than an OEM's OEW) so you'd reach he rated MZFW before you reached rated Maximum Structural Payload. But if you had a 777-300ER with a DOW / DOM of 168,000kg (rounded up) loaded with 70,000kg of something that would fit inside it with the proper weight and balance and then filled up with fuel to Maximum Taxi Weight and sent off to the runway on a "Standard Day" with the assumptions Boeing makes on winds and step climbs and power extraction and mission rules, you might very well get to around 5750nm before you had to strap on your parachute and bail out (depending on what assumptions Boeing made on reserve and alternate field fuel).
And no, I do not consider myself a "layman" in the general sense of the term. But as you have pointed out, I am not an ATP certified to fly any Airbus or Boeing Commercial Airliner. Nor did I ever serve as an Airline Route Planner or Fleet Operations Manager. And I do not have access to the tools used by those professions to develop flight plans, evaluate airframes or perform mission planning. If I did, I'd certainly use them where allowed. And yes, I could download PIANO-X, but because it is not as refined as the software airline pilots and planners use, it has been criticized by you for it's accuracy so to be honest even if I went through the trouble, you'd probably call me out on it, as well.
I gave you an opportunity when I responded to your post to indicate that you could have been unsure of your facts, instead you went on a pedestal and tried to make fun at my expense.
If you had commented that the ACAP data is not representative of real-world airline planning and therefore the numbers it presented were not, as well, my post would have been, as it has been in the past on this subject, one of 100% agreement with you. But instead you did your usual "he's lying to make Boeing look better and Airbus look worse because he's an evil fanboy with an evil agenda" routine. So I posted the charts to explain how I viewed the data they presented in an effort to explain that your interpretation was an incorrect one.
You are not a "layman", you have stated numerous times in the past to add credibility to your posts that you are former Boeing employee.
Not to add credibility, but to clarify my background, which was as a CATIA design engineer in the Structures team on Sonic Cruiser. Which is why I only ever brought it up on threads about Sonic Cruiser and we haven't had one of those for awhile.
Last edited by Stitch
on Tue Mar 14, 2017 8:52 pm, edited 3 times in total.