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Kayro
Topic Author
Posts: 3
Joined: Sat Nov 07, 2020 10:36 am

Maximum tons of cargo for a B787-9 and B777F?

Sat Nov 07, 2020 10:49 am

Hello

I have two questions.

What is the maximum (structural) weight limit for the upper deck of a Boeing 777 freighter?

If you look here
https://www.anacargo.jp/en/int/specification/b7f.html

you can load up to 56,925kg into the lower deck.
So, let's assume the belly is completely empty or is filled with just 10t.

How many tons can you now load into the upper deck? 50, 70, 90 tons?


My second question is, how many tons of cargo fit into the belly of an Boeing 787-9?

I read somewhere here a B787-9 from UA weighs 124.5t without pax, food and fuel etc.
The plane right out of the factory with galleys and crew rest, but without seats weighs 117.5t. Is this correct?
So UA's interior weighs around 7t. Wikipedia says ca. 128,5t in general, but that would be even worse.

Because if you look here, this doesn't add up:
https://www.anacargo.jp/en/int/specific ... 787_9.html

Weight Limitation:
FWD 32,005kg
AFT 25,655kg
BULK 2,735kg

That is 60,395kg. That is a lot!

The MZFW of a 787-9 is 181,400kg. So 181,400kg minus 60,395kg
is 121,005kg. ANA's interior weighs just 3,5t? That can't be possible, right?

I hope you can help :)
 
WIederling
Posts: 10041
Joined: Sun Sep 13, 2015 2:15 pm

Re: Maximum tons of cargo for a B787-9 and B777F?

Sat Nov 07, 2020 12:33 pm

Nowhere is it written that you can max out all 3 locations simultaneously.
LIMITS:
At the top there is MTOW
below that is MZFW
below that is load positions ( moderated by balance requirements.)
 
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MoKa777
Posts: 1127
Joined: Fri Oct 21, 2016 11:47 am

Re: Maximum tons of cargo for a B787-9 and B777F?

Sat Nov 07, 2020 1:39 pm

For the B789, I believe the weight limitation information provided by ANA is based on the maximum structural load limitation of the lower deck cargo hold floor (floor limitations are also given as kg per square meter). This is what can theoretically be loaded in the cargo hold before reaching the structural limits of the floor and damaging the floor. It is not necessarily what an airline will load in the aircraft.

Some cargo may be low density but bulky (think a consignment of feather duvets), thereby taking up a lot of space in the cargo hold but not reaching (forget exceeding) the maximum floor load limit. Other cargo may be very dense but relatively small in size (think a consignment of gold bars), thereby reaching the floor load limit of the cargo hold before filling the volume of the cargo hold.

In aviation, it is always a give and take, respecting what you start with (the Basic Empty and Dry Operating Weights of the aircraft) and the upper limits - the maximum structural weights (MZFW, MTOW, MLW) or, as is very often the case, the restricted/performance-limited weights (RTOW, RLW).

There are also balance considerations (the other half of weight/mass and balance calculations and considerations) that would dictate loading a certain amount in the aft hold (or cabin) to balance/counteract the weight you may have already loaded into the forward hold (or cabin), for example.

The MZFW of a 787-9 is 181,400kg. So 181,400kg minus 60,395kg
is 121,005kg. ANA's interior weighs just 3,5t? That can't be possible, right?


Like I said, weight and balance considerations are a give and take within pre-existing limits. This makes things fun but complex.

The MZFW is one of the maximum limits. The Basic Empty Weight and the Dry Operating Weight of an airline's aircraft is also a relatively fixed number and where we may begin our calculations. We cannot simply subtract a "Maximum Weight of Loading" from the MZFW to arrive at a DOW for the aircraft. For example, the DOW for ANA's B789 could be 129,000kg (which is relatively fixed for a particular mission). With the given MZFW of 181,400kg, ANA can only load a maximum of 52,400kg into the aircraft (main deck AND lower deck).

181,400kg - 129,000kg = 52,400kg (I could be very wrong about the DOW of ANA B789 but I am just using this figure as an example)

How the airline chooses to split the load is up to the requirements of the day. There could be 20,000kg of passengers and hand luggage on the main deck leaving 32,400kg of weight that may be loaded into the lower deck cargo/bulk holds.

The above scenario does not factor in the conditions on the day that may restrict the TOW and/or LW of the aircraft. It also does not factor in the amount of fuel that will be required for the mission of the day and how that will limit the ZFW in order to remain within the Maximum or Restricted TOW/LW limits.

Complex but fun!

Likewise, the same considerations will apply to the B77F. The aircraft will have an existing DOW (mission specific) and maximum or restricted upper limits. The operational control personnel will have to play around with the rest of the numbers to find the best fit that SAFELY allows the airline to carry the highest payload to maximise revenue.
 
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zeke
Posts: 16744
Joined: Thu Dec 14, 2006 1:42 pm

Re: Maximum tons of cargo for a B787-9 and B777F?

Sat Nov 07, 2020 3:37 pm

Kayro wrote:
How many tons can you now load into the upper deck? 50, 70, 90 tons?


The upper deck has 4 zones, maximum load in each zone (from front to back) is 41149kg, 48487kg, 40010kg, 3543kg.

However other limits still have to be respected, so these zone limits are more academic than practical.

Kayro wrote:
My second question is, how many tons of cargo fit into the belly of an Boeing 787-9?


The MZFW of a 787-9 is 181,400kg. So 181,400kg minus 60,395kg
is 121,005kg. ANA's interior weighs just 3,5t? That can't be possible, right?

I hope you can help :)


This again is the same concept as the earlier part, the loading of a particular zone still needs to respect the overall MZFW limits, that means the hold limits are academic, they can never be reached as MZFW is reached first.
 
jayunited
Posts: 3607
Joined: Sat Jan 05, 2013 12:03 am

Re: Maximum tons of cargo for a B787-9 and B777F?

Sat Nov 07, 2020 4:06 pm

Also another thing I found fascinating is the correlation in UA's case between the passenger cabin zones and the cargo zones.

One aircraft in particular where this has become clear over the past few years is our 763s. In the old IPTE configuration UA could load three 9,000LBS pallets in the forward cargo hold. Once UA installed the BE Diamond seats which were heavier than the IPTE seats the number of 9,000LBS pallets dropped to two. With the Polaris seats which are extremely heavy the number drops to one and that pallet has to be loaded in the position nearest the bulkhead near the wing box. On our 763s with Polaris the pallet loaded in 11L (the nose right behind the nose gear) now has a max weight limit of around 4,500LBS, where as when we had IPTE configuration we could load a 7,000LBS pallet in position 11L.

The 777 and 787s are a bit more forgiving than the 763s but you still loose weight down below with those heavy Polaris seats, it just not as drastic as the 763. But what this shows is each zone on the aircraft has a total weight limit for both the main deck and lower cargo deck combined. The more weight you have allocated to the main deck mean there will be less weight available on the lower deck. Another thing people have to keep in mind is the further away you are from the center of gravity the less weight you can have in that zone. Lastly in all my years here at UA I have never seen UA come close to maxing out a cargo compartment weight wise because there are so many other factors in place like as others have pointed out MTOG, MZFW, and balancing out the aircraft.
 
JayinKitsap
Posts: 2752
Joined: Sat Nov 26, 2005 9:55 am

Re: Maximum tons of cargo for a B787-9 and B777F?

Sun Nov 08, 2020 12:41 am

Each zone has limits, based on the rated loading of the floor beams below it, but also each load unit x distance from the optimum CG comes into play. There are maximum forward and maximum rear positions for the CG. with trimming minimal at the optimum CG. As noted above, the heaviest pallets need to be closest to the wing box.

A good example would be a C-17 carrying a single tank. Probably needs to be located at optimum +- a foot or so to be in balance. If that tank broke loose and slid forward 5 feet it would be "Dive! Dive! Dive!" Too far back it would be Wheelee time. Needless to say either may have bad results.
 
Sokes
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Re: Maximum tons of cargo for a B787-9 and B777F?

Sun Nov 08, 2020 11:20 am

JayinKitsap wrote:
Each zone has limits, based on the rated loading of the floor beams below it, but also each load unit x distance from the optimum CG comes into play.

Video of cargo B747 crash in Afghanistan, I believe center of gravity shifted during flight.
https://youtu.be/ColjRb3gHrk
 
B777LRF
Posts: 2950
Joined: Sun Nov 02, 2008 4:23 am

Re: Maximum tons of cargo for a B787-9 and B777F?

Sun Nov 08, 2020 11:38 am

For practical purposes, the maximum lower-deck load on a 777F is around 50 tons. The maximum total payload is around 104 tons. You can load all 104 tons on the main-deck, which obviously would leave the lower-deck holds empty. Conversely, if you load 50 tons downstairs you're limited to around 54 tons upstairs. And any number of combinations in between, respecting a range of limitations such as:

Area load (maximum load in a given area, usually a ULD position)
Zone load (maximum load for a number of adjacent positions)
Linear load (maximum load per running meter)
Cumulative load (maximum upper- and lower-deck in the same vertical zone)
Asymmetrical load (maximum load of two positions side-by-side)

Much more to it than just MZFW, MTOW and MLAW.

Oh, and as for "brochure" weights published by an airline. Bear in mind these are published by the sales and marketing departments. Once the rubber meets the road and operations gets involved, the answer is always "it depends". I've given that answer more times than I care to remember, with subsequent attempts to educate the marketing people. Have always been met with a blank stare and the question "yeah, but what's the maximum". After a while you just resign, knowing that the people who really need to know, know better, and those who don't and consume these figures are usually sat in row 54 or lurking in an obscure corner of the internet, such as this one.
 
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SAAFNAV
Posts: 638
Joined: Wed Mar 17, 2010 5:41 pm

Re: Maximum tons of cargo for a B787-9 and B777F?

Mon Nov 09, 2020 6:01 am

Sokes wrote:
JayinKitsap wrote:
Each zone has limits, based on the rated loading of the floor beams below it, but also each load unit x distance from the optimum CG comes into play.

Video of cargo B747 crash in Afghanistan, I believe center of gravity shifted during flight.
https://youtu.be/ColjRb3gHrk


Yes, the center of gravity did shift, but simulations have shown that it alone would not have caused the aircraft to lose control.
What did seal their fate was that the vehicles broke through the pressure bulkhead and and severed the hydraulic lines to the elevator.
 
gloom
Posts: 593
Joined: Thu Jun 30, 2016 4:24 pm

Re: Maximum tons of cargo for a B787-9 and B777F?

Mon Nov 09, 2020 8:52 pm

SAAFNAV wrote:
What did seal their fate was that the vehicles broke through the pressure bulkhead and and severed the hydraulic lines to the elevator.


That's what I've heard as well.

However, there was (as far as I can remember) a disaster where a plane flipped due to load movement. The weird part is it was passenger plane. I seem to remember a fire (or smoke) that made the passengers go away from fire, and as a result of fire runaway, finally plane became uncotrollable.

Anyone knows the story? My memory's ringing the bells, but no details at all.

Cheers,
Adam
 
Max Q
Posts: 9147
Joined: Wed May 09, 2001 12:40 pm

Re: Maximum tons of cargo for a B787-9 and B777F?

Mon Nov 09, 2020 11:46 pm

SAAFNAV wrote:
Sokes wrote:
JayinKitsap wrote:
Each zone has limits, based on the rated loading of the floor beams below it, but also each load unit x distance from the optimum CG comes into play.

Video of cargo B747 crash in Afghanistan, I believe center of gravity shifted during flight.
https://youtu.be/ColjRb3gHrk


Yes, the center of gravity did shift, but simulations have shown that it alone would not have caused the aircraft to lose control.
What did seal their fate was that the vehicles broke through the pressure bulkhead and and severed the hydraulic lines to the elevator.




IIRC in that accident the vehicle, after breaking through the rear pressure bulkhead
severely damaged and jammed the horizontal stabilizer jackscrew, it remained in a position that provided a nose up force that could not be overridden by the less powerful elevators
 
Max Q
Posts: 9147
Joined: Wed May 09, 2001 12:40 pm

Re: Maximum tons of cargo for a B787-9 and B777F?

Mon Nov 09, 2020 11:48 pm

Kayro wrote:
Hello

I have two questions.

What is the maximum (structural) weight limit for the upper deck of a Boeing 777 freighter?

If you look here
https://www.anacargo.jp/en/int/specification/b7f.html

you can load up to 56,925kg into the lower deck.
So, let's assume the belly is completely empty or is filled with just 10t.

How many tons can you now load into the upper deck? 50, 70, 90 tons?


My second question is, how many tons of cargo fit into the belly of an Boeing 787-9?

I read somewhere here a B787-9 from UA weighs 124.5t without pax, food and fuel etc.
The plane right out of the factory with galleys and crew rest, but without seats weighs 117.5t. Is this correct?
So UA's interior weighs around 7t. Wikipedia says ca. 128,5t in general, but that would be even worse.

Because if you look here, this doesn't add up:
https://www.anacargo.jp/en/int/specific ... 787_9.html

Weight Limitation:
FWD 32,005kg
AFT 25,655kg
BULK 2,735kg

That is 60,395kg. That is a lot!

The MZFW of a 787-9 is 181,400kg. So 181,400kg minus 60,395kg
is 121,005kg. ANA's interior weighs just 3,5t? That can't be possible, right?

I hope you can help :)



Just a minor point

The 777 doesn’t have an ‘upper deck’
it has a main deck and a cargo hold

The 747 and A380 are two examples of aircraft with an upper deck !

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