UPS Pilot From United States of America, joined May 1999, 867 posts, RR: 3 Posted (7 years 11 months 2 weeks 6 days 15 hours ago) and read 3855 times:
I was looking at a 777F sales ad today. The Main deck cargo door is behind the wing rather in front. Nobody could answer why? The only freighter by Boeing, Airbus or MDD/Douglas to date is the 747. Thats because of the upper deck. I thought it would be weight distribution while loading. We have all seen MD-11's doing wheelies on the cargo ramp. The weight would still be in the rear of the aircraft coming in thru the cargo door. Does anybody know why Boeing would put the main deck door in the back?
The pic here shows the door but not to the extreme that I had seen in the sales ad.
FriendlySkies From United States of America, joined Aug 2004, 4017 posts, RR: 5 Reply 1, posted (7 years 11 months 2 weeks 6 days 14 hours ago) and read 3834 times:
The 777 doesn't have a rear engine, so wheelies aren't really a problem. I'm sure Boeing put some thought into the location of the door, it may in fact be the best place for loading a 777.
PSAjet17 From United States of America, joined Dec 2003, 249 posts, RR: 0 Reply 2, posted (7 years 11 months 2 weeks 6 days 14 hours ago) and read 3823 times:
I would assume that when loading the upper deck, the pallets would be push forward and then the aft would be loaded. That should provide enough forward ballast to keep the aircraft from doing a wheelie.
Pictues From Canada, joined Nov 2004, 246 posts, RR: 0 Reply 3, posted (7 years 11 months 2 weeks 6 days 14 hours ago) and read 3806 times:
Also there is a device called a tail stand to prevent that from happening, or they teather the nose wheel to the ground. Those were forgotten on the planes that went onto their tail.
Ikramerica From United States of America, joined May 2005, 21045 posts, RR: 60 Reply 4, posted (7 years 11 months 2 weeks 6 days 14 hours ago) and read 3797 times:
I would also assume the door could be placed up front, or a second door added, per operator demand, no?
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UPS Pilot From United States of America, joined May 1999, 867 posts, RR: 3 Reply 5, posted (7 years 11 months 2 weeks 6 days 9 hours ago) and read 3594 times:
The 777 has no rear engine, mmmm, I never knew that I'm aware of the loading methods and items used to prevent wheelies. The comment regarding wheelies and the cargo door was a speculation of why the door would be in the rear. The question is why would Boeing put the door there? The 747 has a reason to have the rear cargo door but all other freighters have the door ahead of the wing. MD11,DC-8, A300/310, 72, 75, 76 all have the door in front of the wing.
Shenzhen From United States of America, joined Jun 2003, 1701 posts, RR: 2 Reply 6, posted (7 years 11 months 2 weeks 6 days 8 hours ago) and read 3561 times:
Could it be that when the cargo is loaded, it would need to be moved forward before the next pallet could be loaded, therefore the actual loading (except the first pallet) would be forward of the CG, not aft. With this in mind, there shouldn't be any willies.
B707Stu From United States of America, joined Feb 2005, 918 posts, RR: 4 Reply 7, posted (7 years 11 months 2 weeks 6 days 8 hours ago) and read 3553 times:
Quoting Shenzhen (Reply 6): With this in mind, there shouldn't be any willies.
That's the reason. Thanks Shenzhen, your "willies" for "wheelies" put a smile on my face.
AbirdA From United States of America, joined Jul 2005, 253 posts, RR: 6 Reply 9, posted (7 years 11 months 2 weeks 6 days 2 hours ago) and read 3293 times:
Quoting PSAjet17 (Reply 2): I would assume that when loading the upper deck, the pallets would be push forward and then the aft would be loaded. That should provide enough forward ballast to keep the aircraft from doing a wheelie.
My first thought exactly, although I'll take it a little further. With a cargo door forward of the wing, loaders must send the first pallets or containers to the rear of the aircraft and then work toward the front. this keeps the center of gravity as far aft as possible for as long as possible. With an aft cargo door like that depicted on the 777LRF, the first pallets or containers will be sent to the front of the aircraft to facilitate the continued loading of the aircraft. This, of course, will keep the center of gravity as far forward as possible for as long as possible. Kudos to Boeing for finding a simple way to insure against a load-induced tip of the plane.
Quoting Tod (Reply 8): This allows one door design to be used on both freighter and combi configurations.
Not quite. For some time now it has been clear that the FAA will NOT certify any new designs for Combi aircraft due to the concern of increased risk to passengers' lives in the event of unplanned impacts that could jar the cargo loose.
N1120A From United States of America, joined Dec 2003, 25869 posts, RR: 79 Reply 10, posted (7 years 11 months 2 weeks 6 days 1 hour ago) and read 3254 times:
Quoting AbirdA (Reply 9): Not quite. For some time now it has been clear that the FAA will NOT certify any new designs for Combi aircraft due to the concern of increased risk to passengers' lives in the event of unplanned impacts that could jar the cargo loose.
They will certify them with a fixed firewall between the two cabins. Still, unlikely a carrier would want that
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AbirdA From United States of America, joined Jul 2005, 253 posts, RR: 6 Reply 11, posted (7 years 11 months 2 weeks 6 days 1 hour ago) and read 3229 times:
Quoting N1120A (Reply 10): They will certify them with a fixed firewall between the two cabins. Still, unlikely a carrier would want that
If that is true, my apologies for providing somewhat inaccurate info. I was under the impression that there was no way the FAA would be certifying the carriage of pax and freight on the same deck of any new design. Not doubting you, just curious to learn more about current Combi policies. Do you have a link to info on this, N1120A?
HighFlyer9790 From United States of America, joined Jul 2005, 1236 posts, RR: 0 Reply 13, posted (7 years 11 months 2 weeks 6 days ago) and read 3182 times:
Quoting UPS Pilot (Thread starter): The only freighter by Boeing, Airbus or MDD/Douglas to date is the 747
If i understand this correctly, what about all the other frieghters????
757F
767F
etc.
did you mean with the cargo loading door in the rear?
Please clarify what you meant UPS Pilot
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UPS Pilot From United States of America, joined May 1999, 867 posts, RR: 3 Reply 14, posted (7 years 11 months 2 weeks 5 days 22 hours ago) and read 3086 times:
High Flyer, the 747 is the only heavy freighter with the door behind the wing instead of in front of it.
I figured out the reason (I think) It doesn't specify if it will use a 9 g net or a ridgid barrier between the flight deck and the cargo main deck. Looking at both the 9 g net would not allow for the stretch if needed between the cargo door and the flight deck. The ridgid barrier does not need the extra room but it does allow for more cargo space. This typically means there is one position to the left of the door on the main deck then all others are from the door down. It doesn't appear there is enough space to allow for this if the door is placed to the front of the wing.
AbirdA From United States of America, joined Jul 2005, 253 posts, RR: 6 Reply 18, posted (7 years 11 months 2 weeks 5 days 21 hours ago) and read 2949 times:
Quoting Glom (Reply 17): It says that the freighter has a range of less than 5000NM. I thought it was based on the 772LR?
Dedicated freight aircraft, if i understand correctly, tend to dedicate a higher portion of their MTOW to fixed payload than do their passenger counterparts. Therefore, the maximum fuel load is decreased. In short, freight companies find it more desirable to carry larger weights over just marginally long distances rather than taking low loads over the longest routes.
Ha763 From United States of America, joined Jan 2003, 3494 posts, RR: 6 Reply 19, posted (7 years 11 months 2 weeks 5 days 19 hours ago) and read 2897 times:
Quoting AbirdA (Reply 11): I was under the impression that there was no way the FAA would be certifying the carriage of pax and freight on the same deck of any new design. Not doubting you, just curious to learn more about current Combi policies.
Alaska had plans to convert 4 of their 737-400s into combi aircraft with a fixed configuration of 70 pax and 4 pallet positions.
Considering that no 737-400 combis were built by Boeing, the converted 737-400s would need to be certified by the FAA. Alaska would not have considered it if there was no possibility of it being certified. They also considered the 737-700, which Boeing already makes in a fixed combi configuration for the US Navy or the 737-300, both which would have a fixed configuration of 70 pax and 3 pallet spaces. Again, it would not be considered as an option if the FAA wasn't going to certify it.
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I'm aware of the loading methods and items used to prevent wheelies. The comment regarding wheelies and the cargo door was a speculation of why the door would be in the rear. The question is why would Boeing put the door there? The 747 has a reason to have the rear cargo door but all other freighters have the door ahead of the wing. MD11,DC-8, A300/310, 72, 75, 76 all have the door in front of the wing.
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