Oasis From Canada, joined May 2008, 62 posts, RR: 0 Posted (4 years 11 months 2 weeks 3 days 16 hours ago) and read 4493 times:
Hi
I was wondering what would happen to an A340-200/300 if the middle gear (the one under in between the wings) would be removed (if that is even possible to just have it be removed?) Would the middle part of the fuselage collapse? Because the only difference between an A330-300 and an A340-200/300 is that one has 4 engines, and the A330 doesn't have any gear in the middle. Is it a weight issue? I think I remember seeing a picture of a CX A340 at Kai Tak without the middle gear.
I hope that made sense :P
-Ben
Aeroflot can fly Moscow to LA, I bet your airline can only fly half way
I am not 100% sure for the A340. But for the MD11 you can remove the center landing gear as well. Or let it be retracted. Nothing would collaps but you have a huge reduction in the maximum weights. The MTOW reduces to 220 tons instead of 286 tons. Same for the landing weight. But I don't know the figures there.
So I bet it is possible for the 340 as well. And nothing would collapse.
Vikkyvik From United States of America, joined Jul 2003, 8223 posts, RR: 28 Reply 2, posted (4 years 11 months 2 weeks 3 days 15 hours ago) and read 4456 times:
AIRLINERS.NET CREW PHOTO SCREENER
Quoting WILCO737 (Reply 1):
I am not 100% sure for the A340. But for the MD11 you can remove the center landing gear as well. Or let it be retracted. Nothing would collaps but you have a huge reduction in the maximum weights. The MTOW reduces to 220 tons instead of 286 tons. Same for the landing weight. But I don't know the figures there.
So I bet it is possible for the 340 as well. And nothing would collapse.
Hey WILCO, is it on the MD-11 that the center gear is non-load bearing at lighter weights? As in, it'll actually be off the ground?
I'm pretty sure that's the case for EITHER the MD-11 or the A340....but I don't remember which one.
However, there have been cases when the center gear is inoperable for some reason. The airplane can still fly (I guess the center gear gets MEL'd?), but I'd think the weights are reduced, as Phil said.
Buckfifty From Canada, joined Oct 2001, 1314 posts, RR: 21 Reply 3, posted (4 years 11 months 2 weeks 3 days 15 hours ago) and read 4456 times:
Quoting Oasis (Thread starter): Hi
I was wondering what would happen to an A340-200/300 if the middle gear (the one under in between the wings) would be removed (if that is even possible to just have it be removed?) Would the middle part of the fuselage collapse? Because the only difference between an A330-300 and an A340-200/300 is that one has 4 engines, and the A330 doesn't have any gear in the middle. Is it a weight issue? I think I remember seeing a picture of a CX A340 at Kai Tak without the middle gear.
The middle gear itself can be stowed in the uplocked position, with a reduced Max Ramp Weight / Max Takeoff Weight. Otherwise it has no effect at all on the Max Landing Weight. In effect, without the centre gear, the weights which the A340 operate at are more or less those of a maxed out A330. However, this obviously depends on what configurations / standard either aircraft are built to when you do the comparison.
The centre gear itself is not a landing load bearing gear. Therefore, if we had a main gear stuck in the stowed position, we must land without the centre gear in order not to damage the fuselage. The only way to do that is via a gravity extension.
Starlionblue From Hong Kong, joined Feb 2004, 15871 posts, RR: 66 Reply 4, posted (4 years 11 months 2 weeks 3 days 15 hours ago) and read 4455 times:
Definitely a weight issue. The 340 is designed for longer haul flights with higher weights.
You can probably retract it for maintenance purposes. As Wilco737 points out the MD11 can have it MELd. I believe it was MD11Engineer who posted the checklist for such an event, ending with "inform the pilots of the coming weight and balance nightmare".
"There are no stupid questions, but there are a lot of inquisitive idiots." - from Citadel by John Ringo
WingedMigrator From United States of America, joined Oct 2005, 2025 posts, RR: 56 Reply 5, posted (4 years 11 months 2 weeks 3 days 15 hours ago) and read 4452 times:
Quoting Buckfifty (Reply 3): The centre gear itself is not a landing load bearing gear.
What else is its function then-- ornamentation?
Or is it something having to do with the bearing capacity of aprons and taxiways?
WILCO737 From Greenland, joined Jun 2004, 8476 posts, RR: 78 Reply 7, posted (4 years 11 months 2 weeks 3 days 15 hours ago) and read 4445 times:
AIRLINERS.NET CREW HEAD MODERATOR
Quoting Vikkyvik (Reply 2): Hey WILCO, is it on the MD-11 that the center gear is non-load bearing at lighter weights? As in, it'll actually be off the ground?
As far as I know, it has always contact to the ground. Even at lighter weight. I think it was the 340 where it is "airborne" when empty.
Quoting Starlionblue (Reply 4): As Wilco737 points out the MD11 can have it MELd. I believe it was MD11Engineer who posted the checklist for such an event, ending with "inform the pilots of the coming weight and balance nightmare". Wink
Oh yeah, the weight and balance nightmare. For us cargo it doesn't make any sense to fly without that gear. You cannot take much load with you then. So, better get a new one first
Mir From United States of America, joined Jan 2004, 19715 posts, RR: 56 Reply 8, posted (4 years 11 months 2 weeks 3 days 12 hours ago) and read 4395 times:
Quoting WingedMigrator (Reply 5): Or is it something having to do with the bearing capacity of aprons and taxiways?
Precisely. Only eight main wheels puts too much load on each for the taxiways to bear. Thus the 340 has ten. The 340NG and 777 have twelve (though the 777 has no center gear). You can go without the center gear on the 340 or MD11, but you're going to be weight restricted so as to not exceed taxiway strength limits.
Until recently, 777-300s and 340-600s couldn't use the taxiway bridges at JFK due to the fact that despite the extra wheels, they still have very high pavement loading, more than what the bridges could withstand. The bridges have since been rebuilt and now there are no restrictions.
-Mir
7 billion, one nation, imagination...it's a beautiful day
Tristarsteve From Sweden, joined Nov 2005, 3693 posts, RR: 34 Reply 10, posted (4 years 11 months 2 weeks 3 days 11 hours ago) and read 4366 times:
An engineer friend of mine was working in Sanaa on the BA DC10 when it was a scheduled flight there. I think it was the last flight, anyway he had no spare mainwheel, and needed to change a wing gear wheel. So they removed a S wheel from the centre gear and fitted it on the wing posn, then retracted the centre gear and flew the aircraft back to LGW.
HAWK21M From India, joined Jan 2001, 31201 posts, RR: 58 Reply 11, posted (4 years 11 months 2 weeks 3 days 10 hours ago) and read 4326 times:
Quoting Tristarsteve (Reply 10): An engineer friend of mine was working in Sanaa on the BA DC10 when it was a scheduled flight there. I think it was the last flight, anyway he had no spare mainwheel, and needed to change a wing gear wheel. So they removed a S wheel from the centre gear and fitted it on the wing posn, then retracted the centre gear and flew the aircraft back to LGW.
Interesting.Reminds me of the MEL move on B752 using the serviceable secondary EICAS display on the u/s EHSI position
regds
MEL
SlamClick From United States of America, joined Nov 2003, 10062 posts, RR: 71 Reply 14, posted (4 years 11 months 2 weeks 2 days 22 hours ago) and read 4136 times:
Quoting WingedMigrator (Reply 5): is it something having to do with the bearing capacity of aprons and taxiways?
For sure, here in the US, load bearing capacity for airports is driven by wheel configuration.
However, I always assumed, from the placement, that it was specifially increase max zero-fuel weight including weight from centerline tanks which, structurally, behaves like payload.
Happiness is not seeing another trite Ste. Maarten photo all week long.
BuckFifty From Canada, joined Oct 2001, 1314 posts, RR: 21 Reply 16, posted (4 years 11 months 2 weeks 2 days 2 hours ago) and read 3944 times:
Quoting SlamClick (Reply 14): However, I always assumed, from the placement, that it was specifially increase max zero-fuel weight including weight from centerline tanks which, structurally, behaves like payload.
The 333 and 343 both have very similar MZFW's. And without the centre gear down, the 343 is limited to a MTOW which is, again, similar to that of a 333.
With the MLW virtually the same for both aircraft, one would assume that the centreline gear is indeed there to increase the MTOW / MRW, by increasing the footprint for a lower ACN.
The centre tank on the 340, incidentally, is an integral tank in the wingbox, which is different than the pallet loaded ACT. Not sure if anyone uses those anymore...
Askr From Poland, joined Mar 2008, 45 posts, RR: 0 Reply 17, posted (4 years 11 months 2 weeks 2 days 1 hour ago) and read 3940 times:
Quoting Askr (Reply 15): There is a pic in the database of a Varig MD11 or DC-10, cant recall, where the middle landing gear... fell off. Well, at least the bogey.
Maybe MD11 will have a pic of that somewhare
Damn, it was supposed to be WILCO737
Sorry for the mixup
ATC-PL Wanabe :) - 2nd application is in... 11 July...
Vikkyvik From United States of America, joined Jul 2003, 8223 posts, RR: 28 Reply 18, posted (4 years 11 months 2 weeks 2 days ago) and read 3908 times:
AIRLINERS.NET CREW PHOTO SCREENER
Quoting WILCO737 (Reply 7): As far as I know, it has always contact to the ground. Even at lighter weight. I think it was the 340 where it is "airborne" when empty.
OK, that's what I thought. Thanks.
Quoting Askr (Reply 17): Damn, it was supposed to be WILCO737
That's his fault for switching aircraft on us
"Two and a Half Men" was filmed in front of a live ostrich.
Airbus_A340 From Hong Kong, joined Mar 2000, 1554 posts, RR: 21 Reply 20, posted (4 years 11 months 2 weeks 1 day 2 hours ago) and read 3738 times:
Something you might find interesting, when unloaded, the A340 centre landing gear doesn't touch the ground, it hangs a couple of inches off the ground, until loading/refuelling.
Viscount724 From Switzerland, joined Oct 2006, 21492 posts, RR: 24 Reply 22, posted (4 years 11 months 1 week 6 days 20 hours ago) and read 3561 times:
Quoting WILCO737 (Reply 1): But for the MD11 you can remove the center landing gear as well. Or let it be retracted. Nothing would collaps but you have a huge reduction in the maximum weights.
DocLightning From United States of America, joined Nov 2005, 16824 posts, RR: 57 Reply 24, posted (4 years 11 months 1 week 6 days 7 hours ago) and read 3472 times:
Sponsor Message: 
From Canada, joined May 2008, 62 posts, 
From Greenland, joined Jun 2004, 8476 posts, 
From United States of America, joined Jul 2003, 8223 posts, 
From Hong Kong, joined Feb 2004, 15871 posts, 
From United Kingdom, joined Jun 2001, 2138 posts, 
From Sweden, joined Nov 2005, 3693 posts, 
From India, joined Jan 2001, 31201 posts, 
This photo clearly shows this:
From Poland, joined Mar 2008, 45 posts, 
From Switzerland, joined Oct 2006, 21492 posts, 
Sponsor Message: 
Printer friendly format
