Think about it, when a 747 is on the ground, it has 20 tons of airplane resting on the tires. I’m thinking the foot jack is not going to do the job. When it’s off the ground, it’s usually moving too fast for truly convenient tire changing, although I suppose it’s possible that they circle for awhile and send out a Wellenda.
A followup question: what are the tires made of? Surely, they’re not inflated like car tires, right?
The tires are pretty much the same as a car tire, except they have different treads. Many aircraft use tubed tires on split rims. So I suppost you could change a tyre by removing the outer rim and taking off the old one, then inserting a new tube and tire and reassembling the rim. I’ve heard of people taking off the outer split rim and filling their flat tires with smooth gravel when they get a flat out in the bush.
But there are jack points on the aircraft, as shown by this PDF file. Probably easier to jack it up than to change on the ground.
Thieves gotta drag some BIG-ASS blocks to put the plane on top of.
No, dudes, they land the plane upside down, leaving the tires exposed in the air. Pull up a giant ladder and a crane, change tires. Then have another plane tow the other up to an altitude where it can turn over again.
You know what’s a pisser? When your next door neighbour has a couple of 747s on blocks on his front lawn. With a mean old dog chained up to one.
Really? I don’t have experience with the big ones, but I’ve worked with large business jets and small regional jets. They use bias-ply tubeless tires. There’s a handy-dandy jacking point built into each axle, between the twin tires. A ten-ton hydraulic jack does the trick. It’s about the size of two loaves of bread, weighs 65 lb and can be pumped up by hand or driven by shop air.
I’d suspect that all larger jets use tubeless tires, for their simplicity of operation and weight saving over tubed ones.
Interestingly, large aircraft also have jacking points on their wings and fuselage so the entire landing gear can be maintained or replaced if necessary. (This is also a useful feature during manufacture.) It’s very odd to see an airplane sitting in the hangar with no landing gear.
**YOU &%@$! QUIT TALKING &#^@%! ABOUT ME OR I’M CRANKING UP THE ALABAMA’S GREATEST HITS CD ALL THE #^@&! WAY AGAIN, JOHNNY!
On military jets at least, the tires are inflated with nitrogen. Wouldn’t be surprised if that is done on large commercial aircraft.
How do you change the tires? Just like you do on a car, as far as I know. There are special jacks for most airplanes that fit jack pads or flanged to allow lifting the airplane.
I’ll have to admit that I don’t know if split rims are used on larger aircraft, but GA aircraft often do. Obviously you’re unlikely to find a 747 or even a regional jet on an unimproved strip in the Alaskan bush. Of course the cravel trick won’t work if you don’t have split rims.
No one’s posted the real answer yet. They don’t have to do it while the plane’s on the ground.
They do it in the air. That’s right, once they figure out they need to change the tire, they just have a mechanic hop on board and then crawl down in there to swap it out once the gear’s up. If they’re good at it, they can usually be back up top by the time the movie starts.
Kathie-Lee Gifford runs a company which uses child slave-labor to change the tires in-flight while the landing gear is retracted. It’s dangerous work, but they get candy if they make it to the ground. 
Yeah, that’s done on commercial aircraft too. It’s done to help suppress (or at least to not aggravate) a tire fire.
There are jack points under the gear; jack it up, pull the wheel and tire, put on a new one. The wheels are in two halves, and if you want to put a new tire on a wheel, you have to disassemble it; but for everyday tire changes out on the flightline you change the wheel and tire together as one unit.
Commercial airliner tires are filled with nitrogen. There was a nasty accident in 1986 on a Mexicana 727 when they filled a tire with air. The tire got hot (I think they had been taxiing quite a while and the brakes were hot) and the fumes from the rubber and the oxygen in the air inside the tire formed an explosive mixture. The tire exploded while the gear was up, 14 minutes after the flight left Mexico City, and ruptured fuel, hydraulic and electrical lines and air conditioning ducts that passed near the wheel. There was enough heat still present that fuel from the broken lines ignited, and the plane crashed, killing 167 people.
Jacking up an entire 747 doesn’t make sense to me. Puting suspension under the wings and partially retracting the gear in question sounds more reasonable. Maybe, if I could actually see what is meant by a “jack point” I’d understand the process better.
P.S. Did anyone get my Wallenda joke? Anyone?
To change a tire on a 747 (or other jet) you don’t jack up the whole plane. Each landing gear strut or leg has two or four tires at the bottom connected by fixed axles (called a “truck”). The truck’s jacking point (a reinforced hemisphere about two inches in diameter) is built into the bottom and faces the ground. The top of the jack fits into this. You jack up only the strut that has the tire you want to change. All the other gear struts (and tires) stay on the ground. You only have to lift the tires clear of the ground, so the distance the jack lifts is equal to the compression of the tire sidewall, plus a little more. It’s only a few inches even on the largest jets.
Jacking an entire aircraft on its structure is a much larger enterprise. If the jacks are lifting on the structure and not on the landing gear, the aircraft has to be lifted much higher, because the landing gear struts have long shock absorbers which are normally compressed as the aircraft stands on them. These will extend as the aircraft is lifted until they become completely unloaded, leaving the wheels dangling under the aircraft. This is several feet of travel. Care must be taken to keep the aircraft level as it is lifted, or it may fall off the jacks. I have seen this happen. It is not fun.
To clarify, the top of the jack is shaped like a cup and fits over the jacking point, not into it.
Damn it, panamajack you’ve let out confidencial information without consulting me![sup]which means he beat me to it.[/sup]
Of course. But there aren’t many Wallenda’s left are there? Those still in the business must be really busy changing all those tires.
Ohhhhhhh! I get it! The Flying Wallenda trapeze act! Ha!