Just browsed the a.net and got this photo. I'm always interested in knowing how a tyre replacing looks like and how long it usually takes to do so. I remember I once onboard an SQ flight SIN-HKG and it was delayed for about 45min as one of the tyres of the fully loaded B744 was busted and needed to be replaced immediately.
Well there you go. I remember seeing a documentary on NGC where they showed MX at FRA changing a tyre (wheel) of a LH 744. It took them somewhere around an hour. It was so nice to see the machines they had, especially the jack that can lift a 744 nosegear! That thing isn't big at all, and uses pressure from the aircraft's tyres to power it! The most difficult part were the bolts that held the wheel in place.. you wouldn't believe how complicated that mechanism is.
"Get your facts first. Then you may distort them as much as you please" -- Mark Twain
Kwcarolma From Australia, joined Jun 2006, 42 posts, RR: 0
Reply 2, posted (8 years 4 months 5 days 20 hours ago) and read 6458 times:
Thanks EHHO! But well I guess it might take shorter than 45mins because the captain of my flight told us that it would take like 20mins in the first place. But after then he announced that it would take a bit longer as the technicans found the aircraft was too heavy to be lifted off!! So I guess it takes shorter than that if everything goes smoothly?
Vref5 From , joined Dec 1969, posts, RR:
Reply 3, posted (8 years 4 months 5 days 20 hours ago) and read 6433 times:
Not being an A&P (airframe & powerplant mechanic), I'll leave that to them.
Tangentially related: I remember an interesting comment told by an Air Canada A&P once, some time ago, that they usually retread tyres for certain wheels, and replace for others when done as preventative maintenance.
E.g. the high wear and stress areas got brand new tyres, while ones with less wear/stress usually were retreaded. This was done as a cost saving measure after careful analysis and reasonable confidence that this didn't have safety implications. Seems to have done reasonably well with that programme.
Bluewhale18210 From United States of America, joined Aug 2006, 237 posts, RR: 0
Reply 6, posted (8 years 4 months 5 days 19 hours ago) and read 6372 times:
Witnessed the process a few times. Takes anywhere from 30min-1hr on a 744 main gear. That is when all parts/tools are in place. For long haul flights the weight is usually a problem. A 744 getting ready to get underway for a flight across the Pacific can sit on the ramp with more than 700,000lbs, just metal and fuel. It usually requires a bigger jack that is not too common, and MX might have to find who has it.
All in all the whole thing is not much different from changing a car tire, it is just tricky on the weight.
JPS on A300-600RF A319/320 B737-400/800 B757-200F B767-300F CRJ-200/900. Looking to add more.
TristarSteve From Sweden, joined Nov 2005, 4116 posts, RR: 33
Reply 7, posted (8 years 4 months 5 days 17 hours ago) and read 6324 times:
Quoting Bluewhale18210 (Reply 6): All in all the whole thing is not much different from changing a car tire, it is just tricky on the weight
A widebody mainwheel weighs around 200kg. You need the right equipement to manhandle it into posn.
And it depends what 'busted' means. If the tyre is flat, then you need to change both wheels on the same axle. And it is a little more complicated than a car wheel. The locking nut has to be torqued at up to 600ftlbs, then locked in place. There is also the TPIS transmitter and the Antiskid transmitter sitting there in the axle to get in the way. And when you slide the new wheel over the brake unit all the segments have to line up as it goes on.
With the right tools and enough mechs then 20mins for a B737 nosewheel up to an hour for a B777 centre mainwheel.
And when you have finished you have to blow it up with nitrogen to around 200psi.
A busy hub station will beat these times easily because they do it all the time and are ready. I will take longer. I have 7 flights a day B777 B757 B767 A320 and change about one wheel a year. So when it happens I have to go and get all the gear out of stores, and find some help. On a B737, I can change a mainwheel on my own, but not on the A320 and bigger.
Quoting Vref5 (Reply 3): that they usually retread tyres for certain wheels
Nearly all our tyres are retreaded. Rarely see a new one. They can be retreaded up to 12 times.
HAWK21M From India, joined Jan 2001, 31713 posts, RR: 56
Reply 8, posted (8 years 4 months 5 days 17 hours ago) and read 6304 times:
Depending on the cause of the Unserviceability of the Tire concerned.Did the Aircraft roll with the Flat tire etc.
If proper Equipment are available & the Temperatures are average,approx 30-45 minutes depending on the Skill of the A&P.
If the Aircraft rolled with the Flat tire,Both tires on the same Axle would need replacement as the Single tire is not build to carry both tire loads [eg in 737s].
If the Deflation was due to over heated brake,then the Brakes would need Inspection and/or Replacement.
Fr8Mech From United States of America, joined Sep 2005, 5835 posts, RR: 15
Reply 9, posted (8 years 4 months 5 days 17 hours ago) and read 6280 times:
A wheel assembly will take anywhere from 20 minutes to an hour. A couple of factors afftect the time. The biggest factor, in my humble opinion (barring a flat tire), woud be the temperature of the tire. They get pretty darn hot. At Delta we had these big, asbestos gloves to handle quick-turn tire changes.
As for retread use: the only operator I ever worked with that used new tires was PanAm and they, as I recall, required their use only on the body gear of a B747, otherwise, retreads it was.