If a large passenger airliner needs repair at a remote airport without services, are there "flying repairshops" that can swoop in and do the work on site?
If you can, you'll fly in maintance yourself to get it fixed, perhaps by chartering a cargo plane on the way. If you can land the aircraft, you can probably get any spare part in through the same runway, with varying degrees of difficulty.
If it's bad, Boeing has an Aircraft On Ground team who should be able to fix pretty serious damage. Often, it may just be patched up until it's good enough to fly to get it to a place with better facilities.
If the problem is a bad engine and the aircraft is a 747, the most cost effect solution is usually a 3-engine ferry to a repair station. From memory, the protocol to be observed includes:
- The Captain must do the flying.
- Only the cockpit crew can be aboard.
- The fan must be tied down to prevent it's rotation in flight.
- A specific takeoff procedure is to be followed.
At the two 747 carriers I worked for, we usually did a 3-engine takeoff in the sim on our 6-month checks. I did two of them for real, and it's no big deal.
No airport capable of handling widebodies will have no services at all, but of course many places lack a full maintenance shop.
As mentioned elsewhere, Boeing has a go team that can get most repairable damage brought back to flyable condition. "Flyable" does not necessarily mean "normal, scheduled service" - it means able to leave the remote field and limp back to a facility able to do the proper work. This could easily be Seattle or Hamburg from Johannesburg. If you want to reposition an aircraft for maintenance you can have a LOT of stuff broken - basically if the engineers say they'll ride in it, and you avoid overflying large cities, you're good.
Several large aircraft have an option to carry an extra engine on the wing to a remote grounded aircraft - expensive, but cheaper than cargo (it can be on a scheduled revenue flight). Put a couple of mechanics on board and the job's done in a day or two. The bad engine comes back the same way.
That would depend on the damage that needs to be repaired.
Some repairs (like replacing an engine) can be done on site.
For more serious damage that can't be fixed on site they will make a quick patch and then fly the aircraft to a facility capable of properly doing the repairs while taking care to not aggravate the existing problem.