When the recent Time Machine and AirPort Updates 1.0 update was released, users quickly discovered that the update enabled an AirPort Disk to be used as a backup drive for Time Machine. Much rejoicing ensued, since the change meant that it wasn't necessary to fork out the dough for a Time Capsule if you already own an Airport Extreme Base Station. Still, some people were still a bit suspicious of the change. The suspicion seems to be correct, too. Glenn Fleishman reports at TidBITS that Apple confirmed to him that the Time Machine + AirPort Disk combination is officially "unsupported."

So what does "unsupported" mean, anyway? Well as some intrepid users have already discovered, it means that Apple won't help you out with any problems related to a Time Machine backup to an AirPort Disk, which could be problematic if you break it. It's also possible that the functionality either won't work quite right, will break somehow (possibly losing your backups), or will be removed by Apple in the future. But if you're willing to accept those caveats, then go for it.

As somewhat of an aside, I'm surprised that Apple still hasn't done anything official about this. The company could either issue a statement or remove the functionality, but hasn't done either, despite Fleishman prompting the company for a statement since March. So far, it appears that Apple is taking the same kind of "silence as permission" approach that is has done with iPhone hacking, but it would be nice if it could at least let people know that the particular usage isn't supported. I also wouldn't be particularly surprised to see the functionality disappear in the next AEBS or Time Machine update, though, so I wouldn't recommend using the Time Machine + AirPort Disk trick as your sole backup solution.