As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) WHILE PERFORMING ENGINE MAINTENANCE, IT WAS NOTICED THAT THE AIR CONDITIONING IDLER SHEAVE (PULLEY) WAS NOT ALIGNED WITH THE COMPRESSOR PUMP SHEAVE AS IS NORMALLY THE CASE. FURTHER INVESTIGATION WARRANTED DISASSEMBLY, AND IT WAS FOUND THAT THE IDLER SHEAVE BEARING HAD COMPLETELY DISINTEGRATED. SUBSEQUENT LOADS IMPOSED ON THE SHEAVE RESULTED IN WEAR ON THE ASSOCIATED PARTS AND HARDWARE REQUIRING THEIR REPLACEMENT.