Dirty oil after Crossing atlantic up from South of spain

[andysim212]

Hi, over the last 2 weeks I have been flying back some long legs from South of Spain (as FSEconomy keeps track of aircraft location) and have crossed the Atlantic (Via Iceland).  On arrival at KBOS I checked the maintenance hanger (first check since starting my trip) and found I had "Dirty" oil.  

 

I Changed it but I thought I read somewhere it should never need changing except at TBO.  Did I do something wrong? Ive been keeping everything in the green and cruised at <80%.  About 50 hours from new.

 

 

Thanks

[Goran_M]

Check if you have accelerated wear turned on