If I suggested that the OP's flight diverted due to weather, I apologize for the confusion; I'm not as up to speed of the specifics as you seem to be, apart from the OP's account, in which he told us the diversion was announced prior to departure.

I'd also like to point out that an airplane can have "issues" that impact its range or restrict how/where it can fly, yet still be airworthy. Furthermore, in spite of the fact that I don't hold an especially high regard for Philippine Airlines, I don't believe its pilots would attempt to fly an airplane that they suspected to be unfit for the mission at hand.