US A330's
 

Where are US Airways' A330's mainly based?

On what routes do they fly?

Or even "How long will they fly?"

US just missed a payment on them, although there is a ten-day grace period.

True; USAirways has suspended lease payments temporarily.

US 330s fly a variety of trans-atlantic sectors only. To my knowledge they never fly domestic. I know they fly CLT-LGW, PIT-LGW, PHL-LGW, PHL-CDG, PHL-FCO and PHL-MAN or FRA. Mostly, they're based in PHL, but occasionaly they fly out of other hubs, CLT/PIT.
http://www.starmanauctions.com/twa.gif

The payments were missed on 5 of the 330's. More fun within the bankruptcy proceedings. There is one daily PHL-SJU turn in addition to the transatlantic flying. March schedule shows PIT-FRA, PHL-FRA, PHL-LGW, PHL-MAN, and PHL-FCO as well.

USAirways 330s are based in CLT, PIT, PHL and fly to FRA , FCO LGW, MAN, CDG, and SJU. Starting on Apr 16th, they will also serve Madrid with the 330. I feel certain the payment was not made to Airbus to put additional pressure on the pilots, as they are currently in court trying to salvage their retirement plan. The company has asked the bankruptcy judge to allow termination of the plan, and final hearings are being held on the 28th of Feb.