Campagnolo Athena - Lost plastic part on front derailleur. Now the chain is droping on upshifting Somehow the plastic part on the side/front of the derailleur is lost. Now I can't shift properly because the chain drops to the outside on an up shift.

The plastic part is visible in this image. Its the black thing.



Is there a spare part available or is this a warranty case?
The spare part code is 5-FD-RE116 for double or FD-AT016 for triple and it's available from several online shops. LBSes specializing in road bikes should have it too.

Check out the spare parts catalogue from Campagnolo: http://www.campagnolo.com/media/files/035_250_Catalogue_spare%20parts_tools_Campagnolo_2015_part_A.pdf