I am a college student finishiing my mastes degree . I have worked part time on the ramp at ups for the past 9 years , also for the past two years i have worked as an air exception driver(part time air driver) delivering EAMs in the morning. In the past to weeks my full time management has brought in full time ground package drivers to deliver EAMs and the are bumping me out of my EAMs work. I was allways told that eam work went first to fulltime combo air drvers then to part time air drivers then if no air drivers then fulltime ground drivers. In the past two weeks my suppervior is saying that the order is combo air drivers then full time ground then partime air drivers. this semes tto counterdict some of the language article 40. i have been researching this and it seem since i have been doing this for so lond that this work falls under past practice for me. any full ground driver should not have any rights to bump me out. Is there anyone shopstuwards or BA that can help me with this question.