Cardinal, the contract will not protect you from being discharged for refusing to fly what you determine is an unsafe airplane. I worked for union carrier where a Captain refused to fly an airplane with an item he considered unsafe, the company said it was properly deferred via the MEL, take it or you do not work here. Another union pilot flew the airplane that night. The union could not restore his job. Now if there is a company that wants you to fly illegally then you owe it the company and yourself to quit.