Apparatus and methods used to prevent an operator from inadvertently dropping a string into a wellbore during assembling and disassembling of tubulars. In one instance, an interlock system is used to control the operations of a gripping apparatus connected to the top drive and a spider such that at least one of the top drive or the spider retains the tubular. The interlock system allows the spider to open when the gripping apparatus is supporting a load of the tubular or is in position to support a load of the tubular.