A positive locking device is a device used in conjunction with a fastener in order to lock the fastener. This means that the fastener cannot work loose from vibrations. The following is a list of positive locking devices:

• A split beam nut and a split pin
• A castellated nut and a split pin
• A hex nut or cap screw and a tab washer
• A hex nut or cap screw and a lock plate
• Safety wiring with various types of fasteners