A system includes a transmitting line replaceable unit (TLRU) configured to receive messages including instructions for avionics receiving line replaceable units (RLRUs). The system further includes a memory configured to store validation data including a set of expected messages. A monitor is further included and is configured to monitor messages received at the TLRU and further configured to determine whether received messages are valid based on at least a portion of the set of expected messages stored in the memory. A plurality of RLRUs are further included and configured to receive message from the TLRU and to execute the instructions included in the received messages.