We propose a comprehensive and systematic contingency plan generation framework to deal with lost communication in UAVs. ATC regulations are explicitly incorporated into our system. Our proposed framework was motivated by our recent work for the Naval Air Station at Patuxent River. In should be noted that our earlier framework was very general, as we have designed a system which can deal with many types of pop-up threats such as enemy attacks, internal system faults, external interferences, etc. Currently, we have been focusing on generating contingency plans for engine out problems for the Navy. In this NASA Phase 1, we will focus on generating contingency plans for lost communication. Our proposed approach has one key component known as Risk Management Plan (RMP), which assesses mission risk of a given air task order (ATO) and provides solutions for known or unknown threats throughout the course of the mission. Four sub-plans are used to support RMP: Situation Analysis (SA), Preparedness & Prevention Plan (PPP), Incident Response Plan (IRP), and Rescue & Recovery Plan (RRP). We propose to apply case based reasoning (CBR) in two modules (PPP and IRP) to generate contingency flight paths, contingency points, safe points, and incident response rules. In CBR, we can easily incorporate ATC regulations, which can be formulated as used cases in the CBR.