Structural health monitoring for critical aircraft structures posts significant challenge and interest to most military and commercial applications. We anticipate that by the end of our Phase II effort we should have developed a working prototype of the proposed MFSNS technology for damage and precursor characterization in complex aircraft structures. This NDE/SHM technology should have many applications in NASA, other government agency and industries. For NASA, this technology is especially critical to protect the platforms' and crews' safety. For military applications, the enabling technology will increase an aircraft's readiness and allow the cost-saving Condition Based Maintenance (CBM) of aircrafts, ships, ground vehicles and infrastructures to be implemented. In commercial sectors, this advanced SHM technology will benefit the maintenance decision for air and space vehicles, civil structures and power plants. This new NDE/SHM technology could significantly extend an aircraft?s service life, reduce maintenance costs, and protect the safety of critical assets.