The LFT&E statute requires a LFT&E program to include Full Up System Level (FUSL) testing unless a waiver from FUSL is granted with a certification by the Under Secretary of Defense for Acquisition and Sustainment or the DoD component acquisition executive that FUSL testing would be unreasonably expensive and impractical. A waiver package must be sent to the congressional defense committees prior to Milestone B, or, in the case of a system or program initiated at Milestone B, as soon as practicable after Milestone B, or if initiated at Milestone C, as soon as practicable after Milestone C. Typically, this should occur at the time of Test and Evaluation Master Plan approval. The waiver package must include a Director, Operational Test and Evaluation approved alternative plan for LFT&E of components, subassemblies, or subsystems, and, as appropriate, additional design analyses, modeling and simulation, and combat data analyses.