This paper presents an overview of the B-1B avionics safety analysis. Nuclear safety and terrain following flight safety were major concerns. Analyses demonstrate that all safety requirements were met. Extensive coordination with the B-1B System Program Office and the support of major Boeing B-1B avionics subcontractors was required. The paper summarizes nuclear safety effort. It presents significant details of the terrain following analyses to give insight into the technical and integration challenges. Lessons learned are included.