Most aircrews arrived for SR-71 training with an Air Force Top Secret (TS) security clearance. However, the SR-71 program was compartmentalized and demanded a Special Access Required (SAR) security clearance, a rare classification, reserved only for highly sensitive military programs. The unclassified SAR name for the SR-71 program was called "Senior Crown". The Senior Crown security clearance was issued at Beale for all personnel who had a "need to know" about the SR-71 program .

Once you were briefed into the Senior Crown access program, aircrews signed for, and were issued flying manuals at the squadron. To control all classified documents issued to Habus, an entire wall of the squadron administration room was lined with security safes. This was a Habu's first introduction to an increasing maze of combination locks, cipher codes and secrets he would have to memorize in order to fly a mission.