NOTICE ADVISORY TO NAVSTAR USERS (NANU) #038-93053 SUBJ: PRN12 UNUSABLE 051/0106-051/0119 1. CONDITION: PRN12 (SVN10) WAS UNUSABLE ON DAY 051 (20 FEB 93) BEGINNING 0106 UTC UNTIL DAY 051 AT 0119 UTC. 2. USERS OF GPS ARE CAUTIONED THAT THE SYSTEM IS NOT YET FULLY OPERATIONAL. SIGNAL AVAILABILITY AND ACCURACY ARE SUBJECT TO CHANGE DUE TO AN INCOMPLETE CONSTELLATION AND OPERATIONAL TEST ACTIVITIES. 3. POC: 1LT SKINNER AT COMMERCIAL (719) 550-6378 OR DSN 560-6378.