Narrative:

Aircraft is equipped with dual global wolfsburg GNS-X VLF navigation system. We have been experiencing numerous sensor miscompares since may/xx/96 to the present. Maintenance unable to find any discrepancies with either navigation unit. No NOTAMS or center advisories were published concerning station shutdowns. We come to find out, on our own, that the military has shut down annapolis and reassigned its frequency to hawaii. Numerous other operators are complaining of navigation anomalies also. There needs to be proper notification through FSS or center concerning these shutdowns. Callback conversation with reporter revealed the following information: reporter states that his company has talked with just about everyone they can to determine the problem. Naval liaison in washington, dc, was amazed to hear that the station had been shut down with no notification to anyone. The local FSDO was not aware of the shutdown. The manufacturer was not aware of the shutdown. Reporter finally learned about it from an avionics service center. Military personnel who have been contacted do not see a problem since it is a military installation and they can shut it down any time they want to without notifying anyone. Reporter says that one flight going to new york had to go inshore because this shutdown and reassignment of the frequency totally disrupted the geometry of the signals. He feels it is a definite hazard to safety of flight and that information regarding the change should be disseminated as rapidly as possible.

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Original NASA ASRS Text

Title: SHUTDOWN OF MIL OMEGA VLF STATION AND REASSIGNMENT OF FREQ TO HAWAII CREATES NAV PROB WITH OMEGA VLF EQUIP.

Narrative: ACFT IS EQUIPPED WITH DUAL GLOBAL WOLFSBURG GNS-X VLF NAV SYS. WE HAVE BEEN EXPERIENCING NUMEROUS SENSOR MISCOMPARES SINCE MAY/XX/96 TO THE PRESENT. MAINT UNABLE TO FIND ANY DISCREPANCIES WITH EITHER NAV UNIT. NO NOTAMS OR CTR ADVISORIES WERE PUBLISHED CONCERNING STATION SHUTDOWNS. WE COME TO FIND OUT, ON OUR OWN, THAT THE MIL HAS SHUT DOWN ANNAPOLIS AND REASSIGNED ITS FREQ TO HAWAII. NUMEROUS OTHER OPERATORS ARE COMPLAINING OF NAV ANOMALIES ALSO. THERE NEEDS TO BE PROPER NOTIFICATION THROUGH FSS OR CTR CONCERNING THESE SHUTDOWNS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATES THAT HIS COMPANY HAS TALKED WITH JUST ABOUT EVERYONE THEY CAN TO DETERMINE THE PROB. NAVAL LIAISON IN WASHINGTON, DC, WAS AMAZED TO HEAR THAT THE STATION HAD BEEN SHUT DOWN WITH NO NOTIFICATION TO ANYONE. THE LCL FSDO WAS NOT AWARE OF THE SHUTDOWN. THE MANUFACTURER WAS NOT AWARE OF THE SHUTDOWN. RPTR FINALLY LEARNED ABOUT IT FROM AN AVIONICS SVC CTR. MIL PERSONNEL WHO HAVE BEEN CONTACTED DO NOT SEE A PROB SINCE IT IS A MIL INSTALLATION AND THEY CAN SHUT IT DOWN ANY TIME THEY WANT TO WITHOUT NOTIFYING ANYONE. RPTR SAYS THAT ONE FLT GOING TO NEW YORK HAD TO GO INSHORE BECAUSE THIS SHUTDOWN AND REASSIGNMENT OF THE FREQ TOTALLY DISRUPTED THE GEOMETRY OF THE SIGNALS. HE FEELS IT IS A DEFINITE HAZARD TO SAFETY OF FLT AND THAT INFO REGARDING THE CHANGE SHOULD BE DISSEMINATED AS RAPIDLY AS POSSIBLE.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.