Narrative:

Only 1 aircraft on my frequency at this time, so loss of separation not a factor. I had just relieved a controller with all position except clearance delivery combined in the tower when the d-brite(south) went out. There were no alarms only the disappearance of the ARTS and an error message at the bottom of the scope. The radar was operating properly downstairs in the TRACON and was opened as soon as possible. The potential problem here is that if we had been busy and were vectoring for minimum spacing this could've caused an unsafe situation by happening with no warning or alarms. At first I thought I had only lost the ARTS and I realized only after a few mins had passed that I had lost everything. Suggest some visual alarm (i.e., light or flag) be used to show OTS condition.

Google
 

Original NASA ASRS Text

Title: D-BRITE RADAR SCOPE FAILURE IN TWR AT SAT.

Narrative: ONLY 1 ACFT ON MY FREQ AT THIS TIME, SO LOSS OF SEPARATION NOT A FACTOR. I HAD JUST RELIEVED A CTLR WITH ALL POS EXCEPT CLRNC DELIVERY COMBINED IN THE TWR WHEN THE D-BRITE(S) WENT OUT. THERE WERE NO ALARMS ONLY THE DISAPPEARANCE OF THE ARTS AND AN ERROR MESSAGE AT THE BOTTOM OF THE SCOPE. THE RADAR WAS OPERATING PROPERLY DOWNSTAIRS IN THE TRACON AND WAS OPENED ASAP. THE POTENTIAL PROB HERE IS THAT IF WE HAD BEEN BUSY AND WERE VECTORING FOR MINIMUM SPACING THIS COULD'VE CAUSED AN UNSAFE SIT BY HAPPENING WITH NO WARNING OR ALARMS. AT FIRST I THOUGHT I HAD ONLY LOST THE ARTS AND I REALIZED ONLY AFTER A FEW MINS HAD PASSED THAT I HAD LOST EVERYTHING. SUGGEST SOME VISUAL ALARM (I.E., LIGHT OR FLAG) BE USED TO SHOW OTS CONDITION.

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.