Narrative:

Boston TRACON (A90) went into cenrap at XA26Z with the agreement that maintenance would be completed by XB00Z. In cenrap, the separation requirements are increased to en route spacing requirements or visual separation can be applied. The radar (ASR-9) was needed by XB00Z in order to handle the influx of traffic anticipated at that time of day. A 10 mi in trail restriction was issued by flow control for the cenrap operation. At XB00Z, with traffic building, maintenance personnel could not be contacted. At XB03Z, a 20 mi in trail flow restriction was issued with traffic for most sectors moderate to heavy. At XB07Z the ASR-9 was returned without primary radar. Using beacon targets (secondary radar), which eliminated the en route spacing requirements, cenrap was shut down. Shortly after the cenrap was shut down all of the data blocks, except those in handoff status, dropped off the scopes into the coast lists. This happened on all scopes at a time when a few sectors were busy with heavy traffic on vectors. This created undue workload and increased the possibility of operational and/or midair collisions immeasurably. It took about 1 min working without ARTS data blocks, using only secondary radar, in heavy traffic conditions before cenrap was reinstated. The ASR-9 was returned to service at XB23Z. Solution to problem: since the nature of maintenance is unreliable, future shutdowns of the ASR-9 radar should occur only during low traffic times and, our procedures and flow should not be predicated on the radar coming back at a certain time. If maintenance personnel cannot comply with restrictions, they should advise in time to allow alternate procedures to be used.

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Original NASA ASRS Text

Title: CTLR COMPLAINS THAT MAINT TOOK A PORTION OF THE RADAR AND DID NOT RETURN IT AT THE PREDETERMINED TIME. HVY TFC FLOW RESULTED IN INCREASED CTLR WORKLOAD.

Narrative: BOSTON TRACON (A90) WENT INTO CENRAP AT XA26Z WITH THE AGREEMENT THAT MAINT WOULD BE COMPLETED BY XB00Z. IN CENRAP, THE SEPARATION REQUIREMENTS ARE INCREASED TO ENRTE SPACING REQUIREMENTS OR VISUAL SEPARATION CAN BE APPLIED. THE RADAR (ASR-9) WAS NEEDED BY XB00Z IN ORDER TO HANDLE THE INFLUX OF TFC ANTICIPATED AT THAT TIME OF DAY. A 10 MI IN TRAIL RESTRICTION WAS ISSUED BY FLOW CTL FOR THE CENRAP OP. AT XB00Z, WITH TFC BUILDING, MAINT PERSONNEL COULD NOT BE CONTACTED. AT XB03Z, A 20 MI IN TRAIL FLOW RESTRICTION WAS ISSUED WITH TFC FOR MOST SECTORS MODERATE TO HVY. AT XB07Z THE ASR-9 WAS RETURNED WITHOUT PRIMARY RADAR. USING BEACON TARGETS (SECONDARY RADAR), WHICH ELIMINATED THE ENRTE SPACING REQUIREMENTS, CENRAP WAS SHUT DOWN. SHORTLY AFTER THE CENRAP WAS SHUT DOWN ALL OF THE DATA BLOCKS, EXCEPT THOSE IN HDOF STATUS, DROPPED OFF THE SCOPES INTO THE COAST LISTS. THIS HAPPENED ON ALL SCOPES AT A TIME WHEN A FEW SECTORS WERE BUSY WITH HVY TFC ON VECTORS. THIS CREATED UNDUE WORKLOAD AND INCREASED THE POSSIBILITY OF OPERATIONAL AND/OR MIDAIR COLLISIONS IMMEASURABLY. IT TOOK ABOUT 1 MIN WORKING WITHOUT ARTS DATA BLOCKS, USING ONLY SECONDARY RADAR, IN HVY TFC CONDITIONS BEFORE CENRAP WAS REINSTATED. THE ASR-9 WAS RETURNED TO SVC AT XB23Z. SOLUTION TO PROB: SINCE THE NATURE OF MAINT IS UNRELIABLE, FUTURE SHUTDOWNS OF THE ASR-9 RADAR SHOULD OCCUR ONLY DURING LOW TFC TIMES AND, OUR PROCS AND FLOW SHOULD NOT BE PREDICATED ON THE RADAR COMING BACK AT A CERTAIN TIME. IF MAINT PERSONNEL CANNOT COMPLY WITH RESTRICTIONS, THEY SHOULD ADVISE IN TIME TO ALLOW ALTERNATE PROCS TO BE USED.

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.