Narrative:

Problem with brake system/possible bscu issue. Aircraft had an MEL for the autobrake system inoperative. No action items required; except for special consideration listed when doing the takeoff confign test during taxi out (prior to takeoff). Routine flight until we extended the landing gear on runway 25L approach into ZZZ. We received a class I ECAM for autobrake system inoperative. This was expected due to the installed MEL. However; the lower ECAM status page showed the normal brake system under 'inoperative system.' after a quick discussion with my first officer; we told ZZZ tower that we needed to go around to evaluate a maintenance issue. There was no reason for our normal brake system to be inoperative; so I did not feel comfortable continuing from that point. We were somewhere between 2500-3000 ft MSL when commencing the go around. Since we received the brake fault(south) upon selecting the landing gear down; we decided to leave it down. We didn't know what was going on with the brake system and didn't want to risk losing another component. Fuel was not a factor at this point. We had departed ZZZ1 with 1500 pounds contingency fuel; plus about 400 pounds more than the release minimum fuel. ATC vectored us on a very wide traffic pattern. Other than some minor confusion on a heading assignment; everything progressed smoothly. The first officer updated the passenger and flight attendants with a PA and then reached maintenance control on VHF2. In the meantime; our ECAM system pages showed all hydraulics normal and alternate brakes operational (green on the 'wheels' page). Maintenance control agreed that there was another issue with the brake system because MEL'ed autobrakes should not in itself affect normal braking. Maintenance control offered that I exercise my emergency authority/authorized and cycle the north/west and antiskid switch to see if normal braking could be restored. After discussing it with my first officer; I decided against doing this. Since I knew that the alternate brakes were operational; I didn't want to risk any further malfunctions. We were extremely light (approximately 111000 pounds after go around). We asked ATC for the longest runway. Wind was less than 10 KTS. After careful evaluation; we decided to treat it as a normal landing using the alternate brake system. I made a PA alerting the passenger and flight attendants that our primary braking system was inoperative; but that our 2 back-ups (alternate and accumulator) were fully functional and that we planned an 'uneventful' landing safely in approximately 10 mins.

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Original NASA ASRS Text

Title: AN A319 PILOT RECEIVES A BSCU ECAM WARNING AFTER LOWERING THE LANDING GEAR. THE NORMAL AND ALT BRAKES APPEARED NORMAL. A NORMAL LANDING WAS MADE.

Narrative: PROB WITH BRAKE SYS/POSSIBLE BSCU ISSUE. ACFT HAD AN MEL FOR THE AUTOBRAKE SYS INOP. NO ACTION ITEMS REQUIRED; EXCEPT FOR SPECIAL CONSIDERATION LISTED WHEN DOING THE TKOF CONFIGN TEST DURING TAXI OUT (PRIOR TO TKOF). ROUTINE FLT UNTIL WE EXTENDED THE LNDG GEAR ON RWY 25L APCH INTO ZZZ. WE RECEIVED A CLASS I ECAM FOR AUTOBRAKE SYS INOP. THIS WAS EXPECTED DUE TO THE INSTALLED MEL. HOWEVER; THE LOWER ECAM STATUS PAGE SHOWED THE NORMAL BRAKE SYS UNDER 'INOP SYS.' AFTER A QUICK DISCUSSION WITH MY FO; WE TOLD ZZZ TWR THAT WE NEEDED TO GO AROUND TO EVALUATE A MAINT ISSUE. THERE WAS NO REASON FOR OUR NORMAL BRAKE SYS TO BE INOP; SO I DID NOT FEEL COMFORTABLE CONTINUING FROM THAT POINT. WE WERE SOMEWHERE BTWN 2500-3000 FT MSL WHEN COMMENCING THE GAR. SINCE WE RECEIVED THE BRAKE FAULT(S) UPON SELECTING THE LNDG GEAR DOWN; WE DECIDED TO LEAVE IT DOWN. WE DIDN'T KNOW WHAT WAS GOING ON WITH THE BRAKE SYS AND DIDN'T WANT TO RISK LOSING ANOTHER COMPONENT. FUEL WAS NOT A FACTOR AT THIS POINT. WE HAD DEPARTED ZZZ1 WITH 1500 LBS CONTINGENCY FUEL; PLUS ABOUT 400 LBS MORE THAN THE RELEASE MINIMUM FUEL. ATC VECTORED US ON A VERY WIDE TFC PATTERN. OTHER THAN SOME MINOR CONFUSION ON A HDG ASSIGNMENT; EVERYTHING PROGRESSED SMOOTHLY. THE FO UPDATED THE PAX AND FLT ATTENDANTS WITH A PA AND THEN REACHED MAINT CTL ON VHF2. IN THE MEANTIME; OUR ECAM SYS PAGES SHOWED ALL HYDS NORMAL AND ALTERNATE BRAKES OPERATIONAL (GREEN ON THE 'WHEELS' PAGE). MAINT CTL AGREED THAT THERE WAS ANOTHER ISSUE WITH THE BRAKE SYS BECAUSE MEL'ED AUTOBRAKES SHOULD NOT IN ITSELF AFFECT NORMAL BRAKING. MAINT CTL OFFERED THAT I EXERCISE MY EMER AUTH AND CYCLE THE N/W AND ANTISKID SWITCH TO SEE IF NORMAL BRAKING COULD BE RESTORED. AFTER DISCUSSING IT WITH MY FO; I DECIDED AGAINST DOING THIS. SINCE I KNEW THAT THE ALTERNATE BRAKES WERE OPERATIONAL; I DIDN'T WANT TO RISK ANY FURTHER MALFUNCTIONS. WE WERE EXTREMELY LIGHT (APPROX 111000 LBS AFTER GAR). WE ASKED ATC FOR THE LONGEST RWY. WIND WAS LESS THAN 10 KTS. AFTER CAREFUL EVALUATION; WE DECIDED TO TREAT IT AS A NORMAL LNDG USING THE ALTERNATE BRAKE SYS. I MADE A PA ALERTING THE PAX AND FLT ATTENDANTS THAT OUR PRIMARY BRAKING SYS WAS INOP; BUT THAT OUR 2 BACK-UPS (ALTERNATE AND ACCUMULATOR) WERE FULLY FUNCTIONAL AND THAT WE PLANNED AN 'UNEVENTFUL' LNDG SAFELY IN APPROX 10 MINS.

Data retrieved from NASA's ASRS site as of January 2009 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.