Date: 201305
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Light: Daylight
Aircraft: A321
Operator: Air Carrier
Operating under: Part 121
Flight phase: Parked
Aircraft component: Brake System
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: First Officer
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness; Confusion; Communication Breakdown; Troubleshooting
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: Aircraft In Service At Gate
Result: General Flight Cancelled / Delayed; General Maintenance Action
Contributing factors: Aircraft; Company Policy; Human Factors; MEL; Procedure
Primary problem: Company Policy

Narrative: We flew the same A321 from ZZZ to ZZZ1 and later from ZZZ1 to ZZZ2. When we picked up the aircraft in ZZZ for the XA:00am departure to ZZZ1; the Autobrakes were on MEL. The flight to ZZZ1 was otherwise uneventful; except that when we reached the gate in ZZZ1 (after landing on Runway 23 in ZZZ1); the Right Inboard brake temperature was 545 degrees C (Centigrade) and the Right Outboard was 35 degrees C. Both left Main [Gear tires] were around 290 degrees C.  We notified Maintenance of the discrepancy and were eventually informed this aircraft had been having brake problems for over 10 days; and the Brake Steering Control Unit (BSCU) computers had already been changed.  After the local Maintenance conferred with Maintenmance Control; they decided to bleed the brake system. Having worked on automotive brake systems; I strongly suspected this would be ineffective; since brakes with air in the lines tend to brake weakly; but do brake some. The right outboard temperature (approximately ambient; and verified by Maintenance with a radiant thermometer) indicated the brake was completely ineffective (thus the unusually high brake temperature on the Right inboard; which was compensating for the lack of outboard braking).  However; I acknowledge that I am not a qualified aircraft Mechanic. In addition; as a First Officer (F/O); my ability to influence Maintenance actions are limited to mere verbal influence via discussion with the Maintenance technicians and the C/O; unless I feel I must exercise the 'nuclear option' of declaring my unwillingness to fly in a given situation. The Captain was comfortable with Maintenance's explanations that the bleeding procedure was within the normal responses to this malfunction. I knew that we were taking off and landing in excellent weather and on very long runways; so I elected to accept the aircraft and fly to ZZZ3. On the other hand; I was highly skeptical that the bleeding of the brakes would successfully fix the problem; and told the Captain that I suspected [brake issue] would again appear upon our arrival in ZZZ3. I was surprised; considering the apparent history of this problem; that we weren't given a spare plane and [that] our aircraft was not taken to the Hangar in ZZZ1 to perform in-depth troubleshooting.  Upon arrival in ZZZ3; after landing on very long runways with a strong headwind; our Left Brake temperatures were around 170 degrees C; the left inboard was 320 degrees (deg.) C and the right inboard was again 35 degrees C (it had only changed from that when it dropped to 30 deg. C in ZZZ1 when we ran the brake fans for the high inboard brake temperature). In ZZZ3; the Maintenance technicians told me the plane had been having brake problems for 30-days (rather than the 15 [days] I had been told in ZZZ1). I told them what I had been told in ZZZ1 and our experience with the problem. Eventually; since we were beginning to run out of crew duty day; we were told to take the aircraft that had arrived for the next ZZZ3-ZZZ1 flight; and that [Flight] crew was assigned our very delayed flight; since they had more duty time available. Apparently; this aircraft has somehow been allowed to fly revenue flights for either 15 or 30 days with an existing brake system malfunction. I wonder if the right outboard brake has been inoperative for weeks. While I understand that we do have the brake on the other tire; and it was clearly working hard; it appears to me that no one has recognized that this aircraft needs to be taken out of service and VERIFIABLY FIXED. I believe there is a safety PROCESS problem (perhaps influenced by a culture of operational imperative over safety consciousness) that is reflected in this problem continuing for so long. Believe it or not; brakes are actually a pretty important system on a plane; and had this plane been required to make a maximum performance Rejected Takeoff (RTO) on a wet runway at some point; I would not have been surprised to see it depart the runway; at great risk to the people on board.  Some process needs to be developed (or repaired) to identify recurring major system faults; and to take those aircraft out of service until the plane can be VERIFIED to have been fixed. This is a DIFFICULT challenge; but an IMPORTANT one. It would require effective communication between the maintenance and flight operations departments. However; it may prevent a horrible accident; which none of us want to see again. Flight delay.

Callback: Reporter stated from what he remembers; the Autobrakes MEL was a Category 'C' MEL with a ten day repair window. The Brake Steering Control Unit (BSCU) was replaced again and a recent check of the aircraft's history indicates no further problems after several flights.



Synopsis: A pilot reports about an A321 aircraft that somehow had been allowed to fly revenue flights between 15 and 30 days with an existing right-hand Outboard Brake not functioning and the Autobrakes on MEL.  Replacing the Brake Steering Control Unit (BSCU) did not correct the discrepancy; deferral had continued. Concerns also raised about chronic major system faults not being fixed.