A320
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 60; Flight Crew Total 13000; Flight Crew Type 4000
Troubleshooting
Aircraft Equipment Problem Less Severe
Flight Crew Became Reoriented; General Maintenance Action
Aircraft; Human Factors; MEL; Procedure
Inbound flight logged 2 items- SYS 1 FAULT DISPLAYED ON UPPER ECAM-BRAKES and AUTOBRAKE FAULT DISPLAYED ON UPPER ECAM SCREEN-BRAKES. Maintenance deferred the first ECAM with MEL 32-42-03 BSCU 1 inoperative. That deferral makes a reference to the autobrake panel mode lights being inoperative and has a note FOR BSCU CHANNEL/SYSTEM 1 INOPERATIVE REFER TO MEL FOR AUTO/BRK PANEL MODE LIGHTS DEFERRAL. Maintenance took that reference and used it to defer the second ECAM listed above (MEL 32-42-04). In my review of the MEL; once on board; I did not question the linking of the second ECAM to the first ECAM MEL; guidance that was made by Maintenance. I ASSUMED that Maintenance had specific guidance that the second ECAM was a result of the loss of BSCU 1 and the autobrake panel lights; nothing more complex that had to be evaluated for compound failures. We complied with all MEL restrictions prior to departure to include verifying that the autobrakes were armed on the wheels SD page. Checking recall prior to departure only brought up the first ECAM. No autobrake ECAM or status messages were present. This furthered my belief that the maintenance issues had been addressed correctly. Taxi; takeoff and initial climb were normal. Nearing FL350 we received the same autobrake fault ECAM received by the first crew. We complied with the Irregular Procedure. We determined that we had lost normal brakes but did have antiskid. Further review of the Flight Manual to include the system resets section made it apparent to me that the autobrakes ECAM; while obviously related to the brake system fault ECAM; was not linked to it as a secondary failure due to the lights failure. We had two separate failures; as did the inbound flight that should have been treated as such. The maintenance dispatch was improper/illegal. Trust but VERIFY everything! Careful verification of maintenance actions could have prevented this.
Illegal dispatch; the aircraft was dispatched with a BSCU channel 1 fault; along with the annunciator lights for the autobrakes inoperative. In fact the autobrakes and the BSCU 1 were written up on the inbound flight and Maintenance interpreted the autobrake fault as just an annunciator light issue. The plane should have been dispatched with an autobrake fault and BSCU channel 1 fault. Enroute we ran the autobrake fault ECAM; contacted Dispatch and Maintenance and continued to destination.
A320 flight crew experiences an autobrake fault in cruise after the fault had been previously written up and diagnosed as an autobrake panel light fault and MELed as such. BSCU 1 was also MELed separately. Flight continues to destination.