Narrative:

Flight arrived after a normal flight. On gate arrival the aircraft was switched to external power from a portable (ie; diesel/jet-a engine driven) gpu. While preparing for departure of flight; an advisory message indicating that digital acquisition unit #2 'B' had failed was observed on the EICAS. Aom procedures for the EICAS message instructed only to contact maintenance for dispatchability analysis. I contacted maintenance directly by telephone and advised them of the message. Maintenance requested that I power down the aircraft completely and then power the aircraft back up using only internal ship's power. After a 3 min shutdown period the aircraft was re-energized as instructed by maintenance. After the system was back up; the digital acquisition unit #2 'B' message was cleared and all aircraft system appeared to be functioning normally. I again called maintenance and advised them of the situation. I was informed that since all was normal the aircraft was satisfactory to operate flight. I advised maintenance that I had entered all of the crew's actions related to the EICAS message and the EICAS message in the logbook. I was then advised to make an information to maintenance entry. I did this by directly referring to the example including the maintenance controller's employee number that he had provided me. Flight operated completely normally until about 15 mins prior to landing at which time the same EICAS advisory message was again presented on the EICAS. An additional logbook entry was made after gate are following the information to maintenance entry. I and the rest of the crew were a short time later assigned to a different aircraft.

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Original NASA ASRS Text

Title: AN EMB145 ON ARR AT GATE GND PWR WAS SWITCHED TO AIRPLANE. GOT EICAS MESSAGE 'DIGITAL ACQUISITION UNIT 2B FAILED.' PWRED DOWN AIRPLANE WARNING DISAPPEARED. WARNING CLRED UNTIL 15 MINS FROM NEXT STATION. ADDED NEW LOGBOOK ITEM.

Narrative: FLT ARRIVED AFTER A NORMAL FLT. ON GATE ARR THE ACFT WAS SWITCHED TO EXTERNAL PWR FROM A PORTABLE (IE; DIESEL/JET-A ENG DRIVEN) GPU. WHILE PREPARING FOR DEP OF FLT; AN ADVISORY MESSAGE INDICATING THAT DIGITAL ACQUISITION UNIT #2 'B' HAD FAILED WAS OBSERVED ON THE EICAS. AOM PROCS FOR THE EICAS MESSAGE INSTRUCTED ONLY TO CONTACT MAINT FOR DISPATCHABILITY ANALYSIS. I CONTACTED MAINT DIRECTLY BY TELEPHONE AND ADVISED THEM OF THE MESSAGE. MAINT REQUESTED THAT I PWR DOWN THE ACFT COMPLETELY AND THEN PWR THE ACFT BACK UP USING ONLY INTERNAL SHIP'S PWR. AFTER A 3 MIN SHUTDOWN PERIOD THE ACFT WAS RE-ENERGIZED AS INSTRUCTED BY MAINT. AFTER THE SYS WAS BACK UP; THE DIGITAL ACQUISITION UNIT #2 'B' MESSAGE WAS CLRED AND ALL ACFT SYS APPEARED TO BE FUNCTIONING NORMALLY. I AGAIN CALLED MAINT AND ADVISED THEM OF THE SIT. I WAS INFORMED THAT SINCE ALL WAS NORMAL THE ACFT WAS SATISFACTORY TO OPERATE FLT. I ADVISED MAINT THAT I HAD ENTERED ALL OF THE CREW'S ACTIONS RELATED TO THE EICAS MESSAGE AND THE EICAS MESSAGE IN THE LOGBOOK. I WAS THEN ADVISED TO MAKE AN INFO TO MAINT ENTRY. I DID THIS BY DIRECTLY REFERRING TO THE EXAMPLE INCLUDING THE MAINT CTLR'S EMPLOYEE NUMBER THAT HE HAD PROVIDED ME. FLT OPERATED COMPLETELY NORMALLY UNTIL ABOUT 15 MINS PRIOR TO LNDG AT WHICH TIME THE SAME EICAS ADVISORY MESSAGE WAS AGAIN PRESENTED ON THE EICAS. AN ADDITIONAL LOGBOOK ENTRY WAS MADE AFTER GATE ARE FOLLOWING THE INFO TO MAINT ENTRY. I AND THE REST OF THE CREW WERE A SHORT TIME LATER ASSIGNED TO A DIFFERENT ACFT.

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.