Narrative:

Received aircraft in abe with the ACARS screen blank. Consulted MEL and determined we could go with it inoperative and write it up in abe. We (captain and myself) also observed we had no DME signal, which we attributed to the VOR being notamed off the air. Once airborne it was apparent that we had, in fact, lost both DME receivers. We also observed the oil temperature gauge go to full cold off scale and the chime system circuit breaker popped. (We were informed that the chime system was inoperative by the flight attendants.) we contacted maintenance control and were subsequently delayed for +8 hours in mdt. It is my opinion that a bad power source in abe or a bad gcu in aircraft (had history of electrical problems) caused these failures. The lesson to be learned here is that one must exercise vigilance when dealing with multiple failures of unrelated components and keep the #1 priority in focus: 'fly the aircraft first.' callback conversation with reporter revealed the following information: the reporter stated the aircraft was a B737-200 and when the preflight check started in the morning several systems were inoperative. The reporter said the following systems were inoperative: cabin call chime, both DME systems, and one engine oil temperature indicator. The reporter stated the station ground power unit was suspected of not supplying quality power and the above items were deferred. The reporter said at the next station the maintenance controller, when advised of the inoperative systems, stopped the aircraft for a positive fix. The reporter stated the fix was the replacement of the oil temperature indicator, both DME units, and a call chime. The reporter said a report was sent to the overnight station for an electrical check of the ground power unit used on the aircraft.

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Original NASA ASRS Text

Title: A B737-200 HAD SEVERAL SYSTEMS INOP SUSPECTED TO BE CAUSED BY THE STATION GND PWR UNIT.

Narrative: RECEIVED ACFT IN ABE WITH THE ACARS SCREEN BLANK. CONSULTED MEL AND DETERMINED WE COULD GO WITH IT INOP AND WRITE IT UP IN ABE. WE (CAPT AND MYSELF) ALSO OBSERVED WE HAD NO DME SIGNAL, WHICH WE ATTRIBUTED TO THE VOR BEING NOTAMED OFF THE AIR. ONCE AIRBORNE IT WAS APPARENT THAT WE HAD, IN FACT, LOST BOTH DME RECEIVERS. WE ALSO OBSERVED THE OIL TEMP GAUGE GO TO FULL COLD OFF SCALE AND THE CHIME SYSTEM CIRCUIT BREAKER POPPED. (WE WERE INFORMED THAT THE CHIME SYSTEM WAS INOP BY THE FLT ATTENDANTS.) WE CONTACTED MAINT CTL AND WERE SUBSEQUENTLY DELAYED FOR +8 HOURS IN MDT. IT IS MY OPINION THAT A BAD POWER SOURCE IN ABE OR A BAD GCU IN ACFT (HAD HISTORY OF ELECTRICAL PROBLEMS) CAUSED THESE FAILURES. THE LESSON TO BE LEARNED HERE IS THAT ONE MUST EXERCISE VIGILANCE WHEN DEALING WITH MULTIPLE FAILURES OF UNRELATED COMPONENTS AND KEEP THE #1 PRIORITY IN FOCUS: 'FLY THE ACFT FIRST.' CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE ACFT WAS A B737-200 AND WHEN THE PREFLT CHECK STARTED IN THE MORNING SEVERAL SYSTEMS WERE INOP. THE RPTR SAID THE FOLLOWING SYSTEMS WERE INOP: CABIN CALL CHIME, BOTH DME SYSTEMS, AND ONE ENGINE OIL TEMPERATURE INDICATOR. THE RPTR STATED THE STATION GND PWR UNIT WAS SUSPECTED OF NOT SUPPLYING QUALITY PWR AND THE ABOVE ITEMS WERE DEFERRED. THE RPTR SAID AT THE NEXT STATION THE MAINT CTLR, WHEN ADVISED OF THE INOP SYSTEMS, STOPPED THE ACFT FOR A POSITIVE FIX. THE RPTR STATED THE FIX WAS THE REPLACEMENT OF THE OIL TEMP INDICATOR, BOTH DME UNITS, AND A CALL CHIME. THE RPTR SAID A REPORT WAS SENT TO THE OVERNIGHT STATION FOR AN ELECTRICAL CHECK OF THE GND PWR UNIT USED ON THE ACFT.

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.