Narrative:

On log page X; the pilot wrote that the right air conditioning supply gauge indicated 33 psi and the left gauge indicated 27 psi. Per MD80 maintenance manual; the right indication was out of limits. We decided to replace the right supply pressure indicator and the right transmitter. When we turned the packs on to do an operations check; the r-hand indication was within limits; but now the left pack pressure indication was erratic. I signed off logbook page X as having fixed the r-hand indication problem and created a new logbook entry page Y; stating that the left pack indication was erratic. The airplane was supposed to be at the gate so we were unable to do any further troubleshooting and deferred the problem per MEL 21-3. When the next mechanic addressed the write-up for the left pack pressure indication problem on log page Y; he removed a pressure indicator from the left side that had the same serial number as the pressure indicator that we had; supposedly; installed on the right side. The only thing I can think that could have happened is that my co-worker swapped the indicators from left to right to do some troubleshooting and then forgot to swap them back. So the pressure indicator serial number X that was supposed to go on the right side ended up going on the left side.

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Original NASA ASRS Text

Title: AN MD80 R PACK SUPPLY PRESSURE INDICATION WAS OUT OF LIMITS. TECHNICIANS SWAPPING INDICATORS FOR TROUBLESHOOTING FIXED R INDICATOR. L NOW FAILED. FOUND FAILED INDICATOR FROM R PACK INSTALLED IN L PACK.

Narrative: ON LOG PAGE X; THE PLT WROTE THAT THE R AIR CONDITIONING SUPPLY GAUGE INDICATED 33 PSI AND THE L GAUGE INDICATED 27 PSI. PER MD80 MAINT MANUAL; THE R INDICATION WAS OUT OF LIMITS. WE DECIDED TO REPLACE THE R SUPPLY PRESSURE INDICATOR AND THE R XMITTER. WHEN WE TURNED THE PACKS ON TO DO AN OPS CHK; THE R-HAND INDICATION WAS WITHIN LIMITS; BUT NOW THE L PACK PRESSURE INDICATION WAS ERRATIC. I SIGNED OFF LOGBOOK PAGE X AS HAVING FIXED THE R-HAND INDICATION PROB AND CREATED A NEW LOGBOOK ENTRY PAGE Y; STATING THAT THE L PACK INDICATION WAS ERRATIC. THE AIRPLANE WAS SUPPOSED TO BE AT THE GATE SO WE WERE UNABLE TO DO ANY FURTHER TROUBLESHOOTING AND DEFERRED THE PROB PER MEL 21-3. WHEN THE NEXT MECH ADDRESSED THE WRITE-UP FOR THE L PACK PRESSURE INDICATION PROB ON LOG PAGE Y; HE REMOVED A PRESSURE INDICATOR FROM THE L SIDE THAT HAD THE SAME SERIAL NUMBER AS THE PRESSURE INDICATOR THAT WE HAD; SUPPOSEDLY; INSTALLED ON THE R SIDE. THE ONLY THING I CAN THINK THAT COULD HAVE HAPPENED IS THAT MY CO-WORKER SWAPPED THE INDICATORS FROM L TO R TO DO SOME TROUBLESHOOTING AND THEN FORGOT TO SWAP THEM BACK. SO THE PRESSURE INDICATOR SERIAL NUMBER X THAT WAS SUPPOSED TO GO ON THE R SIDE ENDED UP GOING ON THE L SIDE.

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.