Narrative:

While lined up to land on runway 4R at ord, clearance was given to descend to 8000 ft by degan intersection. We missed the restr and continued descent for westn intersection at 5000 ft. Due to a number of problems, we also missed that crossing. ATC called us to notify us of altitude deviation which we then corrected to 5000 ft to cross westn at 5000 ft. All other restrs on approach were met. The main cause of this deviation was attributed to distrs in cockpit caused by nuisance maintenance cautions which distraction both crew members during descent. We were given a caution for a pack failure (new problem) and another for a high pressure bleed valve failure. Descending with power to idle deprived the system of sufficient bleed air to operate normally. Once cleared, the cautions kept recurring. This distraction the crew once again. The first officer was flying the airplane while I (captain) worked the problems and talked on the radios. In addition, adding to the problem, the first officer was using DME off the wrong NAVAID which lured him into descending too soon and, therefore, busting altitude. We finally abandoned the cautions which kept coming up and flew the airplane. In retrospect, we should have abandoned the approach since we were still a good distance from the airport and taken care of our maintenance problem somewhere other than on approach.

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Original NASA ASRS Text

Title: AN LGT ACFT ON APCH DEVIATED FROM THE ASSIGNED ALT WHEN THE FLC WAS DISTR BY SEVERAL SYS MALFUNCTIONS.

Narrative: WHILE LINED UP TO LAND ON RWY 4R AT ORD, CLRNC WAS GIVEN TO DSND TO 8000 FT BY DEGAN INTXN. WE MISSED THE RESTR AND CONTINUED DSCNT FOR WESTN INTXN AT 5000 FT. DUE TO A NUMBER OF PROBS, WE ALSO MISSED THAT XING. ATC CALLED US TO NOTIFY US OF ALTDEV WHICH WE THEN CORRECTED TO 5000 FT TO CROSS WESTN AT 5000 FT. ALL OTHER RESTRS ON APCH WERE MET. THE MAIN CAUSE OF THIS DEV WAS ATTRIBUTED TO DISTRS IN COCKPIT CAUSED BY NUISANCE MAINT CAUTIONS WHICH DISTR BOTH CREW MEMBERS DURING DSCNT. WE WERE GIVEN A CAUTION FOR A PACK FAILURE (NEW PROB) AND ANOTHER FOR A HIGH PRESSURE BLEED VALVE FAILURE. DSNDING WITH PWR TO IDLE DEPRIVED THE SYS OF SUFFICIENT BLEED AIR TO OPERATE NORMALLY. ONCE CLRED, THE CAUTIONS KEPT RECURRING. THIS DISTR THE CREW ONCE AGAIN. THE FO WAS FLYING THE AIRPLANE WHILE I (CAPT) WORKED THE PROBS AND TALKED ON THE RADIOS. IN ADDITION, ADDING TO THE PROB, THE FO WAS USING DME OFF THE WRONG NAVAID WHICH LURED HIM INTO DSNDING TOO SOON AND, THEREFORE, BUSTING ALT. WE FINALLY ABANDONED THE CAUTIONS WHICH KEPT COMING UP AND FLEW THE AIRPLANE. IN RETROSPECT, WE SHOULD HAVE ABANDONED THE APCH SINCE WE WERE STILL A GOOD DISTANCE FROM THE ARPT AND TAKEN CARE OF OUR MAINT PROB SOMEWHERE OTHER THAN ON APCH.

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.