Narrative:

Descended thru clearance altitude while detouring around thunderstorms in the ord terminal area. We were on radar vectors for the airport transiting a hole in a line of WX. Original clearance altitude was descend to 10,000', then changed to 13,000', then cleared to maintain 12,000'. First officer was flying, I was handling radios and WX radar. Chicago approach wanted a turn to the northeast as soon as WX permitted. I was talking to approach (with hand held microphone) and evaluating WX returns on radar scope when altitude alert sounded at 11,700'. I pushed all throttles up and told the first officer to climb to 12,000' immediately. First officer said he thought we were cleared to descend to 10,000', altitude alert was set for 12,000'. Approach control did not mention, or comment, on our altitude excursion. No conflicting traffic was identified. This is a classic case of multiple contributing factors leading to an error. Factors are: crew experience, first officer is relatively new, limited jet time, F/east is brand new, first trip, F/east check airman on board. Communications are a factor in that first officer heard what he expected to hear. Also, right/T with approach because of WX involved extra time and attention. Aircraft was dispatched legally with multiple components placarded inoperative including an AC generator, engine bleed valve, and fuel xfeed valve inoperative. Components increased our workload dramatically. The new /first officer and check airman were totally absorbed with managing systems and were out of the monitor loop. The use of antique hand held mics and placement of WX radar and radar controls results in a heads down position for operating crewman. I found myself in a position of not having enough time to monitor crewman and aircraft systems and aircraft performance. Corrective action would include communications awareness training (what did he really say?). For optimum performance we need more experienced crewmen. We really need improvements in aircraft maintenance (since deregulation maintenance has gone steadily downhill). We need to address the components in cockpit design that result in a 'heads down'.

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Original NASA ASRS Text

Title: ALT DEVIATION ON DESCENT. DISTRACTION OF FLT ENGINEER CHECK AIRMAN ABOARD, DEFERRED MAINTENANCE. ITEMS INOPERATIVE.

Narrative: DESCENDED THRU CLRNC ALT WHILE DETOURING AROUND TSTMS IN THE ORD TERMINAL AREA. WE WERE ON RADAR VECTORS FOR THE ARPT TRANSITING A HOLE IN A LINE OF WX. ORIGINAL CLRNC ALT WAS DSND TO 10,000', THEN CHANGED TO 13,000', THEN CLRED TO MAINTAIN 12,000'. F/O WAS FLYING, I WAS HANDLING RADIOS AND WX RADAR. CHICAGO APCH WANTED A TURN TO THE NE AS SOON AS WX PERMITTED. I WAS TALKING TO APCH (WITH HAND HELD MIC) AND EVALUATING WX RETURNS ON RADAR SCOPE WHEN ALT ALERT SOUNDED AT 11,700'. I PUSHED ALL THROTTLES UP AND TOLD THE F/O TO CLIMB TO 12,000' IMMEDIATELY. F/O SAID HE THOUGHT WE WERE CLRED TO DSND TO 10,000', ALT ALERT WAS SET FOR 12,000'. APCH CTL DID NOT MENTION, OR COMMENT, ON OUR ALT EXCURSION. NO CONFLICTING TFC WAS IDENTIFIED. THIS IS A CLASSIC CASE OF MULTIPLE CONTRIBUTING FACTORS LEADING TO AN ERROR. FACTORS ARE: CREW EXPERIENCE, F/O IS RELATIVELY NEW, LIMITED JET TIME, F/E IS BRAND NEW, FIRST TRIP, F/E CHECK AIRMAN ON BOARD. COMS ARE A FACTOR IN THAT F/O HEARD WHAT HE EXPECTED TO HEAR. ALSO, R/T WITH APCH BECAUSE OF WX INVOLVED EXTRA TIME AND ATTN. ACFT WAS DISPATCHED LEGALLY WITH MULTIPLE COMPONENTS PLACARDED INOPERATIVE INCLUDING AN AC GENERATOR, ENGINE BLEED VALVE, AND FUEL XFEED VALVE INOPERATIVE. COMPONENTS INCREASED OUR WORKLOAD DRAMATICALLY. THE NEW /FO AND CHECK AIRMAN WERE TOTALLY ABSORBED WITH MANAGING SYSTEMS AND WERE OUT OF THE MONITOR LOOP. THE USE OF ANTIQUE HAND HELD MICS AND PLACEMENT OF WX RADAR AND RADAR CONTROLS RESULTS IN A HEADS DOWN POSITION FOR OPERATING CREWMAN. I FOUND MYSELF IN A POSITION OF NOT HAVING ENOUGH TIME TO MONITOR CREWMAN AND ACFT SYSTEMS AND ACFT PERFORMANCE. CORRECTIVE ACTION WOULD INCLUDE COMS AWARENESS TRAINING (WHAT DID HE REALLY SAY?). FOR OPTIMUM PERFORMANCE WE NEED MORE EXPERIENCED CREWMEN. WE REALLY NEED IMPROVEMENTS IN ACFT MAINT (SINCE DEREGULATION MAINT HAS GONE STEADILY DOWNHILL). WE NEED TO ADDRESS THE COMPONENTS IN COCKPIT DESIGN THAT RESULT IN A 'HEADS DOWN'.

Data retrieved from NASA's ASRS site as of August 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.