Narrative:

While in descent in a 2-M crew, the captain was off frequency trying to follow company procedure and contact maintenance, while the first officer was handling both communication and the aircraft. ATC advised a heading change and altitude change, and the first officer set in and armed the altitude and heading in the dfgc. The readback was made to ATC and the aircraft made the descent. The captain finally came back to the ATC radio after calling my several times. ATC advised an immediate turn and that we had descended through the altitude and were in conflict with a commuter aircraft. The captain had already seen this aircraft and had changed bank angle to avoid the aircraft. Next, the crew climbed back to the higher altitude. Cause of the altitude deviation was not known other than the altitude did not capture as assigned and the first officer was overloaded with radio communication and aircraft flight management and missed the altitude. This problem is encountered quite often int he medium large transport aircraft this pilot flies at this company. The company has had many problems in this dfgc system in this area, and is working with the mfr to change the program. Altitude assignments and warnings are easily lost, and the autoplt will not catch the assigned altitude. Both pilots must monitor the system at all times while in flight west/O distraction, especially in a congested TCA. Supplemental information from acn 129590: he said he received clearance of 070 degree heading and 8000'. We were leveling at 7000'. Altitude had not armed.

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Original NASA ASRS Text

Title: ACR MLG ALT DEVIATION OVERSHOT DURING DESCENT CAUSES LESS THAN STANDARD SEPARATION WITH COMMUTER ACFT IN ORD TCA.

Narrative: WHILE IN DSCNT IN A 2-M CREW, THE CAPT WAS OFF FREQ TRYING TO FOLLOW COMPANY PROC AND CONTACT MAINT, WHILE THE F/O WAS HANDLING BOTH COM AND THE ACFT. ATC ADVISED A HDG CHANGE AND ALT CHANGE, AND THE F/O SET IN AND ARMED THE ALT AND HDG IN THE DFGC. THE READBACK WAS MADE TO ATC AND THE ACFT MADE THE DSCNT. THE CAPT FINALLY CAME BACK TO THE ATC RADIO AFTER CALLING MY SEVERAL TIMES. ATC ADVISED AN IMMEDIATE TURN AND THAT WE HAD DSNDED THROUGH THE ALT AND WERE IN CONFLICT WITH A COMMUTER ACFT. THE CAPT HAD ALREADY SEEN THIS ACFT AND HAD CHANGED BANK ANGLE TO AVOID THE ACFT. NEXT, THE CREW CLBED BACK TO THE HIGHER ALT. CAUSE OF THE ALT DEVIATION WAS NOT KNOWN OTHER THAN THE ALT DID NOT CAPTURE AS ASSIGNED AND THE F/O WAS OVERLOADED WITH RADIO COM AND ACFT FLT MGMNT AND MISSED THE ALT. THIS PROB IS ENCOUNTERED QUITE OFTEN INT HE MLG ACFT THIS PLT FLIES AT THIS COMPANY. THE COMPANY HAS HAD MANY PROBS IN THIS DFGC SYS IN THIS AREA, AND IS WORKING WITH THE MFR TO CHANGE THE PROGRAM. ALT ASSIGNMENTS AND WARNINGS ARE EASILY LOST, AND THE AUTOPLT WILL NOT CATCH THE ASSIGNED ALT. BOTH PLTS MUST MONITOR THE SYS AT ALL TIMES WHILE IN FLT W/O DISTR, ESPECIALLY IN A CONGESTED TCA. SUPPLEMENTAL INFO FROM ACN 129590: HE SAID HE RECEIVED CLRNC OF 070 DEG HDG AND 8000'. WE WERE LEVELING AT 7000'. ALT HAD NOT ARMED.

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.