Narrative:

Descending into ind for visual approach, we were initially cleared to 12000 ft. Subsequent clearance to 10000 ft. I was on the PA giving the passenger final destination WX and thank you. First officer receiving operational experience with accumulated 8 hours in MD80. First officer said he armed altitude warning indicator when cleared from 12000 ft to 10000 ft. As I was hanging up the public address, I noticed aircraft descending through 9750 ft. I immediately pushed 'altitude hold' button on digital flight guidance system to stop descent. Aircraft descended to approximately 9600 ft before returning to 9700 ft. We then climbed back to 10000 ft and approach then gave us a descent clearance to 4000 ft. Human factors -- complacency on my part -- the first officer was doing great, up to that time. I also should have prioritized my passenger announcement to earlier in the descent. This would have left me completely free to monitor the first officer during critical phase of flight.

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Original NASA ASRS Text

Title: ALT BUST WITH TRAINING IN PROGRESS IN AN MD80 TYPE ACFT. ACFT IN AN ALTDEV ALT OVERSHOT WHEN PF, FO, FAILED TO USE THE ALT CAPTURE ON THE AUTOPLT. ALT ALERT DID NOT GO OFF. PIC RECOVERED. FLC DEV.

Narrative: DSNDING INTO IND FOR VISUAL APCH, WE WERE INITIALLY CLRED TO 12000 FT. SUBSEQUENT CLRNC TO 10000 FT. I WAS ON THE PA GIVING THE PAX FINAL DEST WX AND THANK YOU. FO RECEIVING OPERATIONAL EXPERIENCE WITH ACCUMULATED 8 HRS IN MD80. FO SAID HE ARMED ALT WARNING INDICATOR WHEN CLRED FROM 12000 FT TO 10000 FT. AS I WAS HANGING UP THE PUBLIC ADDRESS, I NOTICED ACFT DSNDING THROUGH 9750 FT. I IMMEDIATELY PUSHED 'ALT HOLD' BUTTON ON DIGITAL FLT GUIDANCE SYS TO STOP DSCNT. ACFT DSNDED TO APPROX 9600 FT BEFORE RETURNING TO 9700 FT. WE THEN CLBED BACK TO 10000 FT AND APCH THEN GAVE US A DSCNT CLRNC TO 4000 FT. HUMAN FACTORS -- COMPLACENCY ON MY PART -- THE FO WAS DOING GREAT, UP TO THAT TIME. I ALSO SHOULD HAVE PRIORITIZED MY PAX ANNOUNCEMENT TO EARLIER IN THE DSCNT. THIS WOULD HAVE LEFT ME COMPLETELY FREE TO MONITOR THE FO DURING CRITICAL PHASE OF FLT.

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.