Narrative:

We were cleared from 15000 ft to 8000 ft. PF began pointing out sights on the ground below 10000 ft and was listening to the am radio through the ADF and we did not hear the altitude alert tone and descended through 8000 ft to 7000 ft, an altitude we are normally cleared down to. ATC inquired as to our altitude and we then took immediate action and climbed back to 8000 ft. Another aircraft was behind us at 7000 ft at a distance greater than 3 NM as evidenced by our TCASII. Excessive talking and noise during a sterile cockpit situation caused the altitude excursion. In addition, after a normal landing, the aircraft taking off after we landed saw an access door come off the tail section of the aircraft after landing. No passenger or flight attendants heard any unusual noises and a preflight was made before initial departure and noted all latches closed. Apparently a latch was somehow torn loose causing the whole door to give way in the airstream. I would say that a mechanical failure of the door latch caused this. This door was found on the runway.

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Original NASA ASRS Text

Title: ALTDEV ALT OVERSHOT - ACR CREW DSNDS BELOW ASSIGNED ALT WHILE CAPT (FLYING) ACTS AS A TOUR GUIDE AND LISTENS TO THE AM RADIO.

Narrative: WE WERE CLRED FROM 15000 FT TO 8000 FT. PF BEGAN POINTING OUT SIGHTS ON THE GND BELOW 10000 FT AND WAS LISTENING TO THE AM RADIO THROUGH THE ADF AND WE DID NOT HEAR THE ALT ALERT TONE AND DSNDED THROUGH 8000 FT TO 7000 FT, AN ALT WE ARE NORMALLY CLRED DOWN TO. ATC INQUIRED AS TO OUR ALT AND WE THEN TOOK IMMEDIATE ACTION AND CLBED BACK TO 8000 FT. ANOTHER ACFT WAS BEHIND US AT 7000 FT AT A DISTANCE GREATER THAN 3 NM AS EVIDENCED BY OUR TCASII. EXCESSIVE TALKING AND NOISE DURING A STERILE COCKPIT SIT CAUSED THE ALT EXCURSION. IN ADDITION, AFTER A NORMAL LNDG, THE ACFT TAKING OFF AFTER WE LANDED SAW AN ACCESS DOOR COME OFF THE TAIL SECTION OF THE ACFT AFTER LNDG. NO PAX OR FLT ATTENDANTS HEARD ANY UNUSUAL NOISES AND A PREFLT WAS MADE BEFORE INITIAL DEP AND NOTED ALL LATCHES CLOSED. APPARENTLY A LATCH WAS SOMEHOW TORN LOOSE CAUSING THE WHOLE DOOR TO GIVE WAY IN THE AIRSTREAM. I WOULD SAY THAT A MECHANICAL FAILURE OF THE DOOR LATCH CAUSED THIS. THIS DOOR WAS FOUND ON THE RWY.

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.