An MD80 first officer reported descending below assigned altitude while attempting to level off; han...

Narrative:

Very busy descent during arrival. There was a build-up in front of us as we started our descent. Center could not let us turn until traffic was clear behind us. He gave that traffic a turn off course and started us out of FL340 to level at FL240. During descent we were asked to please expedite to FL240 to gain separation from traffic. I complied with the instruction and started a 3500 FPM descent. Shortly thereafter we were allowed to turn to avoid the build-up between us and the next fix. As the aircraft started to level it was still on autopilot. From my experience on the MD80 this seemed like one of those situations it might not stop the level off in time so I disconnected the autopilot and started to hand-fly the level off. As luck would have it this is when we also were handing trays back to the #1 flight attendant. As I hand flew and handed a tray back; I allowed the aircraft to descend below our level off altitude of FL240. By the time I turned around we were at FL238. I quickly corrected but not before we were approximately 250 ft low. There was no conflict with any other aircraft as far as I know. Classic distraction and poor prioritization on my part.

Original NASA ASRS Text

Title: An MD80 First Officer reported descending below assigned altitude while attempting to level off; hand fly; and pass a food tray to the Flight Attendant.

Narrative: Very busy descent during arrival. There was a build-up in front of us as we started our descent. Center could not let us turn until traffic was clear behind us. He gave that traffic a turn off course and started us out of FL340 to level at FL240. During descent we were asked to please expedite to FL240 to gain separation from traffic. I complied with the instruction and started a 3500 FPM descent. Shortly thereafter we were allowed to turn to avoid the build-up between us and the next fix. As the aircraft started to level it was still on autopilot. From my experience on the MD80 this seemed like one of those situations it might not stop the level off in time so I disconnected the autopilot and started to hand-fly the level off. As luck would have it this is when we also were handing trays back to the #1 Flight Attendant. As I hand flew and handed a tray back; I allowed the aircraft to descend below our level off altitude of FL240. By the time I turned around we were at FL238. I quickly corrected but not before we were approximately 250 FT low. There was no conflict with any other aircraft as far as I know. Classic distraction and poor prioritization on my part.

Data retrieved from NASA's ASRS site as of April 2012 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.

Attributes
ACN	850337
Time
Date	200908
Local Time Of Day	1201-1800
Place
Locale Reference	DFW.Airport
State Reference	TX
Environment
Light	Daylight
Aircraft 1
Make Model Name	MD-80 Series (DC-9-80) Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Descent
Flight Plan	IFR
Person 1
Function	First Officer Pilot Flying
Events
Anomaly	Deviation - Altitude Overshoot Deviation - Procedural Clearance Inflight Event / Encounter Weather / Turbulence

An MD80 first officer reported descending below assigned altitude while attempting to level off; hand fly; and pass a food tray to the flight attendant.