Narrative:

First officer flying on autoplt, descending from FL370 to 330, landing ord. I was looking over arrival routes and runways when I heard autoplt disengage. Looked at altitude, FL325. First officer with very positive back pressure manually leveled the aircraft at FL330. Might be a lack of understanding of the system; i.e., moving pitch control wheel while in the capture mode, which disengages autocapture and hold. Also there may have been a little complacency. Not checking automatic functions with raw data. My observations while the first officer is flying is a lack of responsibility for his actions. Make the first officer answer for his actions. Supplemental information from acn 135029: captain failed to arm the altitude descent window. I feel he is still used to flying the widebody transport a, where you don't have to pull out on the alert knob, but on the widebody transport B you have to select the new altitude and pull out on the knob to arm it. Crew attention was diverted and no altitude warning sounded, and the crew had to make an abrupt level off. 1 passenger was injured about this time in the flight. Paramedics met the aircraft. Supplemental information from acn 134889: I was at the F/east table copying ATIS information and accomplishing company required paperwork in preparation for our descent into ord. As I was writing, I felt a slight 'G' sensation. It simply felt like a momentary bump of turbulence. When I turned forward to hand the pilots the paperwork, the captain was making a comment about the bump, but I missed it because I was still monitoring ATIS on my headset. Later I was informed that the autoplt had failed to capture the en route descent altitude. Our pilots detected the failure and returned the aircraft to FL330.

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Original NASA ASRS Text

Title: ACR WDB OVERSHOOTS ALT IN DESCENT, ABRUPT PULL-UP CAUSES MINOR INJURY TO A PASSENGER.

Narrative: F/O FLYING ON AUTOPLT, DSNDING FROM FL370 TO 330, LNDG ORD. I WAS LOOKING OVER ARR ROUTES AND RWYS WHEN I HEARD AUTOPLT DISENGAGE. LOOKED AT ALT, FL325. F/O WITH VERY POSITIVE BACK PRESSURE MANUALLY LEVELED THE ACFT AT FL330. MIGHT BE A LACK OF UNDERSTANDING OF THE SYS; I.E., MOVING PITCH CTL WHEEL WHILE IN THE CAPTURE MODE, WHICH DISENGAGES AUTOCAPTURE AND HOLD. ALSO THERE MAY HAVE BEEN A LITTLE COMPLACENCY. NOT CHKING AUTO FUNCTIONS WITH RAW DATA. MY OBSERVATIONS WHILE THE F/O IS FLYING IS A LACK OF RESPONSIBILITY FOR HIS ACTIONS. MAKE THE F/O ANSWER FOR HIS ACTIONS. SUPPLEMENTAL INFO FROM ACN 135029: CAPT FAILED TO ARM THE ALT DSCNT WINDOW. I FEEL HE IS STILL USED TO FLYING THE WDB A, WHERE YOU DON'T HAVE TO PULL OUT ON THE ALERT KNOB, BUT ON THE WDB B YOU HAVE TO SELECT THE NEW ALT AND PULL OUT ON THE KNOB TO ARM IT. CREW ATTN WAS DIVERTED AND NO ALT WARNING SOUNDED, AND THE CREW HAD TO MAKE AN ABRUPT LEVEL OFF. 1 PAX WAS INJURED ABOUT THIS TIME IN THE FLT. PARAMEDICS MET THE ACFT. SUPPLEMENTAL INFO FROM ACN 134889: I WAS AT THE F/E TABLE COPYING ATIS INFO AND ACCOMPLISHING COMPANY REQUIRED PAPERWORK IN PREPARATION FOR OUR DSCNT INTO ORD. AS I WAS WRITING, I FELT A SLIGHT 'G' SENSATION. IT SIMPLY FELT LIKE A MOMENTARY BUMP OF TURB. WHEN I TURNED FORWARD TO HAND THE PLTS THE PAPERWORK, THE CAPT WAS MAKING A COMMENT ABOUT THE BUMP, BUT I MISSED IT BECAUSE I WAS STILL MONITORING ATIS ON MY HEADSET. LATER I WAS INFORMED THAT THE AUTOPLT HAD FAILED TO CAPTURE THE ENRTE DSCNT ALT. OUR PLTS DETECTED THE FAILURE AND RETURNED THE ACFT TO FL330.

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.