Narrative:

After takeoff from mry (first officer flying) cleared to intercept big sur 1 arrival to sfo, and 'climb to and maintain 10000 ft.' after PF leveled aircraft at 10000 ft, I turned to get 28L approach plate from my flight bag. This took only a few seconds, however, when my attention returned to the aircraft, we were at 10500 ft and climbing. I immediately returned the aircraft to 10000 ft and returned control to the first officer. Subsequent approach and landing at sfo were uneventful. After landing at sfo, first officer stated that she had been feeling ill before takeoff, that during flight was having trouble concentrating, and was now too ill to continue balance of days flying. She subsequently called in sick and was replaced by a reserve. It is imperative that any crew member inform other crew members of any infirmity before a problem develops.

Google
 

Original NASA ASRS Text

Title: ALTDEV ALT OVERSHOT IN CLB.

Narrative: AFTER TKOF FROM MRY (FO FLYING) CLRED TO INTERCEPT BIG SUR 1 ARR TO SFO, AND 'CLB TO AND MAINTAIN 10000 FT.' AFTER PF LEVELED ACFT AT 10000 FT, I TURNED TO GET 28L APCH PLATE FROM MY FLT BAG. THIS TOOK ONLY A FEW SECONDS, HOWEVER, WHEN MY ATTN RETURNED TO THE ACFT, WE WERE AT 10500 FT AND CLBING. I IMMEDIATELY RETURNED THE ACFT TO 10000 FT AND RETURNED CTL TO THE FO. SUBSEQUENT APCH AND LNDG AT SFO WERE UNEVENTFUL. AFTER LNDG AT SFO, FO STATED THAT SHE HAD BEEN FEELING ILL BEFORE TKOF, THAT DURING FLT WAS HAVING TROUBLE CONCENTRATING, AND WAS NOW TOO ILL TO CONTINUE BAL OF DAYS FLYING. SHE SUBSEQUENTLY CALLED IN SICK AND WAS REPLACED BY A RESERVE. IT IS IMPERATIVE THAT ANY CREW MEMBER INFORM OTHER CREW MEMBERS OF ANY INFIRMITY BEFORE A PROBLEM DEVELOPS.

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.