A LEAR 31 FLC EXPERIENCES AN OVERSHOOT OF THEIR ASSIGNED ALT WHEN THE AUTOPLT ALT CAPTURE TRIPS OFF AND DOES NOT CAPTURE FL200 AS EXPECTED.

Narrative

CAPT'S WORK DAY BEGAN AT XX00 AM. THE EVENT OCCURRED AT XY50 PM EST. AFTER A FULL DAY OF WORKING AND 4 1/2 HRS OF DRIVING TO BRADLEY; CT; FROM MT HOLLY; NJ; TO PICK UP THE LEAR 31 FROM MAINT; HE WAS EXHAUSTED. ACFT WAS ON AN IFR FLT PLAN OUT OF BDL IN IMC AND WAS CLRED TO FL200. THE AUTOPLT WAS ENGAGED AND THE ALT SELECT MODE WAS DEPRESSED WITH A LIGHT ILLUMINATING THE SELECTION. UPON REACHING FL200 THE ALT CAPTURE MODE DISENGAGED AND THE AUTOPLT DID NOT COMPLETE THE LEVELOFF AT FL200. AT FL202 THE FO; ANNOUNCED TO THE CAPT THAT THE ACFT WAS NOT RESPONDING VIA THE AUTOPLT COMMAND AND THE ALT WAS INCREASING. THE ACFT WAS CONTINUING TO CLB AS THE CAPT BEGAN A ROUND-OFF AND STARTED TO GAIN CTL OF THE ALT SIT. THE ACFT MAY HAVE MOMENTARILY HIT AN ALT OF FL208. THE CAPT WAS DSNDING THROUGH 20200 FT AND LEVELING OFF AT FL200 AS THE BOSTON CTLR QUESTIONED THE ACFT'S ALT. THE FO RPTED LEVEL AT FL200. THE SIT MAY HAVE BEEN AVOIDED BY BOTH PLTS NOTICING THE MISS OF THE ALT HOLD BY THE AUTOPLT AND BETTER REACTION TIME ON BOTH OF THEIR PARTS. FATIGUE WAS A FACTOR DUE TO THE LONG WORK DAY.