ALT BUST.

Narrative

ON A SCHEDULED FLT FROM IAD TO EWR; THE AUTOPLT WAS ON; CLBING 1000 FPM WITH THE ALT SELECT ARMED FOR 13000 FT. MY CAPT WAS TELLING ME HOW HE HAS HAD PROBS OVER BWI BECAUSE OF THE DIFFERENCE BTWN THE MOVING MAP DISPLAY AND THE HSI. I GUESS THE CTLRS NOTICE A BIG DIFFERENCE IN DEV BTWN THE MAP MODE AND HSI. AS WE WERE DISCUSSING THIS; WE CLBED THROUGH 12000 FT; THE ALT WARNING HORN AND LIGHT WENT OFF. I CALLED 12000 FT FOR 13000 FT AND THE CAPT CONFIRMED THIS. SINCE WE WERE STILL TALKING; WE DID NOT NOTICE THAT THE AUTOPLT FAILED TO CAPTURE. AT 13300 FT THE ALT HORN AND LIGHT WENT OFF AGAIN. I IMMEDIATELY DISENGAGED THE AUTOPLT AND PITCHED DOWN BUT NOT BEFORE WE REACHED 13500 FT. WE LEVELED AT 13000 FT AND REENGAGED THE AUTOPLT. ATC ASKED US TO CONFIRM OUR ALT AND WE SAID WE WERE LEVELING AT 13000 FT. THE AUTOPLT PERFORMED NORMALLY THE REST OF THE FLT. I GUESS EVEN THOUGH WE HAVE ALL THIS FANCY NEW EQUIP (CRT'S; MOVING MAP; AUTOPLT); WE STILL NEED TO PAY CLOSE ATTN TO SIMPLE THINGS LIKE LEVELING OFF.