MLG MISSES XING RESTR ON DSCNT.

Narrative

ENRTE FROM ROC - PHL AND CRUISING AT FL250. TKOF; CLB AND INITIAL CRUISE HAD BEEN NORMAL. ABOUT 55 MI N OF HAR; DSCNT CLRNC WAS RECEIVED TO CROSS 15 MI N OF HAR AT FL180. DSCNT WAS NOT INITIATED IMMEDIATELY BECAUSE OF FUEL BURN CONSIDERATIONS AS WELL AS BUMPY RIDES AT LOWER ALTS. IN THE ENSUING 35 MI; DISTRS ABOUNDED: FLT ATTENDANT CAME INTO THE COCKPIT FOR DRINK ORDERS; SIGHT- SEEING DUE TO NEARBY UNLIMITED VISIBILITY AND PRE- OCCUPATION WITH A MINOR MECHANICAL PROB AMONG THEM. AT ABOUT 20 MI N; CTR QUESTIONED OUR LACK OF DSCNT. WE IMMEDIATELY INITIATED A PWR OFF; SPD BRAKE. EXTENDED DSCNT AND REQUESTED AN OFF-COURSE VECTOR. WE LEVELED OFF AT FL180 ABOUT 10 MI N OF HAR; MISSING BY 5 MI. REMAINDER OF FLT WAS NORMAL. THERE ARE A LOT OF FACTORS INVOLVED IN THIS ALT BUST. FOR STARTERS; I'M NEW ON THIS AIRPLANE; BUT I'M JUST EXPERIENCED ENOUGH ON IT TO START FEELING 'COMFORTABLE.' THAT 'COMFORTABLE' FEELING MAY HAVE LED ME TO BE SOMEWHAT LAX IN MY SITUATIONAL AWARENESS. ON MY PREVIOUS AIRPLANE; I UTILIZED THE 'DECISION HT' LIGHT ON THE RADIO ALTIMETER TO REMIND ME OF DSCNT CLRNC. I'VE CARRIED THIS HABIT OVER ON TO MY NEW AIRPLANE BUT THE 'DECISION HT' IS NOT NEARLY AS BRIGHT OR PROMINENT; SO I OVERLOOKED IT. ALSO; MY NEW PLANE HAS #1 AND #2 DME DISPLAYED SIDE BY SIDE WHICH OCCASIONALLY CONFUSES ME AT FIRST GLANCE; UNTIL I SORT THINGS OUT. I MUST ALSO ADMIT TO SOME 'SIGHT-SEEING;' BECAUSE THE VISIBILITY WAS UNLIMITED. IT WAS A SATURDAY; SO TFC AND RADIO CHATTER WAS LIGHT; AND WE WERE FLYING OVER MY 'OLD STOMPING GND.' NO EXCUSE; JUST EXPLANATION. WE SELDOM GET SUCH GOOD VISIBILITY BACK E. A MINOR SWITCH PROB WAS ALSO OCCUPYING SOME OF OUR ATTN; MORE SO THEN WAS NECESSARY. RATHER THAN JUST WRITE IT UP IN PHL; WE WERE 'TROUBLE-SHOOTING' THE PROB. POOR TIMING. FINALLY; I WAS FLYING WITH A GOOD FRIEND OF MINE; SO I MAY HAVE LET MY GUARD DOWN; JUST A LITTLE; BECAUSE HE'S A SHARP PLT AND I FIGURED HE'D KEEP AN EYE ON ME. FROM NOW ON; I'LL KEEP AN EYE ON THE DISTRS AND KEEP MY GUARD UP; AND HE WON'T HAVE TO KEEP AN EYE ON ME.