2 ISSUES INVOLVED AS A G4 LANDS ON THE WRONG RWY AFTER THE OUTER PANE OF THE FO'S WINDOW HEAT CTL FAILS; EXPLODING HIS OUTER PANE; ON SHORT FINAL TO RWY 10 AT TJSJ; PR.

Narrative

THIS IS MY BEST RECOLLECTION OF EVENTS DURING THE APCH AND LNDG OF A GULFSTREAM 4 INTO SAN JUAN; PR; ON JAN/THU/01. AS SIC; I WAS IN THE R SEAT AND WAS PNF. AS I REMEMBER; SAN JUAN APCH HAD GIVEN US A DSCNT TO 3000 FT ON A 180 DEG HDG. AT APPROX 15 NM FROM THE ARPT WE WERE GIVEN A HEADING CHANGE TO 160 DEGS AND DSND TO 2000 FT. ON THIS HEADING; APCH INSTRUCTED US TO INTERCEPT THE LOC TO THE RWY. I BELIEVE I QUESTIONED IF IT WAS RWY 8 AND WAS TOLD NEGATIVE IT WAS RWY 10. I VERIFIED THAT THE LOC FREQ FOR RWY 10 WAS IN THE NAV RADIOS AND CONTINUED ON THE 180 DEG HDG. ON INTERCEPTING THE LOC; APCH ASKED US TO RPT THE ARPT IN SIGHT. I STARTED TO PERFORM THE BEFORE LNDG CHKLIST. IN THE PROCESS; I SCANNED OUTSIDE THE ACFT TO SEE IF I COULD ACQUIRE THE ARPT VISUALLY. I DID SEE THE ARPT AND ASKED THE PLT IF HE ALSO HAD IT. HE VERIFIED THAT HE HAD THE ARPT IN SIGHT AND I RPTED THAT TO APCH. APCH THEN TOLD US TO CONTACT THE TWR. I MADE THE INITIAL CALL TO THE TWR AND I REMEMBER THE TWR ACKNOWLEDGING THE CALL AND GIVING US CLRNC TO LAND RWY 8. I DO REMEMBER THE TWR TELLING US TO REMAIN ON THE LOC UNTIL INTERCEPTING FINAL (OR WORDS TO THAT EFFECT). I SAW THE ARPT IN FRONT OF US. WHILE LOOKING OUTSIDE I HEARD WHAT SOUNDED LIKE A SHOTGUN BLAST AND MY WINDOW IMMEDIATELY SHATTERED. I INSTINCTIVELY LOWERED MY HEAD BELOW THE GLARE SHIELD NOT REALLY COGNIZANT OF WHAT HAD HAPPENED OR WHAT WAS ABOUT TO HAPPEN. AS I LOOKED UP FROM MY LOWER PERSPECTIVE AT THE WINDOW. I FELT THE WINDOW WITH MY HAND TO DETERMINE IF IT WAS AN INNER OR OUTER PANE THAT SHATTERED. AS MY HAND DIDN'T FEEL ANY ROUGH EDGES I ASSUMED IT WAS THE OUTER PANE. I WAS SHAKEN AND WAS TRYING TO FIGURE OUT WHAT TO DO NEXT. MY IMMEDIATE REACTION WAS FOR US TO JUST GET THE ACFT ON THE GND SAFELY AND TAKE ANY OTHER STEPS WHEN WE WERE SAFELY ON THE GND. THE PLT ASKED ME TO COMPLETE THE REMAINING STEPS IN THE BEFORE LNDG CHKLIST WHICH I CONTINUED TO DO. AS I LOOKED AT THE WINDOW I SAW SMALL FLAMES AND ARCING AT THE VERY TOP WHERE THE HEATING ELEMENT WAS CONNECTED TO THE ELECTRICAL CONNECTION. I IMMEDIATELY TURNED OFF THE WINDOW HEAT. THE ARCING AND FLAME DISAPPEARED SHORTLY. I VERIFIED THE GEAR AND FLAPS WERE IN THE CORRECT POS; WE WERE ON THE GS AND LNDG WAS IMMINENT. AFTER TOUCHDOWN WE ROLLED ALMOST ALL THE WAY TO THE END. IT WAS AT THIS POINT THAT I REALIZED THAT WE HAD LANDED ON RWY 10 INSTEAD OF RWY 8. AS WE CLRED THE RWY WE WERE GIVEN TAXI INSTRUCTIONS TO OUR DEST ON THE FIELD AND REQUESTED TO CALL THE TWR SUPVR WHEN WE GOT TO A TELEPHONE. IN DISCUSSING THE SIT WITH THE PLT; WE BELIEVE THAT THE EVENT OF THE SUDDEN BLAST NOISE AND RESULTANT SHATTERING OF THE WINDOW UNNERVED BOTH OF US. THIS CAUSED US TO LOSE CONCENTRATION AND FOCUS. WE BOTH FEEL THAT AN AGREEMENT BTWN US AS TO WHO WOULD DO WHAT TASKS PROBABLY WOULD HAVE ALLOWED EACH OF US TO CONCENTRATE ON ONLY THOSE IMPORTANT TASKS. THE PLT SHOULD HAVE CONCENTRATED ON FLYING THE ACFT AND COMMUNICATING WITH ATC WHILE I SHOULD HAVE BEEN FOCUSED ON THE COMPLETION OF THE LNDG CHKLIST AND TAKING CARE OF THE WINDOW SIT. WE BOTH OUTLINE DUTIES AS TO WHO WILL DO WHAT IN THE EVENT OF AN EMER OR UNUSUAL EVENT IN THE TKOF PHASE OF FLT BUT REALLY NEVER CONSIDERED ADDRESSING THE OCCURRENCE OF AN EVENT IN THE LNDG PHASE. IT HAS NOT BEEN DETERMINED AS TO WHAT CAUSED THE WINDOW TO SHATTER BUT THE EVIDENCE POINTS TO A MALFUNCTION OF THE WINDOW HEAT TEMP CTLR. IT IS POSSIBLE THAT AN ELECTRICAL PWR SURGE FROM THE CONVERTER TO THE TEMP CTLR COULD HAVE CAUSED THE HEATING ELEMENT TO EXCEED NORMAL LIMITS AND THUS CAUSED THE OUTER WINDOW PANEL TO RUPTURE AND SHATTER. THE TEMP INCREASE WAS PROBABLY A GRADUAL OCCURRENCE STARTING SOME TIME BEFORE THE EVENT AND FINALLY CAUSING THE SHATTERING. THERE WAS NO EVIDENCE OF A BIRD OR FOREIGN OBJECT STRIKE.