RWY LIGHTS FAILED DURING A PERIOD OF LOW VISIBILITY AT SEA.

Narrative

ON SEP/XX/94; THE RWY LIGHTS FAILED ON 3 SEPARATE OCCASIONS. AT XA23 ACR X; ON A 1 1/2 MI FINAL TO RWY 16R; WAS SENT AROUND IN LOW IFR CONDITIONS WHEN THE LIGHTS FAILED. AT APPROX XA34; THE PORT OF SEATTLE (POS) RPTED THE LEAD IN LIGHT FOR THE STOP BARS HAD FAILED. AT XB26; ACR Y ENTERED RWY 16L AND RPTED THE RWY LIGHTS HAD FAILED. AT XB45; THE POS CHANGED GENERATORS AND THE LIGHTS WERE OUT FOR SEVERAL MINS. THE POS DID A RWY CHK AT XB48 AND RPTED THAT THE RWY LIGHTS WERE WORKING PROPERLY. AT XB52; WITH Z ON HIS DEP ROLL; THE RWY 16L LIGHTS FAILED AGAIN. THE RWY VISUAL RANGE WAS ONLY 600 FT AT THE TIME OF HIS DEP. THE POS LIGHTS HAVE HAD A HISTORY OF POOR RELIABILITY. COMMERCIAL PWR AND BACKUP SUBSTATIONS ALONG WITH STANDBY GENERATORS HAVE FAILED TO PROVIDE CONTINUOUS PWR FOR THE RWY LIGHTING SYS. THE REASONS FOR THE FAILURES HAVE NOT ALWAYS BEEN CLR. WE ARE LOSING CONFIDENCE IN THESE SYS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THE PORT OF SEATTLE HAS NOW INSTALLED A CONTINUOUS PWR SOURCE TO THE RWY LIGHTS AND INSTALLED AIR COOLING TO THE VAULTS FOR THE LIGHTS. THIS SEEMS TO HAVE SOLVED THE PROB.