NMAC.

Narrative

ON JAN/BB/95; I WAS IN COMMAND OF FLT XX FROM SAN JUAN TO ANTIGUA. I WAS OPERATING ON AN IFR CLRNC IN LEVEL FLT AT 4000 FT. AT A DISTANCE OF 19 DME ON G-633 FROM ANU VOR INBOUND TO ANTIGUA. AT THE TIME THIS INCIDENT OCCURRED; I WAS IN VFR CONDITIONS WITH A CUMULUS CLOUD FORMATION 1/2 MI AHEAD. I WITNESSED AN ACFT EMERGE FROM THE CLOUDS AHEAD AT MY ALT ON A COLLISION COURSE. DUE TO THE PROX OF OUR ACFT; I HAD NO TIME TO INITIATE AN EVASIVE MANEUVER. FORTUNATELY WE MISSED EACH OTHER BY AN ESTIMATED HORIZ DISTANCE OF 200 FT. I HAD NO TIME TO INITIATE AN EVASIVE MANEUVER. FORTUNATELY WE MISSED EACH OTHER BY AN ESTIMATED HORIZ DISTANCE OF 200 FT. I HAD NO DIFFICULTY IDENTING THE ACFT AS A TWIN OTTER. JUST PRIOR TO THIS INCIDENT; ATC NOTIFIED ME OF VFR TFC IN MY VICINITY AT 4500 FT. AFTER LNDG I SPOKE WITH MR X OF BIRD INTL ARPT TWR. HE INFORMED THE CC TWIN OTTER WAS OPERATING VFR AND SHOULD HAVE BEEN AT THE APPROPRIATE VFR ALT OF 4500 FT. OBVIOUSLY; BY EMERGING FROM A CLOUD; THE TWIN OTTER WAS NOT ADHERING TO VFR; REGARDLESS OF HIS ALT. THIS VIOLATION OF FARS CREATED A THREAT TO NOT ONLY MY LIFE BUT TO THOSE PAX ON BOARD THE CC FLT AS WELL.