2 PAX CARRYING ATX SMA ACFT TOURING A GLACIER CANYON CAME IN CLOSE PROX TO EACH OTHER.

Narrative

2 ACFT CONDUCTING VFR TOURS OF ICE CAPS ON WILDERNESS AREA OF SE ALASKA FOR FARE-PAYING TOURIST PAX. ACFT WERE IN TRAIL +/-5 MI APART; 1000 FT ELEVATION SEPARATION; TALKING WITH EACH OTHER TO RPT POS/ALT AND TO KEEP VISUAL CONTACT. UPON FIRST ACFT PASSING OVER THE RIDGE LINE OF THE E TWIN; VISUAL CONTACT WAS LOST. AS SECOND ACFT APCHED RIDGE LINE VISUAL CONTACT STILL LOST BUT NOT CALL POS; #2 ASKED FOR INFO FIRST ACFT'S POS. FIRST AIRPLANE HAD TURNED L BEHIND A SECOND RIDGE TO VIEW THE FACE OF A HANGING GLACIER; AND DO A R 180 DEG TURN OUT OF THE GLACIER. THE SECOND ACFT CROSSED THE FIRST RIDGE LINE AND TURNED DOWN AND OUT OF THE GLACIER. WHILE CALLS WERE NORMALLY MADE TO CONFIRM POS; NEITHER ACFT KNEW THE EXACT LOCATION OF THE OTHER. FIRST ACFT CALLED AT 2200 FT AT THE BASE OF THE FIRST TWIN; THE SECOND RPTED IMMEDIATELY THE SAME POS; THE NEAR MISS HAD JUST HAPPENED BTWN THE CALLS. THE SECOND ACFT HAD JUST SLID UNDER THE FIRST ACFT WITHOUT EVER SEEING THE FIRST ACFT. THE FIRST ACFT PLT RPTED SEEING THE SECOND ACFT PASS UNDER BUT WITHOUT ANY OPPORTUNITY FOR EVASION. THE FIRST PLANE'S COPLT PAX OBSERVED THE INCIDENT AND THE SECOND ACFT'S PAX BEHIND PLT BRIEFLY OBSERVED THE INCIDENT. SECOND ACFT NEVER SAW FIRST ACFT TO AVOID (IN DOOR JAM; L; BLIND SPOT). COMS FAILED TO GIVE EACH PLT KNOWLEDGE OF WHEREABOUTS OF EACH OTHER. PLTS TALKED ABOUT THE SITUATION AS WELL AS CALLED A SAFETY MEETING TO BRIEF ALL OTHERS CONDUCTING TOURS AND AIR TAXI IN COMPANY OP.