DURING THE AFTERNOON, THE PLT FLEW TO THE MILES RIVER IN MARYLAND WHERE HE MADE A WATER LANDING TO PICK UP A PASSENGER. WHEN HE LANDED, THE WATER SURFACE HAD RIPPLES WHICH HAD BEEN PRODUCED BY A LIGHT BREEZE. AT THAT TIME, THE PLT HAD NO TROUBLE SEEING THE SURFACE OF THE WATER. THE PLT THEN TOOK OFF WITH THE PASSENGER ON BOARD. LATER, WHEN THEY RETURNED TO LAND, THE WATER WAS GLASSY. THE PLT STATED THAT DURING THE LANDING, HE THOUGHT HIS APPROACH WAS PERFECT. HE STATED HE THOUGHT THAT HE WAS APRX 5 TO 6 FT ABOVE THE WATER & WAS JUST BEGINING TO FLARE WHEN THE ANPHIBIAN ACFT CRASHED. HE WAS THROWN FROM THE ACFT & REMEMBERED SWIMMING BACK. APRX 4 MIN AFTER THE ACCIDENT, BOTH OCCUPANTS WERE PULLED FROM THE WATER, BUT THE PASSENGER, WHO HAD WENT THRU THE WINDSHIELD, DIED LATER. NO SHOULDER HARNESS WAS INSTALLED. THE WATER VISIBILITY AT THE SITE WAS CLEAR. WHEN THE INVESTIGATOR LANDED ON GLASSY WATER THERE ON THE NEXT DAY, THERE WAS NO VISIBLE SURFACE, ALL HE COULD SEE WAS WHAT APPEARED TO BE THE RIVER BOTTOM.