C150 ATTEMPTING TKOF FROM 800 FT STRIP WITH RPTR CALCULATING HE WOULD NEED 748 FT; WOULD NOT CLB AND SETTLED INTO THE RIVER. ACFT WAS CARRIED DOWNSTREAM AND WASHED UP ON A SANDBAR. THOUGH DAMAGED; NOT WITHIN NTSB CRITERIA.

Narrative

ON JUL/TUE/97 AT ABOUT XA30; I EXPERIENCED A NON RPTABLE DITCHING INCIDENT INVOLVING AN ACFT. I WAS ATTEMPTING TO TAKE OFF FROM A POPULAR ALASKA FISHING DEST; THE LAKE CREEK STRIP IN MY C150C. THE ACFT WAS IN GOOD MECHANICAL CONDITION; AND WAS MODIFIED WITH OVERSIZE TIRES AND HVY DUTY LNDG GEAR. THE WX IN THAT PART OF ALASKA HAD BEEN WARM THAT WK; INCREASING GLACIAL MELT AND RAISING THE LEVEL OF THE RIVER; WHICH DEFINES BOTH ENDS OF THE LNDG STRIP. AFTER LNDG; AND HAVING FOUND THE LNDG 'TIGHTER' THAN EXPECTED; I PACED OFF THE STRIP AND FOUND IT TO BE ABOUT 800 FT LONG. CONSULTING WITH THE ACFT OPERATING MANUAL; I DETERMINED THAT THE REQUIRED TKOF DISTANCE FOR THE CONDITIONS AT MAX GROSS WT WAS 748 FT. AS THE ACFT WAS WELL UNDER MAX GROSS WT; AND SINCE THE STRIP ENDED AT THE WATER'S EDGE; WITH NO TALL OBSTRUCTIONS AHEAD; I DETERMINED THAT A TKOF WAS POSSIBLE AND PLANNED TO ACCELERATE IN GND EFFECT OVER THE WATER IF NEEDED. UPON TKOF; HOWEVER; THE ACFT WAS UNABLE TO ESTABLISH A CLB; AND IN FACT BEGAN TO SETTLE OVER THE WATER. THE TIRES TOUCHED DOWN INTO THE WATER; COSTING NEEDED AIRSPD SEVERAL TIMES. WITH THE CONDITIONS OF DETERIORATING AIRSPD; AND LACK OF CLB; IT BECAME APPARENT THAT THE ACFT WOULD NOT ATTAIN A FLYABLE CONDITION; AND I ELECTED TO DO A CTLED DSCNT INTO THE WATER. MANY WHO HAVE ATTEMPTED TO FORCE THE ACFT TO FLY AT TOO LOW AN AIRSPD HAVE SUFFERED LOW ALT; STALL SPIN ACCIDENTS; DRAMATICALLY INCREASING THE IMPACT FORCES. TO AVOID THIS; I CUT THE THROTTLE AND ENTERED THE WATER IN AN UPRIGHT ATTITUDE. THE WINDSHIELD BLEW INWARD FROM THE PRESSURE OF THE WATER; AND I EXITED THE ACFT AS IT SANK. THE ACFT WAS CARRIED DOWNSTREAM ABOUT 1 MI AND WASHED UP ON A SANDBAR; INTACT AND STILL UPRIGHT. DAMAGE; OTHER THAN WATER AND SILT INFILTRATION; WAS MINIMAL AND DID NOT MEET THE CRITERIA FOR NTSB RPTABILITY. NO INJURIES; OR DAMAGE TO PROPERTY OTHER THAN THE ACFT OCCURRED; AND NO OIL OR FUEL LEAKAGE OR OIL SLICK WAS NOTED IN THE WATER.