C150 attempting takeoff from 800 ft strip with reporter calculating he would need 748 ft, would not ...

Narrative:

On jul/tue/97 at about XA30, I experienced a non rptable ditching incident involving an aircraft. I was attempting to take off from a popular alaska fishing destination, the lake creek strip in my C150C. The aircraft was in good mechanical condition, and was modified with oversize tires and heavy duty landing gear. The WX in that part of alaska had been warm that week, increasing glacial melt and raising the level of the river, which defines both ends of the landing strip. After landing, and having found the landing 'tighter' than expected, I paced off the strip and found it to be about 800 ft long. Consulting with the aircraft operating manual, I determined that the required takeoff distance for the conditions at maximum gross weight was 748 ft. As the aircraft was well under maximum gross weight, and since the strip ended at the water's edge, with no tall obstructions ahead, I determined that a takeoff was possible and planned to accelerate in ground effect over the water if needed. Upon takeoff, however, the aircraft was unable to establish a climb, and in fact began to settle over the water. The tires touched down into the water, costing needed airspeed several times. With the conditions of deteriorating airspeed, and lack of climb, it became apparent that the aircraft would not attain a flyable condition, and I elected to do a controled descent into the water. Many who have attempted to force the aircraft to fly at too low an airspeed have suffered low altitude, 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 aircraft as it sank. The aircraft 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 aircraft occurred, and no oil or fuel leakage or oil slick was noted in the water.

Original NASA ASRS Text

Title: 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.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	373566
Time
Date	199707
Day	Tue
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : skw
State Reference	AK
Altitude	agl bound lower : 0 agl bound upper : 50
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : personal
Make Model Name	Cessna 150
Operating Under FAR Part	Part 91
Flight Phase	climbout : initial landing other other
Flight Plan	VFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : private
Experience	flight time last 90 days : 35 flight time total : 158 flight time type : 53
ASRS Report	373566
Events
Anomaly	other anomaly other anomaly other other spatial deviation
Independent Detector	other flight crewa
Resolutory Action	flight crew : declared emergency none taken : unable
Consequence	other
Supplementary
Primary Problem	Flight Crew Human Performance

C150 attempting takeoff from 800 ft strip with reporter calculating he would need 748 ft, would not climb and settled into the river. Aircraft was carried downstream and washed up on a sandbar. Though damaged, not within NTSB criteria.