C172 float plane makes uneventful water landing after engine failure due to water contaminated fuel.

Attributes
ACN	597935
Time
Date	200310
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : sea.airport
State Reference	WA
Altitude	agl bound lower : 0 agl bound upper : 200
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : instructional
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Navigation In Use	other
Flight Phase	descent : approach landing : roll
Flight Plan	None
Person 1
Affiliation	other
Function	instruction : instructor
Qualification	pilot : instrument pilot : cfi
Experience	flight time last 90 days : 103 flight time total : 3113 flight time type : 2381
ASRS Report	597935
Person 2
Affiliation	other
Function	instruction : trainee
Events
Anomaly	aircraft equipment problem : critical non adherence : published procedure other anomaly other anomaly other
Independent Detector	other flight crewa other flight crewb
Resolutory Action	flight crew : landed in emergency condition
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance Weather
Primary Problem	Flight Crew Human Performance

Narrative:

The engine on a cessna C172-xp float plane failed on short final for landing on lake. The aircraft was at approximately 200 ft AGL, over the lake, when the engine stopped. Student pilot and instructor aboard. The student made a successful engine-out landing. There was no damage to the plane, nor injuries to occupants. The problem was caused by water in 1 fuel tank which was not detected during the preflight inspection. During the preflight, the instructor found the right fuel cap loose and only partially seated. A heavy rainstorm had dropped 5+ inches of rain on the airplane after its previous flight and so the instructor and student were concerned about water in the fuel. However 4 full samples from the tank revealed no water. Concluding that the tank had no water the instructor elected to fly. Approximately 1 hour into the flight, the engine stoppage occurred. After landing, the pilots sampled both tanks. The right tank had water. It was necessary to switch to the left tank and drain the gasolator for 2-3 mins before the engine could be restarted. The engine stoppage was caused by an inadequate preflight inspection. After finding the open right tank, the pilots should have requested that the tank be drained. The instructor incorrectly relied on a belief that any water would be revealed by sumping the tank 3 extra times. The float plane sits nose low when stored on the ground. The sumps are at the bottom rear of the tanks and so, evidently, water can be trapped forward in the tank and not be discovered by sumping without raising the nose.

Original NASA ASRS Text

Title: C172 FLOAT PLANE MAKES UNEVENTFUL WATER LNDG AFTER ENG FAILURE DUE TO WATER CONTAMINATED FUEL.

Narrative: THE ENG ON A CESSNA C172-XP FLOAT PLANE FAILED ON SHORT FINAL FOR LNDG ON LAKE. THE ACFT WAS AT APPROX 200 FT AGL, OVER THE LAKE, WHEN THE ENG STOPPED. STUDENT PLT AND INSTRUCTOR ABOARD. THE STUDENT MADE A SUCCESSFUL ENG-OUT LNDG. THERE WAS NO DAMAGE TO THE PLANE, NOR INJURIES TO OCCUPANTS. THE PROB WAS CAUSED BY WATER IN 1 FUEL TANK WHICH WAS NOT DETECTED DURING THE PREFLT INSPECTION. DURING THE PREFLT, THE INSTRUCTOR FOUND THE R FUEL CAP LOOSE AND ONLY PARTIALLY SEATED. A HVY RAINSTORM HAD DROPPED 5+ INCHES OF RAIN ON THE AIRPLANE AFTER ITS PREVIOUS FLT AND SO THE INSTRUCTOR AND STUDENT WERE CONCERNED ABOUT WATER IN THE FUEL. HOWEVER 4 FULL SAMPLES FROM THE TANK REVEALED NO WATER. CONCLUDING THAT THE TANK HAD NO WATER THE INSTRUCTOR ELECTED TO FLY. APPROX 1 HR INTO THE FLT, THE ENG STOPPAGE OCCURRED. AFTER LNDG, THE PLTS SAMPLED BOTH TANKS. THE R TANK HAD WATER. IT WAS NECESSARY TO SWITCH TO THE L TANK AND DRAIN THE GASOLATOR FOR 2-3 MINS BEFORE THE ENG COULD BE RESTARTED. THE ENG STOPPAGE WAS CAUSED BY AN INADEQUATE PREFLT INSPECTION. AFTER FINDING THE OPEN R TANK, THE PLTS SHOULD HAVE REQUESTED THAT THE TANK BE DRAINED. THE INSTRUCTOR INCORRECTLY RELIED ON A BELIEF THAT ANY WATER WOULD BE REVEALED BY SUMPING THE TANK 3 EXTRA TIMES. THE FLOAT PLANE SITS NOSE LOW WHEN STORED ON THE GND. THE SUMPS ARE AT THE BOTTOM REAR OF THE TANKS AND SO, EVIDENTLY, WATER CAN BE TRAPPED FORWARD IN THE TANK AND NOT BE DISCOVERED BY SUMPING WITHOUT RAISING THE NOSE.

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.