GA small aircraft landing on a frozen lake covered with 12 inches of snow and was unable to takeoff....

Attributes
ACN	84532
Time
Date	198803
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : sea airport : lkisabelle
State Reference	WA
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : fsd
Operator	general aviation : instructional
Make Model Name	Small Aircraft
Flight Phase	landing other
Flight Plan	None
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : instrument pilot : commercial pilot : cfi
Experience	flight time last 90 days : 150 flight time total : 1400 flight time type : 900
ASRS Report	84532
Events
Anomaly	inflight encounter other other anomaly other spatial deviation
Independent Detector	other flight crewa
Resolutory Action	flight crew : declared emergency none taken : unable none taken : detected after the fact
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Aircraft was an small aircraft floatplane and the incident involved making a low approach to and inadvertent landing in a high mountain lake, lake isabelle, elevation 2800' MSL, OAT was 40 degrees F. The approach was normal and I have landed many times in this lake in the summer. The lake is adequate in size and has a non-mountainous opening for a safe go around if needed. However, my judgement was inadequate in that I thought that the seemingly ice appearance of the lake surface was actually ice with about 12' of snow cover. I was making a glassy water type of approach (very gentle letdown) and was not concerned with contact of what I thought was ice as there was plenty of room, 4000+' of lake ahead of me. However, as soon as my floats did touch the surface (this was not planned and does happen with glassy water apches and snow/whiteouts), the wet snow created quite a lot of drag and a full landing was the result. There was no damage to the aircraft or personnel, however takeoff was not possible and I had to call and arrange for a helicopter to be taken out. My thoughts on the matter looking back were that I was dealing with a situation beyond my experience level and that it was a learning experience.

Original NASA ASRS Text

Title: GA SMA LNDG ON A FROZEN LAKE COVERED WITH 12 INCHES OF SNOW AND WAS UNABLE TO TKOF. ACFT STRANDED AND HELICOPTER CALLED TO TRANSPORT PLT.

Narrative: ACFT WAS AN SMA FLOATPLANE AND THE INCIDENT INVOLVED MAKING A LOW APCH TO AND INADVERTENT LNDG IN A HIGH MOUNTAIN LAKE, LAKE ISABELLE, ELEVATION 2800' MSL, OAT WAS 40 DEGS F. THE APCH WAS NORMAL AND I HAVE LANDED MANY TIMES IN THIS LAKE IN THE SUMMER. THE LAKE IS ADEQUATE IN SIZE AND HAS A NON-MOUNTAINOUS OPENING FOR A SAFE GO AROUND IF NEEDED. HOWEVER, MY JUDGEMENT WAS INADEQUATE IN THAT I THOUGHT THAT THE SEEMINGLY ICE APPEARANCE OF THE LAKE SURFACE WAS ACTUALLY ICE WITH ABOUT 12' OF SNOW COVER. I WAS MAKING A GLASSY WATER TYPE OF APCH (VERY GENTLE LETDOWN) AND WAS NOT CONCERNED WITH CONTACT OF WHAT I THOUGHT WAS ICE AS THERE WAS PLENTY OF ROOM, 4000+' OF LAKE AHEAD OF ME. HOWEVER, AS SOON AS MY FLOATS DID TOUCH THE SURFACE (THIS WAS NOT PLANNED AND DOES HAPPEN WITH GLASSY WATER APCHES AND SNOW/WHITEOUTS), THE WET SNOW CREATED QUITE A LOT OF DRAG AND A FULL LNDG WAS THE RESULT. THERE WAS NO DAMAGE TO THE ACFT OR PERSONNEL, HOWEVER TKOF WAS NOT POSSIBLE AND I HAD TO CALL AND ARRANGE FOR A HELI TO BE TAKEN OUT. MY THOUGHTS ON THE MATTER LOOKING BACK WERE THAT I WAS DEALING WITH A SITUATION BEYOND MY EXPERIENCE LEVEL AND THAT IT WAS A LEARNING EXPERIENCE.

Data retrieved from NASA's ASRS site as of August 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.

GA small aircraft landing on a frozen lake covered with 12 inches of snow and was unable to takeoff. Aircraft stranded and helicopter called to transport pilot.