Small aircraft aircraft on floats hit a rock on takeoff.

Attributes
ACN	412219
Time
Date	199808
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : ktn
State Reference	AK
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air taxi
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 135
Flight Phase	climbout : takeoff
Flight Plan	VFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : cfi pilot : atp
Experience	flight time last 90 days : 225 flight time total : 12000 flight time type : 500
ASRS Report	412219
Person 2
Affiliation	Other
Function	observation : passenger
Qualification	other other : other
Events
Anomaly	conflict : ground critical
Independent Detector	other flight crewa
Resolutory Action	none taken : insufficient time other
Consequence	other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	other

Narrative:

Landed on alpine lake as part of a regular feature of a sightseeing flight in wilderness area. During subsequent takeoff, struck a rock and damaged both floats which began taking on water. Taxied to shore, discharged passenger ( no injuries) and secured aircraft. Aircraft remained afloat. This lake is a large, deep lake that sees regular activity from similar air taxi operations. I had operated from this lake before and watched similar activity without ever observing the rock or being warned of its presence. I was thereby lulled into the belief that it was a lake without obstacles and did not overfly to check the area I would be operating in, as I would do with any area that was new to me. There was still the opportunity to see the rock during the approach and landing or before I began the takeoff. I believe that was missed because the rock only extended 3- 4 inches above the surface and the surface was rippled with 3-5 KTS of wind, making the rock indistinguishable. If the surface was calm or the waves breaking over it, it may have been more apparent. An overflt should have detected the rock, however, these flts are time limited and one of the reasons for operating from a familiar area is to preclude this step. Obviously, the time saved is not worth it.

Original NASA ASRS Text

Title: SMA ACFT ON FLOATS HIT A ROCK ON TKOF.

Narrative: LANDED ON ALPINE LAKE AS PART OF A REGULAR FEATURE OF A SIGHTSEEING FLT IN WILDERNESS AREA. DURING SUBSEQUENT TKOF, STRUCK A ROCK AND DAMAGED BOTH FLOATS WHICH BEGAN TAKING ON WATER. TAXIED TO SHORE, DISCHARGED PAX ( NO INJURIES) AND SECURED ACFT. ACFT REMAINED AFLOAT. THIS LAKE IS A LARGE, DEEP LAKE THAT SEES REGULAR ACTIVITY FROM SIMILAR AIR TAXI OPS. I HAD OPERATED FROM THIS LAKE BEFORE AND WATCHED SIMILAR ACTIVITY WITHOUT EVER OBSERVING THE ROCK OR BEING WARNED OF ITS PRESENCE. I WAS THEREBY LULLED INTO THE BELIEF THAT IT WAS A LAKE WITHOUT OBSTACLES AND DID NOT OVERFLY TO CHK THE AREA I WOULD BE OPERATING IN, AS I WOULD DO WITH ANY AREA THAT WAS NEW TO ME. THERE WAS STILL THE OPPORTUNITY TO SEE THE ROCK DURING THE APCH AND LNDG OR BEFORE I BEGAN THE TKOF. I BELIEVE THAT WAS MISSED BECAUSE THE ROCK ONLY EXTENDED 3- 4 INCHES ABOVE THE SURFACE AND THE SURFACE WAS RIPPLED WITH 3-5 KTS OF WIND, MAKING THE ROCK INDISTINGUISHABLE. IF THE SURFACE WAS CALM OR THE WAVES BREAKING OVER IT, IT MAY HAVE BEEN MORE APPARENT. AN OVERFLT SHOULD HAVE DETECTED THE ROCK, HOWEVER, THESE FLTS ARE TIME LIMITED AND ONE OF THE REASONS FOR OPERATING FROM A FAMILIAR AREA IS TO PRECLUDE THIS STEP. OBVIOUSLY, THE TIME SAVED IS NOT WORTH IT.

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.