ANC17FA010 · Piper PA 28-180

The non-instrument-rated private pilot and three passengers departed from an airport along a lakefront in an airplane not equipped or certified for flight into known icing conditions. A couple of minutes after the airplane departed, a pilot who was descending to land at the departure airport spoke with the accident pilot. The pilot of the descending airplane told the accident pilot that the tops of the clouds were about 2,000 ft. The accident pilot replied, "looking good under here, I'm gonna keep going." No further radio transmissions were received from the accident pilot. When the airplane failed to arrive at its intended destination, a search was launched. The day following the accident, airplane debris and personal items that were positively identified as belonging to the occupants of the airplane were found floating on the surface of the lake. The debris indicated that the airplane impacted the surface of the lake. Despite an extensive search, neither the occupants nor the airplane have been recovered, and, due to the depth of the lake, a recovery mission is unlikely.

Weather camera images, surface weather observations, and upper air observations indicated that the weather conditions at the time of the accident likely included freezing fog and mist, low visibilities and ceilings, and moderate or greater icing conditions in the clouds covering the accident area. Therefore, the accident flight likely encountered instrument meteorological conditions shortly after departure and rapidly began accumulating structural and/or induction icing. However, because the airplane was not available for examination by investigators, the possibility of mechanical failure or malfunction could not be ruled out.

Verbatim NTSB analysis and probable cause from the NTSB dataset