The Lake Renegade that crashed during takeoff from the AirVenture 2017 seaplane base in rough water had its flaps up, contrary to manufacturer’s recommendations, according to the NTSB’s preliminary report. The 84-year old pilot and one of his passengers was killed in the accident. A second passenger survived with minor injuries. According to the NTSB, persons at the seaplane base expressed concern to the pilot regarding the rough water departure.
Source: avwebFlaps Up In Fatal Rough Water Takeoff