ERA23LA179

After obtaining fuel at a land-based airport, the pilot noted a small leak in the amphibious airplane’s hydraulic landing gear extension/retraction system. He subsequently departed for the accident flight. While the pilot was landing the airplane on a lake, he noticed that the landing gear were still extended; the airplane flipped over immediately upon touchdown and the airplane’s right wing was substantially damaged. Examination of the hydraulic system after the accident confirmed the small leak, but otherwise did not reveal evidence of a failure of the system. Additionally, the airplane was equipped with landing gear position indicating lights that should have alerted the pilot that the landing gear were not fully retracted before touchdown. Had the pilot observed this indication prior to landing, he would likely have aborted the landing attempt and prevented the accident.

On March 22, 2023, about 1648 eastern daylight time, a Piper PA-18AS, N1907A, was substantially damaged when it was involved in an accident on Crescent Lake in Umatilla, Florida. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to the pilot, he departed from his home base on Crescent Lake to refuel. Upon landing at Umatilla Airport (X23), he observed a small hydraulic fluid leak on the hand pump of the main landing gear while taxiing for fuel. After refueling, he proceeded to depart back to Crescent Lake. However, during the landing on the lake, he noticed that the nose landing gear was not fully retracted. When the nose gear contacted the water, the airplane flipped over and inverted. Following the accident, the pilot reported that the landing gear hand pump had failed to raise the landing gear as expected, and that an o-ring failure resulted in the pump leaking hydraulic fluid. An examination of the airplane by a Federal Aviation Administration (FAA) inspector revealed substantial damage to the right wing. Examination of the landing gear hydraulic system revealed a small amount of hydraulic fluid leaking from the landing gear hand pump, but that the leak was not significant enough to deplete the hydraulic system’s fluid. The inspector also identified wear marks on the hand pump shaft, but none that would have resulted in a failure of the pump. A review of the maintenance records indicated that an annual inspection had been conducted about five months before the accident, and no discrepancies were noted regarding the hydraulic system. According to the float manufacturer, the airplane’s gear selector was equipped with lights that indicated the landing gear position. Four blue lights illuminated when the gear was up, and four green lights illuminated when the gear was down. Additionally, a single red light indicated the operation of the hydraulic pump. Each gear position had its corresponding light. The hydraulic pump remained active until all landing gear components reached their intended positions. Although the floats did not have “locks," they did include an over-center main gear and a horizontally positioned nose gear system. Furthermore, the eight indicator lights operated independently of the gear hydraulic system and its functionality. A review of the airplane’s flight manual supplement, specifically on page 8, 9 and 13, stated: "Do not land on water unless the gear is fully retracted."