Accident Details
On May 9, 2023, about 1215 Pacific daylight time, a float-equipped Aviat A-1C-180 Husky, registration N416AG, was destroyed when it crashed near Steilacoom Lake in Lakewood, Washington. The pilot and pilot-rated passenger sustained serious injuries. The flight was operated as a personal flight under Title 14 Code of Federal Regulations Part 91.
According to the pilot and passenger, who also served as the pilot's airframe and powerplant mechanic, they departed from Olympia Regional Airport (OLM) with plans to overfly the pilot's house and land on Lake Steilacoom, where the pilot resided. The pilot reported that the accident occurred on what would have been his second water landing that day. On approach, the gear selector lever was in the up position, with four blue lights illuminated on the gear position indicator panel. The pilot aimed to touch down near the midpoint of a waterski slalom course marked by buoys, approximately 1,800 feet from the south shoreline. When the airplane was about 2 to 3 feet above the water, the landing gear advisory system (LGAS) issued an aural "CHECK GEAR" advisory. The pilot stated he was unable to visually confirm that the left nose wheel was fully retracted and elected to perform a go-around.
The passenger reported that during preparation for landing, the pilot gave him the checklist to read aloud; both confirmed the landing gear was up for a water landing, and they checked a second time during the approach. About 2 to 3 feet above the water, they heard the aural gear advisory. Both pilots looked outside to verify the gear was up. The passenger further stated that the pilot added power to execute a go-around, and at some point the stall warning horn sounded. The passenger believed the indicated airspeed during the go-around was about 60 knots and instructed the pilot to "keep the nose down." As they approached trees, the pilot expressed concern about hitting them, and shortly thereafter the airplane impacted and rapidly descended to the ground.
Flight and Environmental Factors
Automatic dependent surveillance-broadcast (ADS-B) data indicated that the airplane departed OLM about 1100, with the last data point recorded at 1209 on a southern track at an elevation of 450 feet on final approach to Steilacoom Lake. The distance between the last data point and the wreckage was approximately 5,200 feet.
The lake is about 1.5 miles long from north to south but is dissected in the middle by a peninsula and a roadway bridge. The landing area chosen by the pilot would have provided an available water distance of about 3,370 feet, with rising terrain and tall trees directly at the end. An approach slightly south over the bridge offered a water distance of about 4,630 feet.
The pilot had obtained his airplane single-engine sea rating in February 2023 and had purchased the airplane a little more than a month before the accident. He had accumulated 37 hours of flight experience in that make and model.
The pilot's flight instructor stated that he had flown with him in the accident airplane for about 30 hours, providing instruction for the seaplane rating and ferry flights. The instructor noted that the nose gear was difficult to see from the cockpit and that the LGAS could be distracting. He also described the lake as small, making a go-around "tight."
Winds reported by McChord Field Airport (TCM), located about 2.5 miles from the lake, at 1155 were from the north at 5 knots, and at 1255 were 6 knots. The landing was conducted to the south. The pilot had radioed TCM for wind conditions and reported calm winds; he overflew the lake and observed the water surface and flags, concluding the wind was calm.
Aircraft Systems and Examination
According to representatives of the float system manufacturer Wipaire, there are three methods to determine gear position: visual inspection of the nose gear, visual inspection of two indicator rods on the step of each float for the main gear, and the LGAS system. The LGAS incorporates a laser array mounted in the wing to detect whether the aircraft is over land or water. It activates when the airplane descends below 400 feet AGL and below the airspeed threshold set by the manufacturer. The LGAS compares the surface below the airplane with the gear position switches; if they disagree below 50 feet AGL, it issues an aural "Check Gear" announcement and a flashing red annunciator light. The pilot can cancel both advisories by pressing the light.
The Airplane Flight Manual (AFM) supplement emphasizes that the LGAS is advisory and should not replace visual checks. Under certain conditions, such as approaches where the surface changes from land to water below 30 feet AGL and below the airspeed threshold, the LGAS may issue an advisory even if the gear is correctly positioned. The system can also exhibit errors due to relative speed effects, shallow or muddy water, heavy wind streaks, foam, or floating debris that distort reflectivity. The AFM instructs that if the annunciation occurs below 50 feet AGL, the pilot should abort the landing and initiate an immediate go-around, then determine the cause at a safe altitude.
A postaccident examination confirmed flight control continuity from all surfaces to their respective cockpit controls. The flap position could not be determined, and flight instruments were destroyed by fire. The fuselage, wings, and left float sustained extensive thermal damage. Examination of the floats and landing gear revealed that all four landing gear were in the retracted (up) position. The left and right nose gear assemblies were intact and allowed free caster. The right main gear visual indicator rod and actuator indicated the right main was retracted. The left main gear visual indicator rod was thermally damaged, but the left gear actuator indicated the left main wheel was retracted.
According to the AFM supplement, at maximum gross weight with full flaps, the landing distance is approximately 1,350 feet. The takeoff and balked landing rate of climb performance chart, for maximum gross weight with a 76-inch propeller and flaps up, indicates a rate of climb of about 778 feet per minute.