Accident Details
On September 3, 2019, at approximately 1315 Alaska daylight time, a Lake LA-4-200 amphibious airplane, registration N6672L, sustained substantial damage following a runway excursion at Girdwood Airport (AQY) in Girdwood, Alaska. The private pilot, who was the sole occupant, was not injured. The aircraft was operated by a private individual under 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed, and no flight plan was filed. The flight originated from Merrill Field (MRI) in Anchorage, Alaska, at 1230, with Girdwood as its destination.
Sequence of Events
According to the pilot, after departing Merrill Field, the landing gear and flaps failed to retract. He checked the hydraulic pump circuit breaker, which was not open, and observed a zero reading on the hydraulic pressure gauge. He then used the emergency hydraulic hand pump to successfully retract both the landing gear and wing flaps. Upon arrival at Girdwood, the pilot again used the hand pump to extend the landing gear and flaps. After touchdown, the wheel brakes did not function properly, hindering the pilot's ability to slow and steer the aircraft. The airplane subsequently exited the runway, traveled down an embankment, and came to rest on its left wing and hull, resulting in substantial damage to the left wing and fuselage.
Aircraft Systems Description
The Lake LA-4 Owner's Manual indicates that the airplane is equipped with a castering nose wheel, which requires differential braking for directional control. The hydraulic system operates the landing gear, flaps, and longitudinal trim. It consists of an integral pump and electric motor, pressure limit switch, accumulator, and reservoir, connected by piping, check valves, and restrictors. The brake system is independent of the hydraulic system.
Post-Accident Examination
An examination of the brake and primary flight control systems revealed no preaccident mechanical malfunctions or anomalies that would have precluded normal operation.
Weather Conditions
The closest official weather observation station to the accident site was Portage Glacier (PATO) in Whittier, Alaska, approximately 20 miles southeast of the accident site. At 1253, a METAR reported wind variable at 6 knots, visibility 10 statute miles, overcast cloud ceiling at 5,000 feet, temperature 55°F, dew point 52°F, and an altimeter setting of 30.08 inches of mercury.