Accident Details
On June 27, 2008, at approximately 1730 Pacific daylight time, a Cessna A185F (registration N5403E) nosed over on landing touchdown in the Columbia River near Kelso-Longview Airport in Rainier, Oregon. The amphibious airplane was operated by Armstrong Marine, Inc., under 14 Code of Federal Regulations Part 91. The flight originated from Blue Ribbon Airport in Sequim, Washington, around 1620. Visual meteorological conditions prevailed; no flight plan was filed. The pilot, who held a private pilot certificate, received a minor injury. The airplane sustained substantial damage to the wings.
Pilot Actions
According to a written statement, the pilot was not familiar with the river intended for landing. After overflying the landing spot, he executed a normal approach and performed a pre-landing check of fuel, propeller, mixture, and landing gear selector. He landed at 60 knots, and the airplane immediately became inverted. The pilot exited the airplane through a window.
Post-Accident Examination
Post-accident investigation determined that the landing gear was extended, but the gear selector was in the retracted position. The pilot believed a hydraulic leak in the left float prevented the landing gear from retracting. A National Transportation Safety Board investigator examined the airplane on July 17, 2008, at the pilot's hangar in Sequim. No anomalies were noted with the right float. The investigator observed hydraulic fluid within the number seven and eight bulkheads of the left float. Both hydraulic lines for extending from the left float to the fuselage were removed at the fuselage attach point. Compressed air applied to one line caused hydraulic fluid to leak from the tension actuator. The tension actuator was secure to both forward and aft mounts. During removal, the gasket surrounding the actuator was cut, and the internal structure of the bulkhead exhibited a slight tear or crack originating from the gasket mount. The hydraulic accumulator on the engine firewall was undamaged; its fluid quantity sight gauge showed no sustainable level of fluid.
Actuator Testing
On September 22, 2008, at Kenmore Air in Kenmore, Washington, the Safety Board investigator supervised examination of the left float tension actuator. Both forward and aft pins were intact and safety wired. The actuator was installed on a test rig. When hydraulic pressure of 1,000 psi was applied to the forward hydraulic port, no leaks were observed. However, pressure applied to the aft hydraulic port caused extensive leaking around the rear seal. The securing pin safety wire was cut and removed; multiple attempts to remove the pin using a punch and hammer were unsuccessful. Corrosion was observed around and on the aft securing pin.