Accident Overview
On December 5, 2017, at approximately 1835 mountain standard time, a Piper PA-34-200T, registration N47536, sustained substantial damage following an accident near Glendale, Arizona. The flight instructor and the commercial pilot receiving instruction were uninjured. The flight was conducted under Title 14 Code of Federal Regulations Part 91 as a personal flight.
Sequence of Events
The instructor reported that the commercial pilot, who was flying the airplane, had successfully completed two simulated engine failure maneuvers in the traffic pattern. During the third traffic pattern, the instructor simulated a right engine failure. While on base leg, the pilot extended the landing gear and confirmed via the indicator lights that all three landing gear were down and locked. Upon touchdown, the left wing "dipped" and the airplane bounced back into the air. The instructor took control and applied full power to both engines in an attempt to climb, but the nose dropped and the airplane drifted left. Unable to climb, the instructor retarded both throttle and mixture controls, attempting to maintain directional control while applying brakes. The airplane departed the left side of the runway and came to a stop in the adjacent dirt area.
Post-Accident Examination
Examination of the accident site showed that the airplane landed with all three landing gear extended; each tire left a skid mark on the runway surface left of the centerline. Landing gear imprints were visible in the dirt where the airplane veered off. The left propeller and nose impacted a runway edge light and the 1,000-foot distance marker. The left main landing gear collapsed after striking the distance marker, as evidenced by wide tire marks indicating the airplane rolled on the sidewall of the left tire.
Structural Analysis
Fracture surface examination of the left main landing gear revealed slant fractures consistent with an overstress failure. A small area coinciding with the forging flash line exhibited a flat fracture surface. Further analysis using a scanning electron microscope showed striations on this flat area, consistent with a fatigue fracture.