Small “Hop” Fractures Float Skin And Flips Maule
Here’s one for those constantly refining their landing technique and working on ways to use their aircraft more than once. On April 24, 2016, about 1500 eastern daylight time, an amphibious Maule M7 235-B, N367FS, was substantially damaged while attempting to land on a lake near Littleton, North Carolina. The private pilot and two passengers were not injured. Visual meteorological conditions prevailed and no flight plan was filed for the personal flight, which departed the lake around 1445. The airplane was owned and operated by the pilot/owner and the flight was conducted under the provisions of Title 14 Code of Federal Regulations Part 91.
According to the pilot, he owned the airplane for three weeks, and had performed about 30 water landings. He performed a pre-flight inspection, noted the tie-down ropes were tight, but did not find any other anomalies with the airplane. During the takeoff, the pilot noticed that the airplane was veering “severely” to the left; however, he continued the takeoff. The flight was unremarkable, and the pilot returned to the lake to land the airplane. The pilot performed a “normal” landing; however, when the airplane touched down, it veered to the left, nosed over, and came to rest in the water. The pilot and passengers escaped without incident.
According to a passenger, the airplane departed the lake and it was a “smooth” flight. When they returned to the lake to land, the “rear of the floats touched the water followed by a small hop.”
According to a witness who was on the lake at the time of the accident, the airplane approached the lake “hot” and “hit the water hard.” He watched the airplane bounce about 10 feet into the air and then impact the water again. Then, the wing tip struck the water and the airplane nosed over.
A post-accident examination of the airframe, by an FAA inspector, revealed that the bottom of the left float skin was partially separated along a rivet line. In addition, the left float was bent in a positive direction, about 20 degrees. The wings, rudder, and fuselage were substantially damaged in the accident sequence. Flight control continuity was confirmed from the cockpit to all control surfaces and the four landing gear tires were in the retracted position.
Sections of the left float skin were sent to the NTSB Materials Laboratory for further examination. The fracture surfaces were examined visually and exhibited a rough texture with a dull luster. No evidence was noted of corrosion on the fracture surfaces. Overall, the fracture surfaces were consistent with failure from overstress on a thin-walled structure.
The NTSB determines the probable cause(s) of this accident as follows: The pilot’s improper landing flare, which resulted in a hard landing and subsequent damage to the left float.