On April 24, 2001, at 0943 Pacific daylight time, a Cessna 172S, N435SP, registered to a private owner, and being flown by a private pilot accompanied by a commercially rated check pilot (flight instructor), was substantially damaged when a Canadian goose impacted the left wing leading edge damaging the wing spar while the aircraft was on short final to runway 15 at the Renton Municipal airport, Renton, Washington. Both pilots were uninjured and the aircraft was successfully landed with no further damage. Visual meteorological conditions existed and no flight had been filed. The flight, which was being conducted as a checkout in the aircraft for the Boeing Employees Flying Association (lessor of the aircraft), was operated under 14 CFR Part 91, and was local in nature. The pilot-in-command (left seat) reported that he and the flight instructor (right seat) were conducting the first touch-and-go landing associated with the PIC's sixth month check ride. He reported that: "The airplane was over the numbers, landing to the South on runway 15, at an altitude of less than 50 ft AGL, flaps 30 degrees, throttle at or near idle, when two Canada geese came into the pilots field of view, flying from right to left. The geese were lower than the aircraft and shielded from the pilots' view by the aircraft until they were past the nose. They appeared to be gaining altitude relative to the aircraft. Being relatively close to the ground, and at an airspeed of approximately 60KTS, the pilot elected to not take any evasive action, but rather be prepared to control the airplane in the case of a collision. The birds passed out of the pilots' field of view. He heard and felt a 'thump,' but did not experience any difficulty in controlling the airplane. He completed the landing and exited the runway."