On October 5, 2002, approximately 1345 Pacific daylight time, a Curtiss Wright Travel Air 4000, N4949, registered to and being flown by a commercial pilot, and operated by Tillamook Air Tours, sustained substantial damage during the landing roll when the aircraft's left main gear collapsed and the aircraft nosed over at the Tillamook airport, Tillamook, Oregon. The pilot and two passengers were uninjured. The pilot reported the weather conditions as "calm and cool" and no flight plan had been filed. The 14 CFR 91 sightseeing flight originated from the Tillamook airport approximately 1300. The pilot reported that he preflighted the aircraft and then departed Tillamook airport on a 45-minute local sightseeing flight with two passengers. Upon landing on runway 31 the pilot noted the aircraft began pulling left and he heard a "thumping" sound. The aircraft departed the west side of the runway rolling into a grassy area and then nosed over (refer to photograph 1). The pilot also reported that company personnel on the ground at Tillamook airport observed the aircraft prior to landing and noted the left main gear "hanging down" but were unable to contact the pilot by radio. The pilot reported that the wheels are not visible from the rear cockpit in flight. Two inspectors assigned to the Federal Aviation Administration's (FAA) Hillsboro, Oregon, Flight Standards District Office conducted post-accident inspection of the aircraft. The examination revealed that the weld between the left-right main wheel axle and the left wheel "V" strut had fractured (refer to photograph 2). The FAA inspectors interviewed the individual who restored the 1928 vintage aircraft and determined that the wheel axle to gear strut welds (left and right) were original welds and had not been replaced or altered during the restoration process.