On April 17, 1999, approximately 1700 Pacific daylight time, a Beech 35-C33, N1310A, experienced a landing gear collapse on the runway while performing a touch-and-go landing on runway 30 at Portland-Hillsboro Airport, Hillsboro, Oregon. The aircraft subsequently slid to a stop on the runway on its belly, sustaining substantial damage. The private pilot-in-command and one passenger, his wife, were not injured. Visual meteorological conditions prevailed for the 14 CFR 91 local personal flight out of Portland-Hillsboro, and no flight plan had been filed. The pilot reported he lowered the gear on downwind at midfield, and rechecked it on base and final. The pilot stated that all gear indicated down. The pilot reported that the approach (performed with 20 degrees of flaps) and touchdown were normal. The pilot stated that the main gear touched down normally but that he had no memory of nose wheel touchdown. He stated: ...The nose dropped below normal for landing roll-out [and] I sensed something was wrong. I applied power to attempt take-off but was too slow of speed [and] rapidly slid to stop in nose down position on centerline of runway. The landing gear appeared to be in a semi- retracted or collapsed position. The pilot stated in a telephone interview with the NTSB investigator-in-charge that the entire accident sequence happened in about 5 seconds, and that he did not remember reaching for or operating any switches (such as gear or flaps) at the time the accident happened. The pilot reported to the NTSB that he had not logged any pilot time in the 90 days preceding the accident. FAA inspectors who examined the airplane after the accident reported to the NTSB that they found abrasion damage to the airplane's main landing gear doors, as well as overstress damage to the nose landing gear consistent with the nose gear being forcibly pushed back up into the nose wheel well. The FAA inspectors also reported that in a post-accident test, a successful manual extension of the main landing gear was accomplished, but that the nose gear did not extend during this test. The aircraft's last annual inspection was on March 10, 1999, approximately 1 month and 15 flight hours before the accident. The airframe total time at the time of the accident was 7,067 hours. According to the aircraft logbooks, maintenance to the landing gear performed in conjunction with the March 10, 1999, annual inspection included: replacement of nose gear door hinge bushings and steel inserts; replacement of nose gear door actuator shaft rods (002-410042-1) along with both right and left hand gussets (002-410000-29 and -27); servicing of shimmy dampener; replacement of left inboard main gear wheel bearing (13889) and cup (13836) and all felts (154-00800); removal and rebuilding of right main landing gear strut, installation of new top snap ring (RRN237C), O-rings (AN6230-B5/M83461-1-227 and MS28775-328), felt (35-815247-9), and scraper (CR 504271); and removal, cleaning, and lubrication of trunnion and torque knee bushings. The March 10, 1999, logbook entry also indicated that rivets, forward wing spar-to-belly skin, nose gear opening and right aileron hinge brackets were replaced at that time. Portland-Hillsboro runway 30 is a 6,600 by 150 foot asphalt-surface runway, and is equipped with a visual approach slope indicator (VASI). Winds at Portland-Hillsboro were reported as variable at 3 knots at 1653.