On September 9, 1997, at 1730 mountain daylight time, a Piper PA-18-150, N91019, registered to and operated by the pilot as a 14 CFR Part 91 personal flight, collided with a fence post and subsequently landed hard and collapsed the landing gear at a private airstrip located ten miles east of Mackay, Idaho. Visual meteorological conditions prevailed at the time and no flight plan was filed for the local flight. The airplane was substantially damaged. The private pilot and his passenger were not injured. The pilot reported that he was landing to the north on the grass airstrip. A four foot high fence crosses perpendicular to the approach end of the airstrip. The pilot reported that while on short final for the short field landing, the airplane settled and struck the fence. The airplane then landed hard just beyond the fence. The landing gear collapsed and the right wing tip dragged on the ground.