On May 18, 2003, about 1255 Pacific daylight time, an experimental owner built Monaghan Glasair, N271RP, ground looped while landing at Hayward Executive Airport (HWD), Hayward, California. The builder/owner/pilot was operating the airplane under the provisions of 14 CFR Part 91. The private pilot and one pilot rated passenger were not injured; the airplane sustained substantial damage. The personal cross-country flight departed Halfmoon Bay, California, about 1230 en route to Hayward, California. Day visual meteorological conditions prevailed, and no flight plan had been filed. The primary wreckage was at 37 degrees 39.56 minutes north latitude and 122 degrees 07.35 minutes west longitude. The pilot stated that he had tried to land at HWD on runway 28L but had executed a go-around. On his second approach to runway 28L, the airplane bounced, he lost directional control, and the airplane departed the runway to the left. He reported that just as the airplane bounced into the air, a gust of wind made the airplane weather vane to the left. Before he could correct, the airplane touched down and ground looped. The airplane departed the runway and came to rest in the grass area between runways 28R and 28L. The weather observation at HWD was reported at 1254 PDT as wind from 280 degrees at 10 knots.