On May 12, 1997, at 0630 hours Pacific daylight time, a Piper PA-32R-300, N3609Q, was substantially damaged when the upper engine cowling came loose, separated from the nose section, and lodged on the horizontal stabilizer. The cowling remained on the stabilizer until after landing and then fell off onto the runway during the landing rollout. The solo commercial pilot was not injured. The flight departed Burbank Airport, Burbank, California, for an on-demand air taxi cargo flight to Mammoth Lakes, California, with intermediate stops planned at Lancaster and Inyokern. Instrument meteorological conditions prevailed and an IFR flight plan was filed. According to the aircraft maintenance records, this was the first flight after the aircraft underwent a 50-hour routine inspection during which the top cowl was removed and then reinstalled. The last inspection that specifically requires the cowling and its fasteners to be inspected for serviceability was accomplished on January 28, 1997. The aircraft had been flown 134.7 hours since that date. The aircraft had a total time 6,711 hours when it departed on May 12, 1997. The Federal Aviation Administration inspector stated that, although only three cowl fasteners could be found, none of them appeared to be damaged or excessively worn. He also stated that the two front alignment pins that attach to the lower cowl were missing.