A Tecnam P2006T was unable to maintain altitude on one engine when a flight instructor tried for a freeway landing in Larkspur, Colorado, last June 16, according to a preliminary report from the NTSB. The instructor and student took off just after 6 a.m. in the four-place twin, which is powered by 100-horsepower Rotax 912 engines, from Centennial Airport in Englewood. They did five full-stop landings there before heading to Perry Park Airport in Larkspur to practice single-engine procedures.