CAPE CANAVERAL, Fla. (AP) — NASA’s little Mars helicopter is safely on the ground following a wild, lurching ride caused by a navigation timing error. The space agency reported the trouble Thursday, almost a week after it occurred during the helicopter’s sixth test flight. It was the first major problem for the experimental helicopter named Ingenuity since it took to the Martian skies last mont. The helicopter’s chief pilot at NASA’s Jet Propulsion Laboratory says the craft began tilting back and forth as much as 20 degrees and suffered power consumption spikes, before managing to land within 16 feet of its intended touchdown site.