AD FAA-2011-1161

We are adopting a new airworthiness directive (AD) for certain Cessna Aircraft Company (Cessna) Model 525C airplanes. This emergency AD was sent previously to all known U.S. owners and operators of these airplanes. This AD requires replacing certain lithium-ion batteries installed as the main aircraft battery with either a Ni-Cad or a lead acid battery. This AD was prompted by a report of a battery fire that resulted after an energized ground power unit was connected to one of the affected airplanes equipped with a lithium-ion battery as the main aircraft battery. We are issuing this AD to correct the unsafe condition on these products.