Special Conditions: Preferred Improvements, LLC, Boeing Model DC3C Airplanes; Rechargeable Lithium Batteries

These special conditions are issued for Boeing Model DC3C airplanes as modified by Preferred Improvements, LLC. These airplanes will have a novel or unusual design feature when compared to the state of technology envisioned in the airworthiness standards for transport category airplanes. This design feature is rechargeable lithium ion backup battery packs installed on the airplanes. The applicable airworthiness regulations do not contain adequate or appropriate safety standards for this design feature. These special conditions contain the additional safety standards that the Administrator considers necessary to establish a level of safety equivalent to that established by the existing airworthiness standards.