1. Aviation fuel (a) Use of unleaded aviation gasoline The Administrator of the Federal Aviation Administration (in this section referred to as the Administrator ) shall allow the use of an unleaded aviation gasoline in an aircraft as a replacement for a leaded gasoline if the Administrator— (1) determines that the unleaded aviation gasoline qualifies as a replacement for an approved leaded gasoline; (2) identifies the aircraft and engines that are eligible to use the qualified replacement unleaded gasoline; and (3) adopts a process (other than the traditional means of certification) to allow eligible aircraft and engines to operate using qualified replacement unleaded gasoline in a manner that ensures safety. (b) Timing The Administrator shall adopt the process described in subsection (a)(3) not later than 180 days after the later of— (1) the date on which the Administration completes the Piston Aviation Fuels Initiative; or (2) the date on which the American Society for Testing and Materials publishes a production specification for an unleaded aviation gasoline. (c) Other means and methods Any other existing regulatory mechanism by which the use of an unleaded aviation gasoline can be approved, either directly, or by a Supplemental Type Certificate for individual aircraft and engines or by use of an Approved Model List Supplemental Type Certificate providing coverage for all, or substantially all, of the entire fleet of aircraft and engines identified in the Federal Aviation Administration databases, shall continue to be fully available as a means of approving and bringing an unleaded aviation gasoline into general use in the United States. Such existing regulatory mechanisms shall not be further conditioned on the success, failure, or timing of the progress of the Piston Aviation Fuels Initiative, nor dependent upon a specification approved by the American Society for Testing and Materials.