((a)) ** Study; proposed standards; hearings; issuance of regulations**

((1)) Within 90 days after , the Administrator shall commence a study and investigation of emissions of air pollutants from aircraft in order to determine—

((A)) the extent to which such emissions affect air quality in air quality control regions throughout the United States, and

((B)) the technological feasibility of controlling such emissions.

((2))

((A)) The Administrator shall, from time to time, issue proposed emission standards applicable to the emission of any air pollutant from any class or classes of aircraft engines which in his judgment causes, or contributes to, air pollution which may reasonably be anticipated to endanger public health or welfare.

((B))

((i)) The Administrator shall consult with the Administrator of the Federal Aviation Administration on aircraft engine emission standards.

((ii)) The Administrator shall not change the aircraft engine emission standards if such change would significantly increase noise and adversely affect safety.

((3)) The Administrator shall hold public hearings with respect to such proposed standards. Such hearings shall, to the extent practicable, be held in air quality control regions which are most seriously affected by aircraft emissions. Within 90 days after the issuance of such proposed regulations, he shall issue such regulations with such modifications as he deems appropriate. Such regulations may be revised from time to time.

((b)) ** Effective date of regulations** Any regulation prescribed under this section (and any revision thereof) shall take effect after such period as the Administrator finds necessary (after consultation with the Secretary of Transportation) to permit the development and application of the requisite technology, giving appropriate consideration to the cost of compliance within such period.

((c)) ** Regulations which create hazards to aircraft safety** Any regulations in effect under this section on , or proposed or promulgated thereafter, or amendments thereto, with respect to aircraft shall not apply if disapproved by the President, after notice and opportunity for public hearing, on the basis of a finding by the Secretary of Transportation that any such regulation would create a hazard to aircraft safety. Any such finding shall include a reasonably specific statement of the basis upon which the finding was made.August 7, 19771977-08-07