36 C.F.R. § 2.17 : Parks, Forests, and Public Property — NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR — RESOURCE PROTECTION, PUBLIC USE AND RECREATION — Aircraft and air delivery

(a) The following are prohibited:
(1) Operating or using aircraft on lands or waters other than at locations designated pursuant to special regulations.
(2) Where a water surface is designated pursuant to paragraph (a)(1) of this section, operating or using aircraft under power on the water within 500 feet of locations designated as swimming beaches, boat docks, piers, or ramps, except as otherwise designated.
(3) Delivering or retrieving a person or object by parachute, helicopter, or other airborne means, except in emergencies involving public safety or serious property loss, or pursuant to the terms and conditions of a permit.
(b) The provisions of this section, other than paragraph (c) of this section, shall not be applicable to official business of the Federal government, or emergency rescues in accordance with the directions of the superintendent, or to landings due to circumstances beyond the control of the operator.
(c)
(1) Except as provided in paragraph (c)(3) of this section, the owners of a downed aircraft shall remove the aircraft and all component parts thereof in accordance with procedures established by the superintendent. In establishing removal procedures, the superintendent is authorized to:
(i) Establish a reasonable date by which aircraft removal operations must be complete;
(ii) determine times and means of access to and from the downed aircraft; and
(iii) specify the manner or method of removal.
(2) Failure to comply with procedures and conditions established under paragraph (c)(1) of this section is prohibited.
(3) The superintendent may waive the requirements of paragraph (c)(1) of this section or prohibit the removal of downed aircraft, upon a determination that:
(i) The removal of downed aircraft would constitute an unacceptable risk to human life;
(ii) the removal of a downed aircraft would result in extensive resource damage; or
(iii) the removal of a downed aircraft is impracticable or impossible.
(d) The use of aircraft shall be in accordance with regulations of the Federal Aviation Administration. Such regulations are adopted as a part of these regulations.
(e) The operation or use of hovercraft is prohibited.
(f) Violation of the terms and conditions of a permit issued in accordance with this section is prohibited and may result in the suspension or revocation of the permit.

36 C.F.R. §2.17