Section 77.29 - Evaluating aeronautical effect(a) The FAA conducts an aeronautical study to determine the impact of a proposed structure, an existing structure that has not yet been studied by the FAA, or an alteration of an existing structure on aeronautical operations, procedures, and the safety of flight. These studies include evaluating: (1) The impact on arrival, departure, and en route procedures for aircraft operating under visual flight rules;(2) The impact on arrival, departure, and en route procedures for aircraft operating under instrument flight rules;(3) The impact on existing and planned public use airports;(4) Airport traffic capacity of existing public use airports and public use airport development plans received before the issuance of the final determination;(5) Minimum obstacle clearance altitudes, minimum instrument flight rules altitudes, approved or planned instrument approach procedures, and departure procedures;(6) The potential effect on ATC radar, direction finders, ATC tower line-of-sight visibility, and physical or electromagnetic effects on air navigation, communication facilities, and other surveillance systems;(7) The aeronautical effects resulting from the cumulative impact of a proposed construction or alteration of a structure when combined with the effects of other existing or proposed structures.(b) If you withdraw the proposed construction or alteration or revise it so that it is no longer identified as an obstruction, or if no further aeronautical study is necessary, the FAA may terminate the study.