The provision of Approach Control Service was established pursuant to the provisions stated in paragraph (2) of Section 32 of the Civil Aeronautics Act (R.A. No. 776 series of 1952 as amended by Presidential Decree 884, 1278 and 1462 and Executive Order 546) in compliance with the provision set forth by Annex 11 to the Convention of International Civil Aviation, International Standards and Recommended Practices.