; 130 Stat. 2696) for Hanscom Air Force Base, Massachusetts, for construction of a gate complex at the installation, the Secretary of the Air Force may construct a visitor control center of 187 square meters, a traffic check house of 294 square meters, and an emergency power generator system and transfer switch consistent with the Air Force’s construction guidelines. (b) Mariana Islands In the case of the authorization contained in the table in section 2301(b) of the Military Construction Authorization Act for Fiscal Year 2017 (division B of Public Law 114–328 ; 130 Stat. 2697) for acquiring 142 hectares of land at an unspecified location in the Mariana Islands, the Secretary of the Air Force may purchase 142 hectares of land on Tinian in the Northern Mariana Islands for a cost of $21,900,000. (c) Chabelley Airfield In the case of the authorization contained in the table in section 2902 of the Military Construction Authorization Act for Fiscal Year 2017 (division B of Public Law 114–328 ; 130 Stat. 2743) for Chabelley Airfield, Djibouti, for construction of a parking apron and taxiway at that location, the Secretary of the Air Force may construct 20,490 square meters of taxiway and apron, 8,230 square meters of paved shoulders, 10,650 square meters of hangar pads, and 3,900 square meters of cargo apron. (d) Scott Air Force Base The table in section 4601 of the Military Construction Authorization Act for Fiscal Year 2017 (division B of Public Law 114–328 ; 130 Stat. 2877) is amended in the item relating to Scott Air Force Base, Illinois, by striking Consolidated Corrosion Facility add/alter in the project title column and inserting Consolidated Communication Facility add/alter . 2306. Extension of authorizations of certain fiscal year 2015 projects (a) Extension Notwithstanding section 2002 of the Military Construction Authorization Act for Fiscal Year 2015 (division B of Public Law 113–291