; and (B) if the Secretary makes a determination to award a sole source contract for such procurement in order to meet the requirements established by the Commander of the United States Northern Command, not later than 14 days after making such determination, the Secretary shall submit to the congressional defense committees a notification of such determination, including the rationale for such determination. (2) Subsequent contracts The Secretary of the Air Force shall use competitive procedures for the award of a contract for the procurement of the third and any subsequent over-the-horizon radar systems under subsection (a). (3) Competitive procedures defined In this section, the term competitive procedures has the meaning given that term in section 3012 of title 10, United States Code. 139. Prohibition on availability of funds for retirement of KC–135 aircraft (a) Prohibition Except as provided in subsection (b), none of the funds authorized to be appropriated by this Act or otherwise made available for fiscal year 2024 for the Air Force may be obligated or expended to retire, or prepare to retire, a KC–135 aircraft. (b) Exception The prohibition under subsection (a) shall not apply to individual KC–135 aircraft that the Secretary of the Air Force determines, on a case-by-case basis, to be no longer mission capable and uneconomical to repair because of aircraft accidents, mishaps, or excessive material degradation and non-airworthiness status of certain aircraft. 140. Prohibition on reduction of KC–135 aircraft in PMAI of the reserve components (a) Prohibition None of the funds authorized to be appropriated by this Act or otherwise made available for fiscal year 2024 for the Air Force may be obligated or expended to reduce the number of KC–135 aircraft designated as primary mission aircraft inventory within the reserve components of the Air Force. (b) Primary mission aircraft inventory defined In this section, the term primary mission aircraft inventory has the meaning given that term in section 9062(i)(2)(B)