Whether to reinstate the alternate engine program for the F-35 Lightning II fighter was a significant issue for Congress in FY2012, with implications for the defense budget, military capability in the future, and the division of power between Congress and the executive branch. The program was developing the General Electric/Rolls-Royce F136 engine as an alternative to the Pratt & Whitney F135 engine that currently powers the F-35. Successive Administrations proposed terminating the alternate engine program in the FY2007 through FY2010 budgets. Congress rejected these proposals and provided funding, bill language, and report language continuing the program. In FY2011, the Administration's budget submission again proposed to terminate the alternate engine program, and Congress eliminated funding for the program in the final FY2011 DOD and Full-Year Continuing Appropriations Act. On December 2, 2011, General Electric and Rolls-Royce announced that they were ending development of the F136 engine, terminating the F-35 engine competition. On October 26, 2001, the Department of Defense (DOD) selected the single-engine Lockheed Martin F-35, powered by the Pratt & Whitney F135 engine, as the winner of its Joint Strike Fighter (JSF) competition. DOD expects to buy 2,456 JSFs for the Air Force, Navy, and Marine Corps. In FY1996, Congress required development of an alternate engine for the F-35. This became the F136, based on an engine created by the team of General Electric and Rolls-Royce for the unsuccessful McDonnell Douglas JSF candidate. The F135 and F136 engines were designed to be used interchangeably, without modification to the F-35 airframe. In FY2007, the Administration proposed terminating the alternate engine program "because development of the main engine was progressing well and analysis indicated that savings from competition would not be offset by high upfront costs." Congress subsequently restored funding for the program, along with directive bill and report language requiring DOD to continue the program in future years. Administration-proposed terminations in FY2008, FY2009, and FY2010 were also rejected by Congress. Subsequently, in FY2011, the 112 th Congress deleted funding for the program. DOD formally terminated the alternate engine program on April 25, 2011. Supporters of the Administration's proposal to terminate the alternate engine program argue the following: Developing and procuring a second engine for the F-35 would add billions of dollars to the cost of the F-35 program by roughly doubling engine development costs and halving engine production economies of scale. Such a cost increase would reduce the number of F-35s that could be procured within a given total amount of F-35 acquisition funding, forcing cuts in future capabilities and force structure. An official from the F-35 program office stated that the reduction in F-35 procurement over the next five years might total 50 to 80 aircraft. Procuring a second engine would increase F-35 life-cycle operation and support (O&S) costs by requiring DOD to maintain two engine maintenance and repair pipelines. Supporting two engines on aircraft carriers would be particularly challenging due to limited space and facilities. Having a second engine is not needed to sustain international interest in the F-35, because the most significant potential foreign buyers are already committed to the F-35 program, and because committed and potential buyers already have several significant reasons to be interested in the F-35, starting with the aircraft's capabilities, procurement cost, and operating and support cost. Congress already accepts the risk of using single designs across fleets, both in powerplants and airframes. Many other aircraft types in the U.S. inventory use one engine design across the fleet. Procurement of a single airframe design also carries the risk of fleet grounding if there is a flaw in the design (as has occurred in the past), yet those risks are acceptable to Congress and DOD. The same risk logic should apply to F-35 engines. Development, testing, and production of the F135 have reached the point where it is no longer necessary to hedge against the possibility of technical problems in the F135 engine by pursuing an alternate engine program as a backup. The causes of F135 test failures in 2007 and 2008 have been identified and fixes are being implemented. Opponents of the Administration's proposal to terminate the alternate engine program argue the following: The Administration's proposal to terminate the alternate engine program does not comply with Section 213 of the FY2008 defense authorization act ( H.R. 4986 / P.L. 110-181 of January 28, 2008), which states: "Of the funds appropriated pursuant to an authorization of appropriations or otherwise made available for fiscal year 2008 or any year thereafter, for research, development, test, and evaluation and procurement for the Joint Strike Fighter Program, the Secretary of Defense shall ensure the obligation and expenditure in each such fiscal year of sufficient annual amounts for the continued development and procurement of 2 options for the propulsion system for the Joint Strike Fighter in order to ensure the development and competitive production for the propulsion system for the Joint Strike Fighter." Given that F-35s are to constitute the vast majority of the country's strike fighters, it would be imprudent to have all those strike fighters powered by a single type of engine, since a problem with that engine could force the grounding of the entire F-35 fleet. Having a second engine in production (or ready for production) would permit DOD to use competition (or the threat of competition) in procuring and supporting F-35 engines, which could reduce F-35 engine procurement and O&S costs compared to what would be achievable in a sole-source procurement, offsetting the additional costs associated with developing, procuring, and supporting a second engine. Competition (or the threat of competition) would also promote better engine performance, increased engine reliability, and improved contractor responsiveness. Having two F-35 engine production lines in operation would also permit F-35 engine production to be more quickly surged to higher levels if needed to respond to a change in the strategic environment, and preserve a potential for maintaining effective competition in the development and procurement of future tactical aircraft engines, particularly if F-22 and F/A-18E/F production ends. Having a second engine in production would help sustain international interest in the F-35 program, maximizing F-35 exports. Potential foreign buyers would be more inclined to purchase the F-35 if they had a choice regarding the aircraft's engine, and if they believed that competition (or the threat of competition) in engine production was holding down the engine portion of the F-35's total cost. These are the most common questions received by CRS concerning the F-35 alternate engine program: The alternate engine program was terminated by DOD on April 25, 2011. Subsequently, DOD ordered all of the tooling and engines produced under the contract to be delivered back to DOD. A spokesman for the alternate engine's builder "noted that more than $200 million in F136 hardware is located in 17 facilities, including 'nine engines under various stages of assembly.'" On December 2, 2011, General Electric and Rolls-Royce announced that they were ending their self-funded development of the F136 engine. A copy of their statement on termination appears as Appendix C . Pratt & Whitney, the incumbent engine maker, received a total of $7.3 billion in funding during the period FY1994-FY2009 for work relating to the F-35 program. This figure included funding for work performed for the Boeing concept for the JSF (a concept that was not selected to go forward.) The $7.3 billion also includes $6.1 billion received during the period FY2002-FY2009 for F135 System Development and Demonstration (SDD) work. The estimated cost of the F135 SDD contract increased from $4.8 billion at contract award in 2001 to $6.7 billion as of September 2009. Approximately $0.8 billion of the increase is cost growth; the remaining $1.1 billion or so reflects an increase in the scope of work to be performed. The General Electric/Rolls-Royce alternate engine team received a total of $2.4 billion during the period FY1995-FY2009. This total includes $1.7 billion for SDD work for the F136 engine during the period FY2005-FY2009. The F136 team's effort did not include design, development, test, or delivery of STOVL Lift System components and exhaust systems, which were developed and provided under the F135 Pratt & Whitney SDD contract. The F136 SDD contract consequently included fewer test hours and fewer ground test engines. A discussion of technical issues follows in the " Engine Development Issues " section of the report, below. Between the beginning of FY2011 and enactment of the final FY2011 DOD and Full-Year Continuing Appropriations Act on April 15, 2011, the government operated under a series of continuing resolutions (CRs). In light of the Administration's stated opposition to further funding of the alternate engine program, some members of Congress questioned the status of the program during the period of a CR. CRs prohibit spending on new starts or on procurement rates above FY2010 levels. P.L. 111-242 , the CR effective through March 4, 2011, set DOD spending at a "rate of operations" consistent with the FY2010 DOD Appropriations Act ( P.L. 111-118 ) for the base budget, the FY2010 Omnibus for military construction levels set in P.L. 111-117 with reductions for BRAC funding not requested in FY2011, plus war funding provided in Title IX of the FY2010 DOD Appropriations Act and in the FY2010 Supplemental ( P.L. 111-212 ).