Senators today voted to freeze spending on the General Electric/Rolls-Royce F136, the second engine under development for the Lockheed Martin F-35 Joint Strike Fighter (JSF) programme.

The Senate voted to reject an amendment that would have restored more than $600 million to continue development of the F136 and buy the first four production units. Senators also passed another amendment that would block any further spending on the F136 unless Secretary of Defense Robert Gates certifies that the alternate engine programme will both reduce costs and improve the readiness of the F-35 fleet.

The vote marks the second major setback for opponents of the Obama administration’s goal to reform the way the Department of Defense and Congress prioritizes and spends money on weapons. The Senate also has voted to strip $1.75 billion to buy seven more F-22s from the Fiscal 2010 defence authorisation bill.

But the Senate’s move is not the last step in the budget process. The House of Representatives has passed a bill that includes continued funding for the F136. The House committee also criticized cost overruns experienced to date by the Pratt & Whitney F135 engine programme.

House and Senate members will meet later this month to reconcile differences between the two bills.

The Senate’s negative vote on the F136 also marks the end a four-year-old process. Since 2006, the DOD has removed funds for the F136 in its budget request, but the money was restored by the programme’s allies in Congress.

The process was repeated again this year, despite a veto threat issued by the Obama Administration over funding for both F136 and F-22s.

The F136 now faces a budget freeze as it nears the end of its development phase and transitions into low-rate production. The first F136 began ground testing in January, and it is scheduled to fly in 2011, which is slightly behind schedule..