WASHINGTON — The Pentagon has reached an agreement with Pratt & Whitney for the ninth low rate initial production (LRIP) lot of F135 engines, which power the F-35 joint strike fighter.

The agreement, worth an estimated $1.4 billion over the life of the production lot, covers 66 engines, as well as spares, extra parts, and support from the Connecticut-based engine manufacturer. Specifically, the breakdown is 53 conventional takeoff and landing engines, used in the F-35A and F-35C models, and 13 short takeoff and vertical landing models used for the F-35B model.

The engine lot also includes engines for five international partners and customers: Italy, Norway, Israel, Japan and the United Kingdom. Engines under this contract should begin delivery before the end of the year, according to a Pratt statement.

The company also notes it expects to be on contract for LRIP 10 by the end of this month.

The agreement is not a surprise, as the Pentagon said it had an agreement in principal with Pratt in January. At the time, Lt. Gen. Chris Bogdan, the F-35 program head, said that unit prices the CTOL engines dropped 3.4 percent between LRIP 8 and LRIP 10, while unit prices for the STOVL engines decreased 6.4 percent.

"The latest agreement with the F-35 Joint Program Office continues a reduction in costs associated with engine production, and demonstrates our commitment in providing affordable and dependable propulsion for the global F-35 program," said Mark Buongiorno, Pratt's vice president for the F135 Engine Program, in the statement.

Twitter: @AaronMehta