WASHINGTON -- Saudi Arabia is poised to buy nearly 50 CH-47F Chinook cargo helicopters, the largest foreign military sale for Chinooks to date, and it would help shore up a production gap in the US Army's procurement program, according to a service spokesman.

Should the sale move forward, Saudi Arabia would acquire 48 CH-47Fs and 112 T-55 engines, as well as embedded GPS inertial navigation systems, Common Missile Warning Systems (CMWS) and M240H 7.62 machine guns along with a host of other bells and whistles.

The total sale is estimated at $3.51 billion, according to a Defense Security Cooperation Agency notification posted late last week.

While there may be potential for some cost savings, Paul Stevenson, an Army Program Executive Office Aviation spokesman, said the sale would benefit not just the unit cost of the helicopters, but would help maintain an active production line and industrial base during the gap between the end of the CH-47F Block I production in 2018 and the initiation of CH-47F Block II production in 2021.

Boeing is the prime manufacturer for the Chinook helicopter; Honeywell Aerospace is the prime contractor for the T-55 engine.

The key objective for the Chinook Block II program is to restore payload capacity lost over the years. The Army is eyeing a potential new engine for the helicopter, but there is currently no requirement for it. Upgrades to the electrical system, transmission and rotor system are also in store.

The sale to Saudi Arabia would expand the international fleet of Chinook operators to 20 countries.

Also last week, the State Department announced another possible arms sale to the United Arab Emirates for AH-64E Apache attack helicopters, valued at around $3.5 billion. The UAE wants 28 remanufactured versions and nine new AH-64Es.

Boeing is also the prime contractor for the Apache helicopter.