The Netherlands will spend over $1 billion to remanufacture and upgrade its 28 Boeing AH-64D Apache attack helicopters to the AH-64E standard.

A letter of agreement for the Foreign Military Sales (FMS) upgrade deal was signed US and Dutch officials, says the US Defense Security Cooperation Agency.

In February the DSCA said that the $1.19 billion package will see upgrades to the helicopters’ General Electric T700 engines, fire control and targeting systems, and other equipment. The deal will also include training for Dutch personnel, which will be undertaken at Fort Hood, Texas.

Key contractors for the work are Boeing and Lockheed Martin.

Flight Fleets Analyzer shows that the average age of the Dutch Apache fleet is 17.4 years, with an age range of 16.1 to 20.3 years.

The aircraft have seen extensive use, including missions in Afghanistan and Mali. Earlier this year, the Dutch defence ministry warned that the fleet was starting to suffer technical shortcomings, compromising the rotorcrafts’ utility in high threat environments.