Boeing announced another contract to remanufacture AH-64D Apache attack helicopters to the AH-64E Guardian version for the U.S. Army.

The latest deal is worth $1.5 billion to the company and covers another 117 helicopters, plus Longbow radar crew trainers, logistical support and spares. It brings the total number of AH-64Es under contract for the U.S. Army to 290, including new-builds, with a further 300 planned by the service.

The AH-64E is a substantial modification, including new GE T700-701D engines, composite rotors, a new transmission, a modified driveshaft, new datalinks and a new mission computer. The Guardian also adds maritime modes to the Longbow radar. The first examples went operational with the U.S. Army in 2014.

India, Indonesia, Korea, Qatar, Saudi Arabia, Taiwan and the UK are confirmed export customers for the AH-64E. The UK has not yet announced whether it will have Boeing remanufacture 50 of its Apaches at Mesa, Ariz., or whether the work will be performed in the UK by the Yeovil facility of AgustaWestland (now Finmeccanica), where its original fleet of 67 WAH-64Ds was license-built. A notification to Congress last August valued the former option at $3 billion. The UK said it would decide by June this year.