The US State Department is to purchase up to 110 modernised S-61T helicopters for its worldwide passenger and cargo transport missions.

As part of the Sikorsky S-61T programme the new helicopters will upgrade existing S-61/H-3 to increase performance in hot and high operating conditions.

Upgrades include composite main rotor blades, a glass cockpit and a modular wiring harness to improve aircraft supportability.

The S-61Ts have also been equipped with 1,200lb of added lift capability, enhanced speed, and features to reduce pilot fatigue and maintenance requirements for increased safety.

The helicopters will provide an alternative to the Pentagon’s current Russian helicopters.

The first four of the purchased helicopters will serve the US Embassy in Afghanistan.