After reviving deliveries of the original K-Max helicopter last year, Kaman’s small engineering team is considering options for updating and improving the 20-year-old design of the heavy-lift aircraft.

Kaman re-launched the dormant programme three years ago, after receiving interest from customers in the aerial firefighting market, and handed over the first K-Max aircraft from its Bloomfield, Connecticut assembly line last July.

Since deliveries of a first lot of 10 production aircraft resumed, Kaman has seen a huge amount of interest in the unique helicopter – which features an intermeshing rotor system – from a variety of operators, including firefighting and oil and gas companies, says Drake Klotzman, general manager for Kaman's air vehicles and MRO division.

Interest extends well beyond the forestry operators that accounted for the bulk of the 38 K-Max aircraft deliveries during the original 2008-2013 production run.

Discussions with buyers for a second lot of 10 production aircraft are now in progress, Klotzman says, with a third lot of sales expected to follow.

As demand has widened and stabilised, Kaman is now looking to expand the capabilities and performance of the original K-Max.

Options for upgraded systems are extensive, he says, including more power, improved avionics and structures and advances in autonomy.

K-Max aircraft are now delivered with refurbished Honeywell T53 turboshaft engines, but new propulsion systems may be considered.

The US Marine Corps deployed two K-Max aircraft modified with autonomous controls by Lockheed Martin to Afghanistan in 2009, to ferry cargo to remote operating bases.

Kaman is considering new ways to introduce autonomy in the K-Max cockpit for foreign military operators, but in a less expensive package, Klotzman says.