Boeing has updated a proposal to develop a growth version of the CH-47 Chinook featuring new engines and dynamic components to increase maximum gross weight by up to 20%, to 27,300kg (60,000lb). However, US army programme officials and the manufacturer view the business case for the heavier tandem rotor differently. The army is interested in the updated growth design, but only as a fall-back option in case the Joint Heavy Lift (JHL) programme now under study is rejected in fiscal year 2008, says Col William Crosby, the army’s Chinook programme manager. In that scenario, the army wants to have a lower-cost and less technologically ambitious alternative ready to enter development.