US ARMY PLANS to upgrade its ageing Boeing Chinook CH-47D fleet have received a fillip from Congressional supporters, with funding being made available to begin the programme earlier than expected.

The improved-cargo-helicopter (ICH) refurbishment project also recently won the endorsement of the US Army leadership, which approved the ICH's critical Operational Requirements Document on 11 October.

The US Army says that it needs in the order of $3.3 billion to undertake the ICH programme, including $70-80 million in research-and-development funding and $690 million for long-lead production between fiscal years 1998 and 2003.

The project will be initiated sooner, however, since US lawmakers added $17.7 million to the Pentagon's fiscal year 1997 budget to begin ICH work.

They also provided funds to complete development and begin procuring AlliedSignal Engines T55-GA-714A powerplants, which offer 22% more power than does the current T55-L-712.

Two pre-production ICH Chinooks will be built in the R&D programme. Twelve CH-47D ICHs will follow, and 24 Chinooks will be modified each year until all 300 are modernised by 2015, when the Joint Transport Rotorcraft (JTR) begins to be fielded. The ICHs will stay in service until 2032.

More twin-engined CH-47Ds could be upgraded should there be delays to the planned JTR, which is to replace the CH-47D and Sikorsky CH-53E. The US Army's fleet includes 431 CH-47Ds, 11 MH-47Ds and 25 MH-47Es.

One-third of the $3.3 billion would be used to install the -714A engine, with the rest being spent on airframe and avionics improvements and vibration-reduction.

The $17.7 million budget "plus-up" will allow Boeing Helicopters to continue development studies, define the configuration and work on risk mitigation.

Boeing Helicopters is preparing a rebuilt CH-47D, which incorporates two-thirds of the ICH improvements, including -714A engines, for 66h of flight tests at Fort Rucker, Alabama, between November of this year and March 1997.

Meanwhile, AlliedSignal Engines officials believe that the US Army may need an engine upgrade beyond the 3,630kW (4,870shp) -714A. The 4250kW T55 growth engine would have some advanced technologies being developed in the Pentagon's classified Joint Technology Advanced Gas Generator programme.

Source: Flight International