PAUL LEWIS / MONTREAL

The US Army's proposed restructured development plan for the Boeing Sikorsky RAH-66 Comanche has cleared its penultimate hurdle following approval by the Army System Acquisition Review Council. A green light from the Defense Acquisition Board (DAB) is due in August after independent analysts complete cost estimates.

The $6.6 billion development programme now hinges on DAB approval. The troubled programme has been restructured five times since 1983, while development costs have doubled.

Additional details about the proposed spiral development plan were unveiled at the American Helicopter Society forum in Montreal last week by US Army Aviation deputy programme executive Paul Bogosian. A total of 204 RAH-66s will be completed to an initial Block 1 reconnaissance and attack configuration, before production switches to an enhanced attack-mission Block 2 standard.

Block 1 is due to enter service from September 2009. It will have the Longbow fire-control radar and a full night-vision pilotage and electro-optical sight mission suite, internal weapons such as the Lockheed Martin AGM-114 Hellfire anti-tank missiles, and Link 16 datalink, but not the Joint Tactical Radio System. It will also feature an enhanced position locating reporting system and airborne control of unmanned air vehicles, both add- on capabilities that contributed significantly to the cost escalation.

Block 2 introduces weight reductions and a phased recapitalisation of the fleet. Added capabilities will include an air-to-air missile, a wing for mounting external fuel tanks and munitions and full cockpit sensor fusion. A follow-on Block 3 will add mission capabilities.

Meanwhile, the US Army has contracted Sandia National Laboratories to validate an extra package of recapitalisation components for the Boeing AH-64A/D Apache, in addition to the repair and sustainability solutions in progress. The list of identified items includes the turret housing for targeting and piloting sensors, wing pylons and display assemblies.

The first internal fuel/30mm ammunition "combo packs" will be deployed in August, replacing the 1,200-round magazine with a 380 litre (100US gal) fuel tank and 300 rounds, adding 1h to the helicopter's 2h endurance.

Source: Flight International