First deliveries of Boeing 737 airborne early warning and control system aircraft to launch customer Australia have been hit by a further four-month delay.
The US manufacturer says the initial operational capability date for the first pair of aircraft under Australia's Wedgetail surveillance programme has slipped to July 2009, due to the need to "extend validation and flight test".
The project - which had already been running around two years late - has also encountered delays in development of the aircraft's BAE Systems Australia-supplied electronic support measures package.
The first two aircraft will arrive without electronic warfare systems but will be available for training. They are due to be equipped with EW systems in early 2010, achieving full operational capability by the end of that year with the arrival of the remaining four aircraft on firm order.
"We've been having some technical challenges," says Chris Chadwick, Boeing's president of precision engagement and mobility systems. "We've been working very closely with our suppliers BAE and Northrop [Grumman] and we see a light at the end of the tunnel," he adds.
"It's a very demanding requirement. We're still working the ESM challenges so we're going to be working closely with BAE, with some Boeing executives in-country working hand-in-hand with them to bring this home in the July  timeframe."
BAE Systems Australia says: “The ESM system has been integrated to a number of Wegetail aircraft and recently been flight tested. First indications are the system has performed its functions well, with more flight testing to complete. We continue to work through the delivery phase of the programme.”
Boeing says the latest problems on the Wedgetail programme are not expected to have an impact on 737 AEW&C acquisitions by South Korea and Turkey.
Australia's first two Wedgetail aircraft underwent modification - including the installation of Northrop's multirole electronically scanned array radar, ventral fins and mission equipment - in the USA, with the remainder being modified by Boeing Australia at Royal Australian Air Force base Amberley, Queensland.
Aircraft profile: Boeing 737