In May 2008 an engineering study showed that the fatigue life of Hornet Centre Barrels could be extended beyond the current limits. As a result only 10 aircraft will require Centre Barrel Replacement. Additional discrete structural modifications are being undertaken on 42 aircraft to address fatigue damage, corrosion and other emergent ageing aircraft issues; 19 of these aircraft have been completed as at 30 June 2009.
As at 30 Jun 09, the first two prototype and one production centre barrel replacement aircraft have been returned to the fleet. The 4th - 6th aircraft have had the centre barrels replaced and are undergoing final rebuild at RAAF Base Williamtown. The 7th - 10th aircraft have had the centre barrel replaced and are undergoing initial rebuild in Canada, before being transported back to Williamtown for final rebuild and delivery.
The project remains within budget and schedule, with centre barrel replacement in full rate production. The program is scheduled to be completed by December 2012. All modified aircraft meet the project's technical specifications and have been accepted back into service.