The 71 fighter jets, brought into service in the mid-1980s, may need to keep flying beyond 2020 because of delays in acquiring the new Joint Strike Fighter, the Australian National Audit Office said yesterday.
It warned to expect a big increase in annual maintenance costs of the old Hornet fleet from $118 million since 2001 to $170m today, with costs expected to blow out to $214m a year by 2018. The report found all but nine of the Hornet fleet had "experienced structure fatigue above that expected for the airframe hours".
The ANAO's upkeep concerns are directed at the "classic" Hornets and not the newer fleet of 24 F/A-18F Super Hornets delivered to RAAF Amberley between 2010 and last year.
"The key risks to the F/A-18 fleets' fulfilment of their operational requirements until their replacement by the F-35A Lightning (JSF) revolve around Defence's ability to maintain the present levels of Hornet sustainment and structural-integrity management," the report said.
Keeping the old Hornet fleet flying beyond 2020 would incur an extensive increase in sustainment costs, ANAO said.
It "may well require the fleet to undergo an expanded, and hence more costly, safety-by-inspection regime, structural modifications program and capability upgrades".
The government has indicated it will buy 100 new Lockheed Martin-built F-35 Joint Strike Fighters, to replace the Hornet fleet in a deal worth $13.2 billion.
So far, it has committed to buy only two JSFs and in May announced plans to defer for two years the next acquisition of 12 of the stealthy, multi-role strike aircraft.
The audit report noted problems with the JSF program, including that it was progressing "more slowly and at greater cost than first estimated".
"At the time of the audit, almost 80 per cent of the F-35 test and evaluation program was yet to be completed, so significant F-35 key performance parameters had not been fully validated," the report warned.
Latest 2012 price estimates for individual JSF war planes were $US131.4m ($126.2m), projected to fall slightly next year and reach $US83.4m in 2019 when aircraft production is scheduled to increase.
RAAF's first two JSFs are scheduled for delivery in 2014 and will remain in the US for flight tests and evaluation.
Australia is one of nine partner nations involved in the JSF program, which has delivered more than $300m in contracts to Australian aerospace suppliers.
To bridge a looming capability gap following the retirement of the 1970s vintage F-111 fighter-bombers, the Howard government ordered 24 F/A-18F Super Hornets -- themselves due to be replaced by the F-35 (JSF) Lightnings by 2025.
On a plus note, the ANAO said recent initiatives to improve performance of the JSF program "are starting to show results".