Austria is to phase out its fleet of 15 Tranche 1 Eurofighter Typhoons from 2020, amid a deepening row with the four-nation consortium over the cost and capability of its aircraft.

Vienna in February began legal proceedings against Airbus Defence & Space and Eurofighter over alleged fraud and deception related to its near €2 billion ($2.28 billion) acquisition of the Typhoons in 2003. Airbus and the consortium deny the accusations.

But its proposed exit from Eurofighter operations from the end of the decade reveals the depth of Vienna’s dissatisfaction with the Typhoon.

The Austrian defence ministry describes the Tranche 1 Typhoons, which it received between 2005-2008, as possessing “limited equipment and significant cost uncertainty”.

It says retaining the 15-strong fleet for the next 30 years would see it incur costs of between €4.4 billion and €5.1 billion ($5 billion-$5.8 billion). Figures produced by a special commission appointed to examine the issue suggest the fleet switch would generate potential savings of €100 million to €2 billion in the period to 2049.

At present, Austria conducts airspace policing missions with the Typhoons, as well as an aged fleet of 17 Saab 105OEs. These, it says, will require replacement from 2020.

By aligning the out-of-service dates, Vienna will be able to move to a one-type fleet of 15 single- and three twin-seat aircraft, it says.

Defence minister Hans Peter Doskozil says: "Those who say yes to Austrian neutrality and sovereignty must also say yes to modern, high-performance supersonic aircraft capable of round-the-clock operations.

“At the same time, we need to get the escalating costs of the Eurofighter under control and minimise the enormous cost risks associated with it – in the interests of the taxpayer, and also in relation to the other branches of the armed forces.”

Austria has based its decision on a report generated by the special commission it set up in March, headed by the air force chief Brig Karl Gruber.

The report concludes that the air force requires a new fleet of supersonic fighters, able to operate round the clock, and equipped with guided missiles and an advanced self-defence system.

It says the new aircraft should be acquired via a government-to-government deal and could either be purchased or leased. A separate commission has now been established to examine aircraft and acquisition methods, says the defence ministry.

Among the 19 options analysed by the commission was the upgrading of its current Typhoon fleet and acquisition of three used two-seaters.

“However, continued operations with the existing Austrian Eurofighter fleet would involve cost risks that are difficult to quantify at present," says Gruber, noting the gradual replacement of Tranche 1 examples by the consortium's partner nations Germany, Italy, Spain and the UK.

"Consequently, it appears likely that there will be no uniform Eurofighter Typhoon Tranche 1 system in the future," he says.

Eurofighter declines to comment on the detail of the Austrian report, although it says: ‎"This is an Austrian defence procurement discussion and it is not for us to comment. However, the Eurofighter works very well for all other customers."

As the Saab 105OEs are also used for training missions, the report also signals Austria’s possible intention of replacing its fleet of Pilatus PC-7 turboprop trainers at the same time.

If the PC-7s are phased out it will look to buy training hours from a European partner in the short term, while in the longer term Vienna would upgrade its simulator training and purchase a “high-efficiency trainer” aircraft. It does not specify if this would be jet- or turboprop-powered.