A €40 million contract to buy eight new aircraft for the Air Corps is due to be completed next week.
Despite Government cutbacks across all Departments, the contracts to buy eight training aircraft at a cost of €5 million each are to be signed with the Swiss company, Pilatus, next Thursday.
A spokesman for the Department of Defence said he could not comment until the contracts were signed.
The PC-9M advanced turbo trainer aircraft will be primarily used for training Air Corps pilots. They may also be used in a security role, for example to patrol airspace during high-profile events such as visits by heads of state.
With a top speed about 200 miles an hour slower than a jumbo jet, they are not seen as having significant anti-terrorist capabilities. However, pilots will be trained to deploy weapons such as rockets and cannon.
The pilots will be trained in the military air base in Baldonnel, Co Dublin. Each pilot is expected to complete training in about 18 months.
Pilatus is a major aircraft manufacturer based in Stans, near Lucerne. It has already sold more than 230 PC-9Ms to 12 military customers around the world.
The new aircraft will replace the Marchetti aircraft, bought by the Air Corps in the 1970s.
Pilatus beat a US company Raytheon and a Brazilian company Embraer to win the Irish contract. Air Corps and Department of Defence staff travelled abroad to visit their factories during the assessment process.
The new aircraft are expected to be delivered to Dublin in about 15 to 18 months.
When the Minister for Defence, Mr Smith, announced the short-list for the contract last October, he said the purchase was "part of the ongoing commitment of the Government to the modernisation of the Permanent Defence Force".
There would be "unprecedented investment in new equipment and infrastructure in the Defence Forces" up to 2010 and he said 40 armoured personnel carriers (APCs) would be included in the shopping list of equipment.
However, last week The Irish Times reported that government cutbacks had forced the Department to curb its plans for 40 APCs.
Mr Smith signed a contract with the Swiss company Mowag in December to buy just 25 of the internationally-regarded Piranha 8x8s, spreading the €33.2 million cost over three years.
When Mr Smith announced the tender for the trainer aircraft, he said the project was a vote of confidence in the future of the Air Corps. It would allow the corps to continue to train pilots to the highest standards and would help to attract young cadets into the service.
In the past, the Department of Defence had found it difficult to retain pilots in the Air Corps as the private sector lured them away with lucrative job offers.
In 1997, the Defence Forces offered an unprecedented £10,000 pay rise to about 30 pilots to halt the haemorrhage of experienced pilots.
The then minister for defence, Mr Andrews, said there was a danger that the Air Corps could become a training school for commercial airlines.
