MELBOURNE, Australia — The Royal Thai Air Force has requested Cabinet approval for funds to upgrade four more Northrop Grumman F-5 Tiger II interceptors, adding to an earlier contract to upgrade 10 aircraft, the service said.

The Air Force also provided additional details of the upgrade, which includes new data links, multi-mode radars, new weapons and electronic warfare systems. The upgraded aircraft, known as the F-5T Super Tigris, will also incorporate structural improvements that the Air Force says will add approximately 15 years to its service life.

The upgrade to the four aircraft in this latest phase will cost $96.1 million, which will see the installation of the Link-T tactical data link, connecting the aircraft to the Air Force’s command-and-control network and improving the networking capability of the type.

A new multi-mode radar, which the service says will provide the Super Tigris with beyond-visual-range capability, will be fitted, which will also have a synthetic aperture mode for high-resolution ground mapping. The radar type was not disclosed, although it is believed to be Elta ELM-2032 from Israel. Leonardo had also previously offered its Grifo X-band multi-mode radar to Thailand.

Thailand’s F-5 interceptors were already using the Israeli Rafael Python-4 agile short-range air-to-air missile and Elbit DASH IV helmet-mounted sight, and will now also add the Rafael Litening 3 targeting pod and Skyshield electronic countermeasures pod to its inventory. The communications suite of the Super Tigris will also be replaced with the jam-resistant HAVE QUICK II frequency-hopping sets.

This latest request will constitute the second phase of Thailand’s Super Tigris upgrade program. Israel’s Elbit had  announced in October 2014 that it had secured an $85 million contract to perform an avionics upgrade to F-5s for an unnamed customer in Asia, although Thai sources have since confirmed that the country was the customer involved.

The Air Force’s Super Tigris jets are assigned to the 211 Squadron at Ubon in east Thailand. This upgrade will see the type flying until the 2030s, serving alongside Thailand's Saab JAS-39C/D Gripens and Lockheed Martin F-16A/B Fighting Falcons.

A senior Air Force officer previously told Defense News that Singapore has donated a number of its retired F-5s to Thailand for use as spares, with other sources putting the number of airframes at about 10.

Thailand’s Air Force is also currently upgrading 18 of its newer F-16s with new radars and other improvements that include the Joint Helmet Mounted Cueing System and the capability to fire the Diehl BGT IRIS-T air-to-air missile.