The US State Department has issued a list of updated approvals for equipment related to Singapore’s upgrade of its 60 Lockheed Martin F-16 Block 52 fighters.

The total value of the approved equipment comes to $130 million. It details requirements not contained in the Defence Security Cooperation Agency’s (DSCA) previous notification in January 2014, which valued the total upgrade at $2.4 billion, says the agency in a statement.

The revised approval covers a range of equipment, notably 50 Boeing joint helmet-mounted cueing systems (JHMCS), 90 BAE Systems AN/APX-126 advanced identification friend and foe (IFF) interrogator/transponders, and 92 Link-16 terminals.

The number of JHQC sets and IFF transponders vary from those listed in early 2014. The previous approval called for 70 JHMCS sets, which is 20 more than in the current document. The additional requirement also calls for 70 AN/APX-125 IFF transponders, but now Singapore appears to want 20 additional IFF units, and of a different standard - the AN/APX-126.

The revised document makes no mention of any changes to the main element of the upgrade, the addition of an active electronically scanned array (AESA) radar to the fleet. The January 2014 approval allowed for 70 AESA sets.

The issuance of the new approval suggests that work is underway between Washington D.C. and Singapore to move the upgrade programme forward.

Industry sources have indicated that Lockheed Martin will handle the avionics component of the upgrade programme, and Northrop Grumman will supply its Scalable Agile Beam Radar for the radar component.