As noted in the 2016 Director of Operational Test and Evaluation (DOT&E) report on the F-35, the GBU-12 has limited moving target capability. "However, Block 3i does not have an automated targeting function with lead-laser guidance (i.e. automatically computing and positioning the laser spot proportionately in front of the moving target to increase the likelihood of hitting the target) to engage moving targets with the GBU-12, like most legacy aircraft have that currently fly close air support (CAS) missions". Interestingly, the DOT&E report said that this deficiency is not planned to be addressed in Block 3F, which appears to run counter to what has been said regarding the recent test at China Lake.
"Instead, F-35 pilots can only use basic rules-of-thumb when attempting to engage moving targets with the GBU-12, resulting in very limited effectiveness. Also, limitations with cockpit controls and displays have caused the pilots to primarily use two-ship 'buddy lasing' for GBU-12 employment, which is not always possible during extended CAS engagements when one of the aircraft has to leave to refuel on a tanker. To meet the Operational Requirements Document stipulation for engaging moving targets, the US Air Force (USAF) is considering integrating the Raytheon GBU-49 Enhanced Paveway II, a fielded weapon that has similar size, weight, and interfaces as the GBU-12, or a similar weapon that does not require lead-laser guidance, in Block 3F. Otherwise, the programme plans to develop and field lead-laser guidance in Block 4.2, which would be delivered in 2022, at the earliest. However, because of the similarities, the GBU-49 could be quickly integrated with Block 3F to provide a robust moving target capability for the F-35 much earlier," the report continued.
To this end, the USAF on 10 February issued a 'sources sought' notice for an interim 500 lb-class weapon with a moving target capability for the F-35. The notification called for information from the US industry only on a non-developmental precision-guided munition capable of being integrated onto the F-35A, ahead of an expected request for proposals.
As noted by the Air Combat Command's request for information, an initial 400 weapons are being sought of a total inventory of 1,200. The first contract is expected to be awarded in the third quarter of fiscal year 2017, with deliveries of the initial order to begin no later than six months after the contract date.
Possible contenders for the requirement include the Boeing GBU-54/B Laser JDAM based on the MK 82 or BLU-111 500 lb bombs; as well as the Lockheed Martin Paragon (previously named Dual Mode Plus) Paveway II LGB kit fitted to the MK 82 or BLU-111.