GAO awaiting updated F-35 Block 4 plan

The Government Accountability Office said in an Aug. 8 report it remains concerned about the impact of concurrency on the F-35 Follow-on modernization effort, but is withholding recommendations until the Defense Department submits a report detailing its baseline plan for Block 4 development.

The DOD F-35 Block 4 report -- which Congress mandated in the Fiscal Year 2017 National Defense Authorization Act -- was due in March, but the department has told congressional defense committees it now expects to submit its plan this month.

The F-35 joint program office has stated it plans to take an incremental approach to Block 4 development. In April, the Joint Requirements Oversight Council approved the first two increments, Blocks 4.1 and 4.2, and the program will return for validation of future increments.

GAO's Aug. 8 report states that while the program appears to be implementing an approach that will allow for "informed management and oversight," officials have said they are reassessing Block 4 cost, schedule and capability due to budget uncertainty and changes in program leadership. This reassessment delayed the release of a request for proposals to late 2017 and pushed the baseline report from March to August.

One area of concern for GAO is concurrency between Block 4 development and Block 4 aircraft procurement. The service plans to request funding in the fiscal year 2019 budget request for the first Block 4 aircraft -- two years before development and test of that jet will be complete. Known development risks and uncertainties mean that the department "may be negotiating prices for those aircraft without knowing if or when the more advanced capabilities will be delivered and whether they will function as required," GAO states.

The department said its forthcoming report would address those concurrency concerns, according to GAO.

"We are not making any recommendations at this time because program officials told us that the concurrency issue is being considered as part of their reassessment of Block 4," GAO states. "We will therefore reassess this issue when DOD's F-35 Block 4 baseline report is issued and brief the congressional defense committees on our findings."