What does Lockheed Martin have to do to mark the end, or close out, the System Development and Demonstration phase of the F-35?

  • 1
    $\begingroup$ This is really a contracting question. LM has to satisfy the SDD exit criteria that's defined in their contract with the F-35 program office. $\endgroup$
    – Gerry
    Feb 23, 2018 at 13:51
  • 2
    $\begingroup$ The best indication of what remains to be done is given by the annual US DOT&E reports. The latest edition is here: dote.osd.mil/pub/reports/FY2017/pdf/dod/2017f35jsf.pdf I could summarise it to produce a swanky answer, but to be honest, that's quite an effort. $\endgroup$
    – Penguin
    Feb 25, 2018 at 10:21
  • $\begingroup$ Are you asking about the A, B, or C model F-35? $\endgroup$ Apr 24, 2018 at 13:47
  • $\begingroup$ I was under the assumption that the end of SDD would be a program event for all three simultaneously. Will each variant close out SDD separately? $\endgroup$
    – edt11x
    Apr 25, 2018 at 21:25

1 Answer 1


The clearest explanation I have found, comes from the Congressional Research Service (www.crs.gov), from RL30563.pdf:

The F-35 is currently in low-rate initial production, with 280 aircraft delivered as of April 2018. At least 250 of those were in U.S. service. Four to five aircraft are currently delivered each month, with the production rate scheduled to increase to 120 per year by 2019. In keeping with the acquisition plan that overlapped development and production (known as “concurrency”), the F-35 was also in system development and demonstration (SDD), with testing and software development ongoing, from October 2001 until April 11, 2018. The SDD phase will formally continue until the end of Initial Operational Test and Evaluation, when a “Milestone C” full-rate production decision will be made.

A copy of the full PDF is available here:


We know from other sources that Initial Operational Test and Evaluation (IOT&E), will formally begin later this year, 2018.


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