Here's some of the detail from a previous post, on the F-35's operational readiness.
Anyone know what the "FMC Rate" is/means?
I'm guessing perhaps fit for combat (probably marginally so), but haven't seen the acronym before.
14% doesn't sound good – see below.
Hope they brought spare tires, since the F-35Bs tires are rated for less than 10 landings, too.
"Below is the OTE chart showing F-35 availability.
As the report notes, "the F-35A FMC rate of 34 percent was significantly higher than other variants, with the F-35B at 14 percent and the F-35C at 15 percent".
"The average monthly utilization rate measures flight hours per aircraft per month. The utilization rate was 16.5 flight hours, reflecting the stable but low availability rate. The F-35A fleet averaged 18.0 flight hours, while the F-35B and F-35C fleets averaged 14.1 and 15.1, respectively."
F-35 AVAILABILITY FOR 12-MONTH PERIOD ENDING SEPTEMBER 2017 (sorry, you'll have to go to the link, since the tabular format doesn't copy well here – scroll down to see the variant breakdowns by unit):
link
Suffice it to say, for the F-35B, it varies between 35% – 60%, with an average of about 45% – 50%, or so.