The F-35 Lightning II aircraft fleet surpassed 16,000 cumulative flight hours through 30 April 2014. Test pilots at three locations flew a monthly record high 282 flight hours and 153 flights in April. In April, operational F-35s fleet-wide flew 812 hours. Cumulative totals for 2014 include 420 hours on F-35A test aircraft, 281 hours on F-35B test aircraft, and 222 hours on F-35C test jets. Operational F-35 pilots in all three variants have flown 2,790 hours for the year. Block 2B software flight science testing on the F-35A fleet is now nearly complete, and Block 3 software testing is expected to begin in mid 2014. Block 2B testing for the F-35B is expected to be completed later this year.