The first F-35B, with the short takeoff/vertical landing capability, is due to fly in May or June, Dan Crowley, Lockheed Martin F-35 vice president and general manager, told reporters during a teleconference April 8. There are ongoing issues with the lift fan, however, which the F-35 program executive officer, Air Force Maj. Gen. C.R. Davis, said are well understood and are being fixed. The STOVL version has been hitting all its milestones for 16 months and should be able to fly in the hover mode, as scheduled, in the fourth quarter of this year, Crowley said. The aircraft will fly and be shaken out first in conventional take off and landing mode, working up gradually to hover tests, he said.