In November 2011, a Pentagon study team identified the following 13 areas of concern that remained to be addressed in the F-35:
The helmet-mounted display system does not work properly.
The fuel dump subsystem poses a fire hazard.
The Integrated Power Package is unreliable and difficult to service.
The F-35C's arresting hook does not work.
Classified "survivability issues", which have been speculated to be about stealth.
The wing buffet is worse than previously reported.
The airframe is unlikely to last through the required lifespan.
The flight test program has yet to explore the most challenging areas.
The software development is behind schedule.
The aircraft is in danger of going overweight or, for the F-35B, not properly balanced for VTOL operations.
There are multiple thermal management problems. The air conditioner fails to keep the pilot and controls cool enough, the roll posts on the F-35B overheat, and using the afterburner damages the aircraft.
The automated logistics information system is partially developed.
The lightning protection on the F-35 is uncertified, with areas of concern.
(πηγή wikipedia)
