A good 'history' of F135 engine problems here:
F-35 Grounded After New F-135 Engine Problems By Johan Boeder (Source: JSFNieuws.nl; published February 22, 2013)
F-35 Grounded After New F-135 Engine Problems
There is an apparent factual error here
AFAIK:
"...
Some facts about what happened
It was a F-135 engine with 700 hours, of which 409 flight hours. The aircraft was the F-35A test aircraft AF-2. The half-inch
wide crack was found in a turbine blade of the low pressure turbine section...." Perhaps it is a DUTCH language thing but here is what was reported earlier:
Half-inch crack blamed for F-35 fighter jet grounding: sources - Yahoo! News : "...The
engine blade crack that prompted the U.S. military to ground all 51 F-35 fighter jets
was over half an inch long, according to three sources familiar with the matter..."
Jul 22, 2008 briefing by Pratt & Whitney on engine problems and fixes
http://www.defense-aerospace.com/dae...efing-2008.pdf (8Mb)