The issue is not expected to affect flying operations for any of the three variants, nor will it alter the US Navy's (USN's) ability to meet its planned Initial Operating Capability (IOC) for the C-model in August 2018, according to the JPO. The cost of the retrofits is not yet known.
The F-35C durability test article had already accumulated more than 13,700 test hours, which equates to 6,850 flight hours or more than 20 years of operational flying, according to DellaVedova. "All current F-35Cs flying today have less than 250 flight hours," he added
The F-35C variant is distinguished by its larger wings and more robust landing gear, designed for catapult launches and arrestments aboard naval aircraft carriers, and its wingtips fold to allow for easier storage aboard a carrier.
The F-35 program has experienced a number of cost overruns and developmental delays. The United States is projected to spend an estimated $323 billion for development and procurement on the program, making it the most expensive defense program ever.
In 2011, Rear Admiral Arne Røksund of Norway estimated that his country's 52 F-35 fighter jets will cost $769 million each over their operational lifetime. In 2012, the total life-cycle cost for the entire U.S. fleet was estimated at US$1.51 trillion over a 50-year life, or $618 million per plane. To reduce this high life-cycle cost over a 50-year lifetime, the USAF is considering reducing Lockheed Martin's role in Contractor Logistics Support
SOURCE - Janes, wikipedia