All testing of the United State's new, single engine F-35 has come to a halt.

The suspension of all test flights comes after the discovery of cracks in the blades in the engine of one of the test planes. The crack was discovered during an inspection of one of the aircraft at Edwards Air Force Base in California. The engine was shipped back to Connecticut to the manufacturer of the engine, Pratt Whitney. It arrived there on Sunday where engineering teams are presently assessing the issue.

The cessation of testing involves 64 jet aircraft in the Pentgon’s $396 billion program.

Although the discovery of the crack is a set-back for the military program, Department of Defense spokesman, George Little insists that there is no wider problems involved with the fighter. He also stated, “There is absolutely no backing away from our commitment to the F-35 program.”

The F-35 aircraft is set to replace the fighter jets presently in the United States jet fighter arsenal now. The Pentagon plans on buying 2,456 of the aircraft in the coming decades.

The F-35 program is the Pentagon’s most expensive weapons project ever. When initial cost estimates for each F-35 fighter was made in 2001, it was determined that each would cost $50.2 million. Costs per aircraft are now estimated at $304.15 million, with costs estimated at $618 million over the operational lifespan of each jet. This will bring total costs of the program over the fleet’s operational life at over $1.51 trillion.

Norway has come up with different, higher numbers for lifetime costs of the aircraft. Testifying before a Canadian Parliamentary Committee in 2011, Norway’s Rear Admiral Arne Roksund estimated that the cost of each of their 52 fighter jets will exceed $769 million.

Japan has warned that if costs increase much more, they will have to halt their purchase of the new aircraft. Canada is saying that they are no longer fully committed to purchasing aircraft allotted to their defense program.

On top of ever-increasing costs, the F-35 has a multitude of problems that were identified in 2011, and in 2013, continued concerns of fuel tank and fueldraulics systems still remain vulnerable. Also, there are continued concerns with the sluggish acceleration and turning ability of the new aircraft.