By Geoff Fein

As a result of an emerging safety of flight issue with legacy Boeing [BA] F/A-18A-D Hornets, the Navy is grounding 104 of the aircraft after inspections revealed that cracking has occurred earlier than predicted in some airframes, according to the service.

To date, 13 Hornets have been inspected and six aircraft have had cracks, Marcia Hart-Wise, spokeswoman for the program executive office tactical aircraft programs, told Defense Daily Friday.

While repairs will be done at the depot level, when the repairs will begin and how long they will take, isn’t known yet, Hart-Wise added.

“If no cracks are found, the aircraft will be returned to full flight status with a recurring inspection every 100 flight hours,” she said. “If the magnetic field inspection is unavailable, a visual inspection will be performed. If no cracks are discovered, the aircraft will be returned to flight status with a 4G restriction and a recurring daily visual inspection.”

This issue was a known potential “high-stress focus area” and was assessed during the F/A-18A-D Service Life Assessment Program (SLAP), according to Lt. Nate Christensen, a Navy spokesman.

There are 635 F/A-18A-D aircraft in the Navy and Marine Corps. Currently, 104 F/A-18A-D aircraft exceed the test demonstrated life limit for this particular area of the aircraft and have the highest potential for cracks in this location, Christensen said.

“Of the 104 aircraft, 27 are in maintenance and 77 are in flight status. Of those 77, five are currently deployed to the U.S. 7th Fleet in Iwakuni, Japan, five are assigned to the Blue Angels, 44 are in fleet replacement squadrons and 23 are in fleet squadrons,” he said.

“At this time, there are no impacts to aircraft supporting operations in Iraq or Afghanistan,” Christensen added.

Preliminary investigation results indicate the Marine Corps F/A-18 mishap earlier this week in Beaufort, S.C., was not related or caused by this issue, Christensen noted.

Blue Angels aircraft participating in this week’s air show successfully passed the AFB-710 inspection March 11, with no crack indications and are cleared to fully participate, he said.