U.S. Navy aviation mishaps involving the F/A-18 E/F Super Hornet have jumped 108 percent over the past five years, according to data obtained by Military Times.

From fiscal years 2013 to 2017 the number of Super Hornet accidents rose from 45 to 94 per year. Those numbers were predominantly driven by Class C mishaps, which occur when aircraft damage costs between $50,000 and $500,000 or there are lost work days due to injury.

And it’s not just Super Hornets. Across the Navy’s entire aviation fleet, mishaps jumped 82 percent — mostly Class Cs — during the past five years, the biggest spike in accidents among all four services, according to mishap data provided by the Defense Department.

The Navy is trying to understand why.

“As much as we dive into the data, it’s hard to pick the smoking gun, right?” said Capt. Dave Koss, force readiness officer for naval aviation. “So [Class] A and B mishaps remain relatively at statistical norms, but Class Cs have increased.”

The mishap data was obtained through multiple Freedom of Information requests to the Naval Safety Center.

The mishap narratives, one-liners that describe the incidents, do not reveal a common thread in the spike of Class Cs. Several Super Hornets were struck by lightning during carrier operations. There were engine fires, towing and flight deck collisions during taxi maneuvers, panels blown off aircraft by weather or the exhaust of other aircraft during shipboard operations, maintainer injuries and ground maintenance-generated damage, such as objects being closed within the Super Hornet’s canopy.