Rotor Blades on Navy Helicopter in Crash That Killed Five May Have Been Out of Balance

An MH-60S Seahawk that fell off the deck of the aircraft carrier USS Abraham Lincoln last month, killing five crew members, may have had rotor blades that were out of balance.

The San Diego Tribune reported on August 31 that the fatal crash off Southern California was caused by "side-to-side" vibrations, which caused the main rotor to hit the deck of the aircraft carrier when landing.

One crew member was rescued and five sailors on the carrier deck were injured. The crash summary provided in a Naval Safety Center document did not indicate what may have caused the vibrations to occur.

But Michael Canders, a retired U.S. military helicopter pilot and the director of the Aviation Center at Farmingdale State College in New York, told the Navy Times that the cause could have been unbalanced rotor blades.

"All of that has to be carefully balanced to make sure you don't have these sorts of excessive vibrations," he said.

The bodies of the five crew members who perished were recovered on September 5, according to The San Diego Tribune. Among them were two pilots, an aircrewman and two corpsmen who were attached to Helicopter Sea Combat Squadron 8, based at the Naval Air Station North Island.

"We are deeply saddened by the loss of five sailors and those injured following the MH-60S helicopter tragedy off the coast of Southern California. We stand alongside their families, loved ones, and shipmates who grieve," Chief of Naval Operations Admiral Mike Gilday said in a statement posted to Twitter.

The Navy said it performed more than 72 hours of coordinated efforts including 34 hours of search and rescue flights before pivoting to recovery. An investigation into the deadly accident is underway.

For more reporting from the Associated Press, see below.

MH-60S Seahawk helicopter crash USS Abraham Lincoln
Unbalanced rotor blades may have been at fault in the crash of an MH-60S Seahawk helicopter last month. Pictured an MH-60S Seahawk helicopter performing routine flight operation, Atlantic Ocean, July 4, 2018. Image courtesy Petty Officer 3rd Class Thomas Gooley / USS Harry S Truman. (Photo by Smith Collection/Gado/Getty Images)

The Navy announced on September 4 that the missing crewmembers had been declared dead and that the search efforts were shifting to recovery operations. The helicopter sank about 70 miles (112 kilometers) off San Diego.

The five sailors who died were identified as Lt. Bradley A. Foster, 29, a pilot from Oakhurst, California; Lt. Paul R. Fridley, 28, a pilot from Annandale, Virginia; Naval Air Crewman (Helicopter) 2nd Class James P. Buriak, 31, from Salem, Virginia; Hospital Corpsman 2nd Class Sarah F. Burns, 31, from Severna Park, Maryland, and Hospital Corpsman 3rd Class Bailey J. Tucker, 21, from St. Louis, Missouri.

The Union-Tribune reported Tuesday that the squadron's spouses club has raised almost $180,000 for the families of those who died.