At least 30 American troops have died in a spate of US military helicopter and tiltrotor aircraft crashes this year

• A US Air Force Osprey crashed off the coast of Japan on November 29, killing all eight Airmen aboard.
• It's the latest in a string of helicopter and tiltrotor crashes this year.

It's been a deadly year for US military helicopters and tiltrotor aircraft. Seven crashes around the world have so far killed at least 30 American service members and injured over 40 more.

None of these incidents occurred during combat or were the result of enemy fire; almost all took place during some sort of training mission. Two branches of the military grounded flights in response to crashes and the resulting loss of life.

Here's a timeline of these crashes and what we know about their causes:

February 15: UH-60 Blackhawk crashed in Alabama

A Tennessee National Guard helicopter crashed during a training flight near Huntsville, killing the two pilots. According to a statement from the Tennessee Department of Military, the aircraft was approaching a local airport when it "rapidly descended and impacted the ground."

March 29: HH-60 Black Hawks collide in Kentucky

Two US Army helicopters crashed into each other during a training "accident" near Fort Campbell, the 101st Airborne Division said, killing all nine soldiers who were on board. The aircraft were conducing a routine mission and were operating in "multi-ship formation" using night-vision goggles. They crashed into an open field across from a residential area.

April 27: AH-64 Apaches collide in Alaska

Two helicopters returning from a training mission crashed into each other near Healy, killing three soldiers and injuring a fourth, the 11th Airborne Division said. After this incident, the US Army temporarily grounded all aircraft except those participating in "critical missions."

June 11: MH-47 Chinook crashed in Syria

A US military helicopter with a faulty rotor crashed as it was landing at a staging base in the northeast, injuring 22 soldiers. A Pentagon spokesperson said at the time that the incident was under investigation, but all troops involved — including some who had to be evacuated to facilities outside the US Central Command's area of responsibility in the Middle East — were in stable condition.

August 27: MV-22B Osprey crashed in Australia

A US Marine Corps Osprey crashed on Melville Island during a training exercise, killing three soldiers and injuring another 20. Marine Rotational Force — Darwin said at the time that the cause was under investigation. This incident marked the second in a string of three "aviation mishaps" during August and September that eventually led the Marines to pause all flights for several days.

November 10: MH-60 Blackhawk crashed in the eastern Mediterranean Sea

Five US Army Special Operations aviation soldiers were killed after their helicopter experienced an "in-flight emergency" during aerial refueling training and crashed into the water, the Pentagon said. It added that there were "no indications" the crash was the result of hostile actions, amid soaring regional tensions as a result of the Israel-Hamas war.

November 29: CV-22B Osprey crashed off the coast of Japan

A US Air Force Osprey was involved in an unknown "aircraft mishap" during a routine training mission off the coast of Yakushima Island, killing all eight crew members aboard. Air Force Special Operations Command said on December 5 that a search and recovery mission was still underway to locate the remains of two Airmen.