The emergency shallow-water landing, which left the five Marines on board injured, was the result of the aircraft's rotor blades hitting a fuel line during nighttime aerial refueling, III Marine Expeditionary Force Commanding General Lt. Gen. Lawrence Nicholson has said.
Officials with III MEF announced that flights were resuming on Okinawa in a Dec. 18 news release. Nicholson notified the Okinawa Prefectural Government and Okinawa Defense Bureau before continuing flight operations, the release said.
"We have conducted a thorough, careful and exhaustive review of MV-22 aviation safety procedures and briefed Ministry of Defense and Ministry of Foreign Affairs officials," U.S. Forces Japan Commander Lt. Gen. Jerry P. Martinez said in a statement.
"While the investigation is ongoing, we are highly confident in our assessment that the cause of the mishap was due solely to the aircraft's rotor blades coming into contact with the refueling line," he added. "We greatly appreciate the strong support from our Alliance partner in the aftermath of this incident."
In Okinawa, where locals have long opposed the presence of the Osprey due to concerns about its safety record, some had hoped the Marines would pull the aircraft out of the region entirely in the wake of the crash.
On Dec. 15, the editorial board of the Okinawan newspaper Ryukyu Shimpo wrote a searing editorial calling on the Marines to leave Okinawa entirely and to cancel plans to build a new air station near Henoko Bay, Okinawa, to replace Marine Corps Air Station Futenma.
The editorial also accused the Marine Corps of minimizing the severity of the Dec. 13 crash by calling it a "shallow-water landing."
"As long as these dangerous and eerie-grey-colored aircrafts continue to fly, it would be no surprise if they eventually crashed somewhere. It has become all the more clear what needs to be done in order to protect the lives and dignity of Okinawans and to prevent casualties," the editorial board wrote.
In a statement, Nicholson said the decision to resume Osprey operations had been made after safety procedures were reviewed, and with the concerns of local Okinawans in mind.
"After a thorough and careful review of our safety procedures, checklists, and aircraft, I am highly confident that we can continue safe flight operations of the MV-22 in support of our Alliance partner and obligations," Nicholson said.
"It is very important for Japanese citizens to understand and share our utmost confidence in the safety and reliability of the MV-22, or we would not continue flight operations," he added. "It is equally important that we ensure our pilots have every opportunity to conduct training, which allows us to remain proficient, and enable us to respond when most needed in support of the Alliance."