Eight people were saved on Wednesday after their US Navy transport plane crashed in the Pacific. Three out of the eleven people on board remain unaccounted for, the Navy announced. The eight people who were rescued were recovered in good condition. “Search and rescue efforts for three personnel continue with US Navy and Japan Maritime Self-Defense Force (JMSDF) ships and aircraft on scene,” the US Seventh Fleet said in a news release. “The incident will be investigated.” The Navy said in a tweet that the eight survivors were brought aboard the USS Ronald Reagan. Their C-2 Greyhound transport aircraft crashed while on its way to the carrier about 150 kilometers (90 miles) northwest of Okinotorishima, a Japanese atoll. The Navy said the ship was operating in the Philippine Sea, which is east of the Philippines, when the crash occurred at 2:45 pm Japan time. The names of the crew and passengers are being withheld pending next of kin notification. The cause of the crash was not immediately clear, the Navy said. The plane was taking part in an ongoing joint US-Japan naval exercise in waters surrounding Okinawa from November 16-26. The Navy called it the "premier training event" between the two navies, designed to increase defensive readiness and inter-operability in air and sea operations. Japanese Minister of Defense Itsunori Onodera told reporters the US Navy had informed him that the crash may have been a result of engine trouble. The propeller powered transport plane carries personnel, mail and other cargo from mainland bases to carriers operating at sea. C-2 aircraft have been in operation for more than five decades and are due to be replaced by the long-range tilt-rotor Osprey aircraft. The 7th Fleet has had two fatal accidents in Asian waters this year, leaving 17 sailors dead and prompting the removal of eight top Navy officers from their posts, including the 7th Fleet commander. The USS John S. McCain and an oil tanker collided near Singapore in August, leaving 10 US sailors dead. Seven sailors died in June when the USS Fitzgerald and a container ship collided off Japan. The Navy has concluded that the collisions were avoidable and resulted from widespread failures by the crews and commanders, who did not quickly recognize and respond to unfolding emergencies. A Navy report recommended numerous changes to address the problems, ranging from improved training to increasing sleep and stress management for sailors.