The helicopter crashed and caught fire during a test flight after repairs at the base in the port city of Pohang, on Tuesday, July 17, the ministry said in a statement.
“Five of the six crew members on board were killed and the remaining one has been taken to hospital due to injury,” it said.
The helicopter was a domestically made model known as the MUH-1 or Marineon, Yonhap news agency said.
The Republic of Korea Marine Corps received its first two MUH-1 helicopters in January. The amphibious support MUH-1, a variant of the KUH-1 Surion light utility helicopter, was developed by Korean Aerospace Industries as part of a KRW800 billion ($744 million) program announced in April 2013.