A sophisticated US Navy surveillance plane supporting anti-terror operations in Afghanistan crashed into the Arabian Sea and one of four crew members is still missing, the US Fifth Fleet said on Wednesday.
The E-2C Hawkeye aircraft experienced mechanical malfunctions, forcing the crew to perform a "controlled bail-out," it said in a statement.
Three of the four crew were later recovered and a search is now under way for the fourth crew member.
An investigation has been launched into the incident. The crew was stationed on the USS Dwight D Eisenhower aircraft carrier.
The aircraft had crashed into the sea at about 1400 local time (1000 GMT) on Wednesday, the statement said.
It said the plane "was returning from conducting operations in support of Operation Enduring Freedom" in Afghanistan when the problem had occurred.
"Operation Enduring Freedom" is the name used by the US military for its war in Afghanistan.
The identities of the crew are being withheld pending notification of next-of-kin.
The E-2 Hawkeye is a twin engine and turboprop aircraft plane that can carry up to five crew members. It can provide all-weather airborne early warning, in addition to surface surveillance, combat coordination and search and rescue operations.