NORFOLK, Va. – Navy investigators have been unable to determine what caused a twin-engine radar plane to crash off North Carolina’s coast last August, killing three aviators.

A report released Monday indicates the E2-C Hawkeye experienced problems with a cockpit indicator during flight the preceding day. It also notes the most recent maintenance records were onboard when the plane crashed.

Thirty-year-old Lieutenant Cameron Hall of Natchitoches, La.; 31-year-old Lieutenant Ryan Betton of Collinsville, Va.; and 25-year-old Lieutenant Junior Grade Jerry Smith of Greenville, Maine, died in the crash.

The plane went down just after takeoff from the Norfolk-based aircraft carrier USS Harry S. Truman during exercises that involve taking off and landing on a carrier deck.