"Given the fuel leakage incidents occurred in succession, the minister directed the aviation director of the Regional Civil Aviation Bureau to open an investigation and find the causes of the two leaks as soon as possible, " the ministry said in a statement.

BBC: Boeing Dreamliner investigation ordered by Japan

The jet carried a student pilot in the front seat and an experienced instructor behind him, and the leakage of jet fuel was "one of the indications that there was a mechanical malfunction, " Navy Capt.

CNN: 'Oh my God!' Callers recount Navy jet crash