SEOUL (Reuters) -GE Aerospace, whose joint venture made the engines of the Boeing airplane that crashed in the deadliest aviation disaster on South Korean soil, joined the investigation as Seoul extended by a week special inspections of all 101 Boeing 737-800 jets. The transport ministry extended to Jan.10 its inspections following the crash of a Boeing 737-800 operated by Jeju Air that killed 179 people, Joo Jong-wan, the deputy transport minister for civil aviation, told a press briefing.