Questions remain unanswered despite huge search efforts

Crew members on board a US Navy P-8A Poseidon man their workstations while assisting in search operations for Malaysia Airlines flight MH370 over the Indian Ocean, in this handout photo taken March 16, 2014. Malaysia has appealed for help and international coordination in a search for its missing passenger jet that stretches across two corridors from the Caspian Sea to the southern Indian Ocean, diplomats said on Sunday.[Photo/Agencies]