Authorities greatly shrank that area after analyzing satellite data to determine Flight 370 had set off from Kuala Lumpur toward Beijing , turned around to go back over the Malay Peninsula , then ended up in the southern Indian Ocean . U.S. official : `` We need to maintain respectful optimism and be responsible '' Expert says refined search area manageable for underwater vessels . Possible discovery of plane 's pingers energizes search , but for how much longer ? Agency : Up to 15 planes are searching the ocean floor in a coordinated effort that could take months or years.
U.S. official : `` We need to maintain respectful optimism and be responsible '' Expert says refined search area manageable for underwater vessels . Possible discovery of plane 's pingers energizes search , but for how much longer ? Agency : Up to 15 planes are searching the ocean floor in a coordinated effort that could take months or years.