Don’t sound like they have too much confidence in finding survivors as nighttime would be the best conditions to see a flare or emergency strobe from the air.
I’d say you are probably right about that.
I do wonder if ASW radar is ever used in these situations, and if it’s at all effective. Figure if they can pinpoint a submarine periscope, they might be able to locate any intact large sections of a plane if it’s somehow still afloat.
From WSJAsia:
Vietnam Sends Ships to Investigate Oil Slicks
Vietnam is sending ships to the site of two possible oil slicks that could be from the jet engines of missing Malaysia Airlines flight MH370, a twin-engine Boeing 777 jetliner, the army’s deputy chief of staff said.
Search pilots spotted two possible oil slicks each 10 to 15 kilometers in length, about 500 meters apart, some 140 kilometers south of Tho Chu island off southern Vietnam, the government’s website said in a statement.
“We have sent vessels to the site of the suspected oil spills and they are expected to reach the site tonight. It’s very likely that this is the sign of the missing plane,” said Lt. Gen. Vo Van Tuan, deputy chief of staff of Vietnam People’s Army, speaking live on Vietnam national television.