[fiftymegaton]

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.

[milagro]

If the oil slicks are from the engines, it seems the distance between them indicates the possibility that they were separated from the plane BEFORE it went into the water.

But that's just my idea, based on pure speculation.