Another promising lead in the search for flight MH370 has been dashed. Vietnamese officials say their search planes have failed to find any signs of what was thought to be floating debris spotted by a Chinese satellite.

Almost a week after Malaysia Airline Flight MH370 went missing, the search continues. On Thursday, Vietnam launched an all-out air search over the South China Sea.

"This, after China released a satellite image of what appeared to be objects floating on waters between Vietnam and Malaysia, somewhere near the plane's flight path. We were on board one of the search planes, and for nearly three hours, we kept our eyes open for any sign of the missing aircraft."

"We are now flying over the South China Sea, just off the southeastern coast of Vietnam. And we are flying about 6,000 feet above sea level. Now we've been told that at this moment, there are other aircrafts circling the area, including another one of Vietnam's and one from Singapore. A dozen countries have joined the search for the missing Malaysian airliner, but it remains a daunting task as the search area now covers some 27,000 square nautical miles." said Barnaby Lo, Vietnam.

The satellite image had offered some hope that at the very least, the search area could be narrowed down. But none of the search planes - including the one we were on - had found anything.

Instead, it keeps expanding, to the west, all the way to the Andaman Sea, further east in the South China Sea, and even, on land.

Despite this, Vietnamese officials say they will continue searching.

"We will not stop even if we have to hold on to just a single shred of hope." said Hoang Thanh Phong, Vietnamese Air Force.

Hope that is slowly fading away as each day brings more questions than answers.