KUALA LUMPUR, March 10 — Human vision is the most effective tool in the ongoing search for missing Malaysia Airlines (MAS) flight MH370, an expert has said, in explaining the lack of success despite the array of advanced methods employed.

Speaking to aviation news website Flight Global, the airborne search and rescue specialist explained that the mysterious circumstances surrounding MH370 that vanished from radar shortly after departing for Beijing rendered many of the tools being used to find the aircraft ineffective.

“Radar is a wide area search tool... In this type of event, debris would typically be relatively small and floating low to the surface, making it very hard to ‘paint’ with the radar,” the expert told Flight Global, adding that matters were complicated by the fact that there is no Doppler speed differential between debris and the surrounding ocean for radar to detect.

Optical infrared scanners would also be of little use by now, he added, as the time elapsed would have caused any difference temperature that would have been exhibited by the aircraft and its contents with the water to dissipate.

Infrared operates on differences in temperature and is rendered “blind” if none exist.

The waters in which MH370 is believed to have gone down are also plied by a vast fleet of small fishing vessels that will cause false positives in the ongoing search, the specialist said.

Matters were exacerbated by the lack of a signal from the emergency transponders aboard the missing Boeing 777 or a distress signal from the plane that last made contact more than two days ago.

“The vague initial datum makes that area even larger, and time only expands it further,” he added.

Illustrating his explanation, search for the plane that initially covered a 20-nautical mile radius in the Gulf of Thailand has been widened to 50 nautical miles in the region and now includes the Straits of Malacca on the other side of peninsula Malaysia, according to the Department of Civil Aviation (DCA).

With hopes dimming as search efforts now stretches into its third day, authorities and MAS were today criticised by Chinese media over the handling of the plane’s disappearance.

Earlier today, DCA director-general Datuk Azharuddin Abdul Rahman insisted that Malaysian authorities acted correctly in handling the crisis, amid growing criticism that local response to the incident was not fast enough.

Flight MH370 has now been missing for more than two days since it lost contact after departing Kuala Lumpur International Airport for Beijing, China on March 8.

There were 239 people on board, including 12 crew members.