Malaysia Airlines MH370
A model during an art performance in support of the passengers of the missing Malaysia Airlines MH370 at the departure hall of the Kuala Lumpur International AirportReuters

Investigators searching for the missing Malaysia Airlines Flight MH370 are now turning their attention towards another possible theory, explaining the sudden disappearance of the flight from the civil radar system.

The newly explored theory points towards the possibility that whoever was in control of the plane when it veered off its course deliberately flew the jet closer to the ground, in order to avoid detection.

The so-called "terrain masking" could potentially explain why flight MH370 was apparently able to evade being detected, after reaching the area which was reported to have been the last point of contact.

The New Straits Times reported that shortly after the plane took off from Kuala Lumpur and then veered off course towards the west, the plane was flying at an altitude as low as 5,000 feet, during most of the eight hours it was missing from the radar. The plane managed to elude the radars of at least three countries. "The person who had control of the aircraft has solid knowledge of avionics and navigation and left a clean track," an official told the paper.

The terrain masking technique is a clever means to avoid active radar, by positioning the airplane in such a way that there is natural earth hiding the aircraft from the radio waves sent by the radar system. The technique is often said to be used by military pilots to stealthily fly towards their target, using the landscape to mask their approach from the radar microwaves.

Nearly 11 days after the Malaysian Airlines jet disappeared with its 239 passengers and crew, an international team of investigators probing the issue has not been able to come up with any tangible results. With so few solid leads, investigators are forced to consider an endless list of possibilities and theories, no matter how bizarre and fanciful each one might be.

Investigators are looking at a search area, spanning some two million square miles. Several countries that lie in the northern and southern corridors, where the last satellite communication from the plane was reportedly established, have said that their radars did not detect any signs of an unauthorized flight entering their airspace.

However, it has been reported that this is precisely the reason why the theory that the hijacker might have used the technique of terrain masking holds good.

Although India said that it would not have missed the plane if it had entered its airspace, its military was quoted by the media, admitting that there were a "few gaps" in the country's civil and military radar system. Meanwhile, Pakistan also said the plane never flew through its airspace. Similarly, Kazakhstan, which is hypothetically the farthest the flight could have reached, said it did not detect any unauthorized flight crossing its airspace on 8 March.