Malaysian authorities are probing new information that the missing plane with 239 people on board dropped to an altitude of 5,000 feet or possibly lower to evade radar detection after it turned back midair.
Investigators are poring over the Boeing 777 flight MH370 profile to determine if it had flown low and used "terrain masking" during most of the eight hours it was missing from the radar coverage of possibly at least three countries, the New Straits Times reported today.
The officials are looking at the possibility whether the plane -with 239 people on board including five Indians and one Indian-Canadian - had taken advantage of the busy airways over the Bay of Bengal and avoided suspicion of military radars.
"The person who had control over the aircraft has a solid knowledge of avionics and navigation, and left a clean track.
It passed low over Kelantan, that was true," the paper quoted officials as saying.
The plane "would appear to be just another commercial aircraft on its way to its destination," it said.
"It's possible that the aircraft had hugged the terrain in some areas, that are mountainous to avoid radar detection." This technique is called terrain masking and is used by military pilots to fly to their targets stealthily, using the topography to mask their approach from prying microwaves.
The officials said this type of flying is considered very dangerous, especially in low-light conditions and spatial disorientation, and airsickness could easily set in.
"While the ongoing search is divided into two massive areas, the data that the investigating team is collating is leading us more towards the north," sources said.
Prime Minister Najib Razak last week said authorities are trying to trace the plane across two possible corridors - in the north to the border of Kazakhstan and Turkmenistan, and a southern corridor from Indonesia to the southern Indian Ocean.
Officials involved in the multi-national investigation said the probe would also focus on regions with disused airports equipped with long runways.
"There are two likely possibilities - either the plane landed somewhere and the engine was shut down or it crashed." "As soon as the first country comes up with evidence of the flight's position after its last confirmed position (320km northwest of Penang), we will be able to refine the search and better determine its possible location," the officials said.
The mystery of the missing plane from Kuala Lumpur to Beijing since March 8 continued to baffle aviation and security authorities who have not succeeded in tracking the aircraft despite deploying hi-tech radar and other gadgets.
Malaysian police have refocused the probe on the crew, passengers and ground staff based on "new leads" that the plane was deliberately disabled and its transponder switched off before the plane veered from its path.
Authorities examined a flight simulator found at the home of Captain Zaharie Ahmad Shah, the pilot of the missing plane, but initial forensics checks showed it was "clean", the paper said.
However, experts are probing deeper into the footprint of the homemade simulator.
Investigators are also probing a flight engineer who was among the passengers on the missing plane.
A Malaysian opposition leader and a close friend of Zaharie has said the pilot would have had the safety of his passengers uppermost in his mind, adding if there was foul play like hijacking then his friend would have been a victim.
Peter Chong, an aide to MP R Sivarasa of opposition PKR party, was reacting to a report in a British paper which termed Zaharie as a "political fanatic".
"Zaharie is someone who is very passionate about flying and very aware of the great responsibility a pilot bears towards his passengers and crew," Chong said.
"He is a management pilot, which means he doesn't just fly but is involved in training and examining other pilots." Zaharie, 53, began flying with MAS in 1981 and has more than 18,000 flying hours under his belt.
Meanwhile, the number of countries involved in the search and rescue operation has increased from 14 to 25.
Australian Prime Minister Tony Abbott today said his country will lead a search of the remote southern Indian Ocean for the missing plane.
Asked if Australian agencies had any data to back up the theory of mising plane's presence in the southern Indian Ocean, Abbott said he didn't have any information.
"But all of our agencies that could possibly help in this area are scouring their data to see if there's anything that they can add to the understanding of this mystery," he said.
Australia had two AP-3C Orion surveillance planes assisting with the search, now in its second week.
"One of our Orions as I understand it has been redeployed to the Indian Ocean search," Abbott said.
"We've got two Orions which have been assisting with the search. They remain available to assist in whatever way the Malaysian authorities wish and it's my intention to talk later today with the Malaysians to see if there's additional help that Australia can offer."
There were six Australians and two New Zealanders on the missing jet.