Airliners are not built to fly in the way that whoever was piloting MH370 apparently flew it after breaking contact with the ground.

As the search for the missing flight MH370 enters its 10th day with few clues as to its whereabouts, the New Straits Times said today the Boeing 777-200ER dropped 5,000 feet (1,500m) to evade commercial radar detection.

In an exclusive story, the government-backed paper said investigators analysing MH370’s flight data revealed that the 200-tonne, fully laden twinjet descended 1,500m or even lower to evade commercial (secondary) radar coverage after it turned back from its flight path en route to Beijing.

The Malaysia Airlines Boeing 777-200ER (9M-MRO) disappeared on March 8 with 239 people on board. Malaysian authorities said on Saturday the plane was deliberately diverted and its on-board transmission devices switched off to avoid detection.

Its last contact was at 8.11am north of the Strait of Malacca.

Investigators poring over MH370’s flight data had said the plane had flown low and used “terrain masking” as it flew over the Bay of Bengal and headed north towards land, the NST reported.

Officials, who formed the technical team, were looking into the possibility that whoever was piloting the jet at that time had taken advantage of the busy airways over the Bay of Bengal and stuck to a commercial route to avoid raising the suspicion of those manning primary (military) radars, the paper said.

“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 NST quoted an anonymous official as saying.

Depending on the terrain, flying low to evade radar can make for a very rough flight. Planes evading radar essentially hug the ground, going up and down over hills as needed to remain close to the terrain. Jet fighters do it well, while the C-130 I once flew in during a simulation drop run don’t take to it well at all. Ordinary turbulence can combine with the terrain-hugging to produce a nauseating experience. The 777′s passengers in this case probably had a rough run as long as they were over land.

The apparent fact that MH370 flew low to evade radar might hint that it didn’t actually go very far once it went off course. If there was a plan to steal the plane for some later purpose, it would have made sense to have it shut off communications, go off course, go low to evade radar and then once it passed Malaysian military radar and went fully off the grid, head for some nearby airstrip to save fuel for whatever the plane’s eventual purpose was. The seven hours that the plane was said to be in communications with satellites could either have been an oversight by the thieves, or a diversionary tactic to throw investigators off the trail.