KUALA LUMPUR, March 20 — Where many suspect a nefarious plot in the erratic flight path of the missing Malaysia Airlines plane, a former US transport chief believes the pilots may have been battling to save all 239 people onboard MH370.

Mary Schiavo, a CNN aviation analyst and former inspector-general for the US Department of Transportation, has resisted suggestions of pilot collusion behind the unexplained jetliner's disappearance even as investigations deepen into the personal lives of its two cockpit crew members.

"I've worked on many cases were the pilots were suspect, and it turned out to be a mechanical and horrible problem," she was quoted saying by US broadcaster CNN in a report on its website posted last night.

Schiavo was also reported saying she was not surprised investigators had found nothing suspicious in the homes of the two Malaysia Airlines (MAS) pilots to shed further light on the vanished plane.

"And I have a saying myself: Sometimes an erratic flight path is heroism, not terrorism. And I always remind myself of that, not to jump to that conclusion. Sometimes pilots are fighting amazing battles, and we never hear about it," she was quoted saying.

New information disclosed by Thai authorities yesterday show the Beijing-bound plane had turned back and swerved sharply westwards 12 minutes before MH370's co-pilot, Fariq Ab Hamid, radioed Malaysian air traffic controllers with the last words, "All right, good night".

The CNN report noted that analysts had widely varying takes on its the significance of the timeframe lag, with some like New York Times reporter Michael Schmidt saying the new information "makes the issue of foul play seem more significant."

"what it basically shows is that this thing was already heading in a different direction when they're saying good night," Schmidt was quoted saying.

Experts have been poring over every minute detail and offering various interpretations on every aspect of the Boeing 777-2000 flight, its passengers and crew since the jumbo jet blipped off satellite radars at 8.11am on March 8.

Officials have said someone with in-depth and professional knowledge of flying had changed the plane's flight path that had been programmed for Beijing, however, the identity remains unknown.

Investigators have redoubled efforts to recover deleted data from MH370 pilot, Captain Zaharie Ahmad Shah's home-made flight simulator, spurring speculation of sabotage.

But acting Transport Minister Datuk Seri Hishammuddin Hussein has made it clear that all the passengers and crew onboard should not be presumed guilty until there is strong evidence to back the rumours.

“The passengers, the pilots and the crew remain innocent until proven otherwise,” Hishammuddin told a news conference in Sepang yesterday.

“For the sake of their families, I ask that we refrain from any unnecessary speculation that might make an already difficult time even harder,” he added.