At that time, the captain was outside the cockpit, Christine Negroni said in her new book, “The Crash Detectives”.

“The captain probably left the cockpit, leaving the first officer in command of the aircraft,” she said.

By some mechanism that she can’t explain, there was a sudden and rapid decompression of the aircraft, “causing the first officer to respond appropriately”.

The terrifying situation that followed triggered hypoxia, said Negroni. “Humans, when starved of oxygen, become disoriented and behave as if drunk.”

She does not think the passengers would have suffered. The first officer, the only technical crewman in the cockpit, may not have donned his oxygen mask fast enough. “He could not make rational decisions.”

The author, exploring why the first officer did not put on his oxygen mask fast enough, thinks that he may have been on the transponder.

Instead of donning the oxygen mask first, he was dialling 7700, the emergency code, to alert everyone that he was having an emergency.

“Instead of turning on the transponder, he may have inadvertently put it on standby, and that would have severed the connection,” said Negroni.

“Otherwise, those on the ground would have known it was MH370.”

The author also explains why the first officer did not land in Penang and instead headed towards Langkawi.

“I don’t know why. He trained in Langkawi,” she said. “He may be familiar with Langkawi.

“Also, with a heavier plane, he may have thought that he needed a longer runway as in Langkawi.”

The catch in this theory is that MH370 didn’t land in Langkawi.

The result of the fatal error was the ill-fated plane going on a ghostly journey from which there was no return.

Negroni asked Malaysia Airlines for a response on the last moments of the plane, and a detailed safety audit, but didn’t get any.

Elsewhere in the book, she charged that Malaysia Airlines knew a year before MH370, a Boeing 777-200, went missing that it would be difficult to contact in case there were problems.

Apparently, the company was given a detailed safety audit in 2013, a year before March 8, 2014 when MH370 went missing. The audit should have grounded all wide-bodied jets in the fleet, she claimed.

Negroni cautions against the black box explaining what happened to MH370.

The author said she was “fed up” of everyone saying that the world would not know what happened to MH370 unless the black box was found.

She wants the Australian Government to call on Malaysia to release complete and transparent records on the aircraft that flew as MH370.

For starters, the airline could not track the aircraft.

For another, the aircraft was not technically compliant to fly.

Again, there appears to have been issues with the servicing of the crew’s oxygen canisters.

“When was the last time the mask oxygen interface was inspected? Were the masks working properly?”

MH370 disappeared two years ago when flying from Kuala Lumpur to Beijing with 239 passengers and crew.

It is known the plane stopped just short of Vietnam before turning back and making its way across the north of the Malay peninsula.

Military radar tracked it over Pulau Perak in the Strait of Malacca and the northern tip of Sumatra.

It is believed the aircraft ended in the southern Indian Ocean, off Australia.

Watch the video below to learn more about Negroni’s theory:

Former WGN reporter, aviation journalist gives theory on disappearance of Malaysia Flight 370