KUALA LUMPUR, June 30 — Foreign aviation experts now have more evidence indicating that someone aboard missing Malaysia Airlines flight MH370 had tampered with the aircraft's systems before the plane went down four months ago.

According to The Telegraph, Australia's report last week on the aircraft's disappearance showed the Boeing 777 jetliner had suffered a mysterious power outage some 90 minutes into its flight on March 8, possibly because someone inside the cockpit was trying to minimise the use of the aircraft's many systems to avoid radar detection.

The report said that this was determined when the aircraft's satellite data unit made an unexpected "log on" request to Inmarsat's satellites, or a "handshake", which was likely caused by a power failure.

"A log-on request in the middle of a flight is not common," the report released by the Australian Transport Safety Bureau (ATSB) on Thursday observed, the UK daily reported.

"An analysis was performed which determined that the characteristics and timing of the logon requests were best matched as resulting from power interruption."

The latest observation again casts a spotlight on MH370's flight Captain Zaharie Ahmad Shah who, according to another report by The Telegraph last week, has become a prime suspect in the aircraft's mysterious disappearance on March 8.

But the report, which quoted unnamed sources close to air crash investigators, has since been rubbished by Malaysia's former acting transport minister Datuk Seri Hishammuddin Hussein.

Weighing in on ATSB's findings, Loughborough University aviation safety expert David Gleave agreed that the power supply interruption could have been caused by someone tinkering with the aircraft's systems.

Gleave was reported saying the pattern was consistent with someone attempting to shut down the plane's communications and other systems in order to skirt radar detection.

"A person could be messing around in the cockpit which would lead to a power interruption," he was quoted saying.

"It could be a deliberate act to switch off both engines for some time. By messing about within the cockpit you could switch off the power temporarily and switch it on again when you need the other systems to fly the aeroplane."

A recent report on MH370's disappearance showed the Boeing 777 jetliner had suffered a mysterious power outage some 90 minutes into its flight, The Telegraph reported. — Reuters pic

Gleave said it was possible that the power failure was caused by a mechanical malfunction aboard the plane but added that this would not have permitted the plane to fly thousands of miles further and into the southern Indian Ocean, where it is believed to have crashed.

Peter Marosszeky, another aviation expert, agreed with Gleave's observation that the power interruption had been a deliberate and "conscious" attempt by someone on board.

"It would have to be a deliberate act of turning power off on certain systems on the aeroplane.

"The aircraft has so many backup systems. Any form of power interruption is always backed up by another system," the expert from the University of New South Wales was quoted saying.

"The person doing it would have to know what they are doing. It would have to be a deliberate act to hijack or sabotage the aircraft."

The Telegraph also spoke to Inmarsat's Chris McLaughlin, who concurred with ATSB's findings on the power failure.

"It does appear there was a power failure on those two occasions. It is another little mystery. We cannot explain it. We don't know why. We just know it did it," the British satellite communications firm's senior vice president for external affairs.

According to the ATSB report, the widebody aircraft carrying 239 people tried to log on to Inmarsat's satellites at 2.25am, three minutes after Malaysia's military radar spotted it.

The Telegraph said this was when the plane had already veered off its intended flight path to Beijing and was flying north of Sumatra in Indonesia.

Six hours later, MH370, now far off course, issued another log on request, which the daily said is believed to have been caused by it running out of fuel over the southern Indian Ocean.

Between the first and final handshake with Inmarsat's satellites, there were five others but they had not been initiated by the plane and were not considered unusual, the daily wrote.

Apart from observations on the power failure on board MH370, the ATSB report also said the passengers and crew in the aircraft had likely died from suffocation and the plane had drifted on autopilot before it crashed.

Investigators have yet to pinpoint the location of MH370's final resting place, despite months of frantic searching by international teams.

The aircraft carrying 239 people disappeared mysteriously off Malaysia's coast on the early morning of March 8, barely an hour after it left the Kuala Lumpur International Airport for Beijing in China.