Without knowing who had access, investigators cannot be sure if there was an opportunity for such a saboteur to have tampered with it.
Dr Leivesley said: “We know from the Malaysian government reports there was maintenance activity in it in February, but in the immediate period before the plane took off we don’t have that history.
“We need to know who had access to the plane.
“Was there an opportunity for someone to get on with a USB stick or in other ways to initiate a cyberattack on the plane so it would never reach its destination?”
Other aviation experts in the documentary emphasised the importance of getting to the bottom of the MH370 mystery.
Not only is it very important for families to get closure on the tragedy, it is also important to stop such an occurrence ever happening again.
For example, if it was a technical error with the plane that was to blame, this could affect other planes and would need to be identified as soon as possible for future passengers’ safety and security.
Aviation journalist David Learmount told Channel 5: “Learning what the fate of MH370 was is very important, because those of us in the aviation industry don’t like not knowing what happened to an aeroplane.
“It might have been a human thing, it might have been a technical thing.
“But especially if it was a technical thing we want to know what it was.”
One family member spoke to the documentary, imploring the authorities to help loved ones get some answers.
She said: “It is about finding the truth of what happened and no secrecy, no hiding of information.”
The official investigation into MH370 has said the presumed location of the plane is at the bottom of the southern Indian Ocean.
However, two attempts to find a wreckage have been unsuccessful and some doubt the calculations used.