Alleged hijackers on the MH370 could have flown along so-called flight information regions (FIRs) to avoid detection by the Thai and Malaysian militaries, RAF navigator Steve Pierson told Jeff Wise, author of the book "The Plane That Wasn't There". According to Pierson, after disappearing from the secondary radar near a waypoint called IGARI, MH370 flew along the borders of the Kuala Lumpur and Bangkok FIRs.
This trick could’ve made the air traffic controllers in each of the FIRs think that the other one would handle the plane, the RAF navigator explained. Civilian controllers normally check with each other to avoid confusion in such situations, he added, but since the plane only showed up on military radars, it remained unnoticed by both sides.
"That's quite clever. If you fly down the FIR boundary the controller on each side might assume the other was controlling you. They might think: 'Oh, that must be the other country's aircraft, that's not my problem, I won't worry about it.' And the other country thinks: 'Oh, that's their problem, I won't worry about it'", Pierson said.
The author of an investigative book about MH370, Jeff Wise noted that the alleged hijackers' plan had apparently worked and the plane's presence on military radars remained unnoticed until the records were brought up after the jet's disappearance. Pierson added that the individuals knew "exactly what they were doing" and alleged that they could have had a military background.
However, the official investigation, which lasted for several years after the plane's disappearance, has failed to reach any conclusion on the reason why MH370 changed its course and disappeared from radar screens in the region. The aircraft’s remains have still not been found, and multiple enthusiasts are pursuing different theories in a bid to locate where the plane crashed or landed, because some have suggested it was deliberately hijacked.
Malaysian Airlines flight MH370 disappeared on 8 March 2014 while carrying 239 people from Kuala Lumpur to Beijing. It disappeared from civilian radars at 17:21 UTC, but was spotted on military radars until 18:22.