A previously unpublished transcript of an interview with Clark by German aviation journalist Andreas Spaeth, reveals the depth of doubt the industry veteran holds about nearly all aspects of the investigation into the disappearance of MH370. Emirates has more of the Boeing 777, the make of MH370, in its fleet than any other airline. Clark said his electronic engineers believe that even though the plane's Aircraft Communications Addressing and Reporting System, known as ACARS, was disabled it would still send out weak signals and remain traceable. To even disable the system, which allows the aircraft to communicate with the base through satellite, you would have to go through multiple steps including entering the avionics bay, he said. "That requires you to leave the flight deck and go down through a trap door in the floor to do that. But somehow this thing was disabled so much so that the ground tracking capability was eliminated."

Clark dismissed pilot suicide as a possible cause of the tragedy, saying the pilot would have ditched the plane in South China Sea rather than fly it for several more hours. "So if he was on a suicide mission, he would have done it then. Who then took control of the aircraft? Who then knew how to disable ACARS and turn the transponder off? That is a huge challenge." Clark also cast doubt bout the role of the Malaysian military, saying the claim that they identified MH370 as friendly when it suddenly reversed course and so took no further action was "bizarre" and needed to be "looked at very carefully". "I know this did not have to happen, there is technology to track these aircraft and everybody will say that, Boeing or Airbus," he said. "That is where the conundrum is of mystery, that is where we must be more forthright and candid as to what went on, it is not good enough for the Malaysian military to say: 'On a prime radar we identified it as friendly'.

"What would have happened if the aircraft would have turned back to fly into the Petronas Towers in Kuala Lumpur? But we identified it as as 'friendly'. Friendly with intent, or friendly without intent? But what was done? These are the questions that need to be asked of the people and the entities that were involved in all of this." An Australian-led search for the wreckage from the aircraft is currently underway in the southern Indian Ocean off the coast of Perth. Australian Transport Safety Bureau chief commissioner Martin Dolan said he was sure he had the all information he needed to find the plane and that he was "cautiously optimistic" of success. The bureau is co-ordinating the search and recovery of the debris but the Malaysian Government is responsible for the investigation itself. Fairfax Media sent questions to the office of the Prime Minister of Malaysia, Najib Razak, about intelligence-sharing and the tracing of MH370 on the military radar but was directed to comments he made in The Wall Street Journal in May. In the opinion piece, Mr Razak said Malaysia had overcome diplomatic and military sensitivities to bring 26 different countries together in the search.

He also said the aviation industry should consider changing aircraft communication systems so they can't be disabled mid-air. "Without physical evidence, or a clear explanation for why this happened, peoples' attention has naturally focused on the authorities - and Malaysia has borne the brunt of the criticism," Mr Razak wrote. "In the passage of time, I believe Malaysia will be credited for doing its best under near-impossible circumstances." A Malaysia Airlines spokeswoman also said the carrier could not comment on whether pilots were trained to disable ACARS or how many people on board the flight would have known how to stop the system, as the matter was "under investigation".