Even now, many months after the horrific disappearance, speculation still runs rampant as to what happened to Malaysian Airlines flight MH370.

Several weeks ago, a newspaper article on the search for MH370 stated that the search area — based on new information — had moved further south and that it was likely someone on board had tampered with the flight computers.

The article also stated that it was possible the aircraft flew for over seven hours on autopilot then ran out of fuel and crashed.

But after an aircraft crashes, masses of debris would be floating around for a long time afterwards. None has been found.

I was a senior captain with a major international airline flying a B777, the type of plane that has now vanished as flight number MH370.

I am bemused by the media coverage given to self proclaimed experts — people who have never flown a modern fly-by-wire computerised glass cockpit airliner and yet offer speculation as to what happened to MH370.

So the uninformed can join the dots and draw their own conclusions but I will point out what most probably did not happen.

media_camera Flashback: MH370 search vessel Go Phoenix in Fremantle, about to continue the serch for missing Malaysian Airline plane

The B777 has 80 computers and, except for two engines, nearly every system on board is triplicated to ensure a practically fail safe operation, for example three radios, three radar transponders (linked to Air Traffic Control), three autopilots, three flight management computers (FMS) etc etc.

Failures

And a failure of one will result in transfer, usually automatically, to another. This means for ATC to lose secondary radar contact with MH370 someone had to deactivate all three by manually selecting them to off.

A total electrical failure has also been speculated.The B777 has five generators (two per engine plus APU) and, as a final backup, an automatic deployment Ram Air Turbine ( RAT ) which can supply hydraulic and electrical power to vital systems and still have contact with ATC.

Then there is the hijack theory. On board were two pilots and 14 cabin crew. None of the passengers came under suspicion and the Flight Deck door is reinforced and kept locked. Airlines have security protocols in place to prevent unauthorized access to the Flight Deck.

media_camera A briefing aboard the survey ship Go Phoenix searching for MH370

The flight profile is programmed into the FMS computers before engine start and, with the autopilot(s) engaged, normally immediately after takeoff, the aircraft would have flown itself automatically to its destination unless there was human input to change the flight profile.

There are two lateral modes of flight, Navigation (NAV) and Heading (HDG), the latter normally only used if radar vectors are given by destination ATC to facilitate the instrument approach if required.

The flight crew could leave the Flight Deck after takeoff with the A/P engaged and the aircraft would take itself to the destination — it could not meander around the sky, not when under A/P control.

I might mention that it is not easy to fly a large airliner manually at altitude as they are not designed for it and B777 and Airbus Standard Operating Procedures ( SOP ) call for autopilot engagement at 400 feet after takeoff.

Explsive theories

There is also the explosive decompression theory. Practised regularly by Flight Crew in six-monthly B777 Simulator checks, all the emergency and abnormal scenarios are covered at some stage. Malaysian Airlines has a good reputation with well-trained crew that are proficient at Boeing Memory Emergency Procedures, which includes rapid donning of oxygen masks and selecting immediately the transponder to immiediatel notify ATC and then for rapid descent to a lower level.

The time of useful consciousness at 35,000 feet is 30 seconds — ample time for a well-trained crew to get the aircraft safely down to a lower altitude.

What about fire and smoke in the Flight Deck? Again Boeing has emergency procedures to cover this contingency and the crew would still have contacted ATC.

A bomb on board just doesn’t fit. It’s highly unlikely that the aircraft could then keep flying for several hours as has proved to be the case.

Subsequently, analysis of Malaysian military radar (the event happened in the early morning hours) suggests the aircraft tracked across northern Malaysia then deviated to the northwest before turning south to the southern Indian Ocean.

Is it a coincidence that this track managed to avoid Indonesian, Thai and then Indian military radar?

This analysis also suggested the aircraft climbed to 45,000 for 10 minutes. As a former RAAF fighter pilot who has experienced Hypoxia in high altitude training, it is known that over 35,000 feet, even breathing 100% oxygen, Hyposix can still occur due to the skin tension of lung alveoli (partial pressures) unless oxygen is fed to the mask. Only the Flight Crew masks have this capability.

media_camera Go Phoenix has been a core compnent in the search for MH370

Passenger drop down masks are designed to provide chemically generated oxygen for 10 minutes to enable the crew to get the aircraft down to a lower altitude in the event of a decompression. If this scenario is accurate then once above 40,000 feet a very rapid loss of consciousness and death would occur to all those behind the Flight Deck door. The symptoms of Hypoxia include euphoria.

Haystacks and needles

The “experts” also stated that the aircraft might have flown slower and therefore flown further - hence more guessing as to the extent of the search area.

Rubbish.

A B777 is not a small aircraft where this can apply. The normal cruise speed of a B777 is M.84 (M is the speed of sound), high speed cruise is M.86, low speed cruise is M.82 and any slower than that, due to the high wing loading of large airliners, would result in an induced drag increase. The difference between M.84 and M.82 is very small. M is the speed of sound.

Three ships with sidescan sonar are now in the search area. It appears that the “haystack’’ has now been found and now we are searching for the ‘‘needle”.

The B777 is a very large aircraft and I personally believe that MH370 is intact and in 6000m of water. If we search long enough it will be found.

In summary the B777 is so automated that if something happened to the Flight Crew, or even if they left the cockpit shortly after takeoff, the aircraft would have flown itself to its destination via the preprogrammed computer Flight Profile.

For it to alter course and fly a different route as alleged would require the deliberate manual intervention of someone with considerable expertise of FMS protocols, which suggests a preplanned intention.