From hypoxia to fire, aviation experts’ take on what happened on MH370

A British aviation society portal has sought the opinion of experts about what might have happened on board MH370 and the various theories that had come forward since the plane vanished from civilian radar on March 8. – File pic.

It has been exactly three weeks since Malaysia Airlines flight MH370 disappeared and numerous theories for the incident have been put forward.

A British aviation society portal has asked industry experts attending a recent conference in London for their take on the reasons behind MH370's disappearance.

"The Flight Operations Group (FOG) recently held a two-day conference in London on the subject of the role of aircraft commander in the 21st century," reported the British Royal Aeronautical Society website aerosociety.com.

"The conference included speakers who represented pilots, airlines, manufacturers and regulators," the portal reported.

Aerosociety.com sought the opinions of these experts about what might have happened on board MH370 and the various theories that has come forward since the plane vanished from civilian radar on March 8.

Below are excerpts from the report.

What are your views on these alternative theories?

1. The aircraft depressurised but continued to fly

It’s possible. This would explain the initial change in altitude and heading, as well as subsequent lack of communication but not why the ACARS and transponder were turned off.

2. The aircraft was overcome by toxic fumes

Unlikely. The pilots should have been able to send out a distress call and, again, it does not explain why the ACARS and transponder were turned off.

3. There was an onboard fire which damaged the communications systems

Again unlikely. This would explain the lack of communication but it is unlikely that the aircraft would have then continued to fly as long as it did if the fire continued to burn.

4. The aircraft was hijacked

A possible theory but the aircraft was not flown to another destination nor was it used as a weapon for a suicide terrorist attack. If it was an individual hijacker, then no one person or motive has been established and, if it was a group, no organisation has claimed responsibility.

5. The aircraft was deliberately diverted by the pilot/co-pilot

Possible again but no reason for this has not been identified. If it was a suicide attempt then why did the aircraft continue to fly for so long?

Technical questions

1. How easy is it to turn off ACARS and transponder?

Turning off the transponder can be done from the cockpit and is done routinely whenever aircraft have landed. Turning off ACARS is more complicated and would need someone with systems knowledge having to go into the aircraft’s avionics bay.

2. Could the aircraft’s communication systems have been disabled by any other means – such as fire/birdstrike/power failure/sabotage by third party from avionics bay?

Birdstrike is unlikely to have caused such damage but the other explanations are all possible. It is possible to disconnect communication systems from avionics bay but this should have been prevented if security was adequate.

3. The IFE moving map would have shown that the aircraft was going off course. So why were there no mobile phone calls sent from passengers or cabin crew aboard flight?

The IFE map may have been turned off. Most of the passengers may have been asleep and not realised anything was wrong until it was too late to do anything.

If they tried to phone later in the flight, the aircraft would have been in a remote area over the ocean where there was no signal.

Alternatively, the passengers and cabin crew may have been incapacitated in some way, such as by hypoxia due to cabin depressurisation.

4. How long could the aircraft be flown if depressurised?

The aircraft could continue to fly automatically untiI the fuel ran out. The effect on the people on board would vary depending on the altitude of the aircraft.

If the aircraft was above 10,700m, it would take about one minute before everyone was incapacitated. However, if the aircraft had depressurised, oxygen masks for the passengers should have descended automatically which would work for around 15 minutes.

The flight crew could have lasted longer using oxygen masks depending on whether they used pure oxygen or an oxygen mix.

4. Could either the data or the homing beacon on the ‘black boxes’ be tampered with during flight?

No. The cockpit voice recorder (CVR) and flight data recorder (FDR) cannot be tampered with.

5. Could data from aircraft still be sent to satellite if aircraft had landed/crashed in sea?

No.

6. The RAeS Flight Operations Group has written a report about dangers of lithium-ion batteries as cargo. Could they be responsible for a fire?

Possible but unlikely. It has been reported that lithium batteries were being carried in the rear hold of the aircraft but the aircraft is unlikely to have continued flying for so long if a fire had broken out. It also does not explain why the communication systems were turned off.

7. What happens when an aircraft flying on autopilot comes to the end of a FMS waypoint? Carry straight on, circle etc?

There are options for the aircraft to either continue on its current heading and to begin circling.

8. Is live (or triggered) streaming of black-box data feasible?

Yes, it can be done but it would be very expensive for an airline to fit such systems to every aircraft in its fleet.

9.   What do you think will be the implications of this incident for the aviation industry?

-    A change in ATC procedures as to when an aircraft must make contact.
-    Improved communications between different international civil and military organisations.
-    All airlines need to have 'crisis cell' which is activated for aircraft accidents.
-    Aircraft positions and status could be transmitted regularly to airline and manufacturers – but systems would be expensive to install.

Aerosociety.com noted that one technical expert pointed out that for every plausible reason suggested above, there was at least one contradictory statement.

"If it was hypoxia, then who turned MH370 around?"
"If it was a fire, then how did the aircraft continue flying?"
"If it was the flight crew, then why did the cabin crew not intervene?"

The technical expert told the portal that perhaps more than one scenario occurred simultaneously, such as wiring fire and depressurisation.

However, one thing is for certain, until more evidence is found, nothing can be proved. – March 29, 2014.