MH370 UPDATE

Saturday, 29 March 2014

WHAT HAPPENED TO MH 370

The likely B-777 scenarios are narrowing down to just one

When the Malaysia Airlines Boeing 777 vanished almost a month ago speculation was rife about its fate: Suicide, terrorism, criminal acts by passengers or crew, hostage taking, catastrophic structural failure (something that has never happened to a 777 in its 20 year history) were all on the table.

Although widely criticized as incompetent and dishonest, the authorities were wise to play their cards slowly while some form of criminality was considered highly likely. To do otherwise may have played right into the hands of those responsible. But the likelihood of criminal interference, or criminal actions by the pilots, are now receding.

Much news media mileage has been made of the captain’s flight simulator, but lots of pilots have their own simulator and many former pilots regularly ‘fly’ on a simulator. In my own case I’ve spent many hours on various Boeings including the 777. It’s not uncommon to indulge in flight activities that would be most unwise in the real aircraft. For example I sometimes simulate returning to the airport after all power is suddenly lost during climb out at 15,000 to 20,000 feet. Large jets are capable of gliding much further than many people would imagine.

Simulators, airline and private, have have done a lot to make flying safer. They keep pilots ahead of the game, and it’s my belief that the Malaysian pilots were right up with the game until fate took a hand. Every pilot worthy of the title will always fly with an instant action plan in mind to cover every possible emergency.

In the flight plan there may be only one alternate airport for diversion in the event that the destination cannot be used. But every minute of the flight the crew will always know the location of the nearest suitable landing place, and in a life and death emergency turning toward that airport will be the first priority.

We know now that shortly after the last communication the aircraft suddenly turned from a northerly heading to a south westerly heading on a course that would take it into the southern 

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Indian Ocean. But that heading also pointed the aircraft to a 13,000 foot runway in Malaysia that was closer than the departure airport.

The next actions should have been to start the descent and transmit a distress call. The rule is Aviate Navigate and Communicate, in that order. The autopilot would have been used to turn the aircraft onto the new heading and the altitude bug may have been turned off while the pilots selected a new flight level and rate of descent. But programming the autopilot may have been interrupted when the pilots were suddenly incapacitated.

The likely culprit must be decompression, poisonous fumes of some kind; a smoldering tire, or fumes from the consignment of troublesome batteries that were in the cargo hold. The fumes from those batteries can kill within 10 seconds.

So we have a situation where the aircraft is trimmed for the turn (slightly nose up) and is being flown partly manually and partly by autopilot. If the pilots are unconscious at the completion of the turn the aircraft will climb. This may explain why it climbed 10,000 feet above its assigned altitude. At 45,000 feet the 777 would be struggling to fly and left to its own devices the nose would drop quite steeply. As it gained airspeed again it would have leveled off and and started another climb. This may explain the sighting of a jet airliner flying low and fast over the Malaysian Peninsula around the time that MH 370 would have been crossing.

The process may have taken several oscillations before normal flight resumed on the new selected heading, possibly with the altitude increasing slowly as the fuel load burned off. It all depends on the actual settings for the autopilot; heading we can be fairly certain of, but airspeed, altitude and power settings will only ultimately be revealed when the black box is recovered. It is possible that the airspeed at the top of the climb may have been very close to the minimum airspeed to remain airborne, or close to the point of stall. 

When the aircraft ran out of fuel it is likely that one engine failed before the other and the asymmetric thrust at the low air speed would probably disengage the autopilot completely. The remaining engine would wind the aircraft into a graveyard spiral with the airspeed then increasing very rapidly.

The cockpit of a Boeing 777. The autopilot controls are at the top center of the panel

If the last engine failed a few seconds after the first it would make little difference. Once in the spiral without a conscious pilot at the controls the aircraft would in all probability disintegrate before hitting the sea.

In aviation anything is possible once. In most other fields of endeavor the same mistakes can happen over and over again, but aviation is different. Aviation learns from its mistakes. That is why flying is safe.

But that is no consolation for the victims and their loved ones. However, if my scenario is the correct one, then the suffering was probably very brief.

UPDATE
30th July 2015

Wreckage, possibly from MH370, has been found washed up on Reunion Island in the western Indian Ocean, several thousand kilometres from the search area south west of Perth in Western Australia.

So, was the search being conducted in the wrong place? Possibly not. A study of the ocean currents tends to confirm that wreckage from the search area could indeed be carried on a circuitous route north, west and then south to the area of the find.

Indian Ocean currents/Wikipedia

If the wreckage found is confirmed as coming from MH370 then is can be expected that other wreckage may be scattered over a wide area of the ocean, the drift depending on shape and weight of individual items. For the flaperon to detach from the aircraft, the way it must have, indicates that there may be dozens, perhaps hundreds, of small pieces of wreckage, indicating a possible break-up in the air, possibly in a graveyard spiral after fuel exhaustion. 

This must be regarded as the most significant clue so far in the search for the missing airliner, and those on board.