The following is a possible theory based on the experience of a number of pilots who I have known for many years. They has experience on both Boeings and Airbus and extensive knowledge of flying in and around S.E. Asia. IThis is not designed to point a finger at any organisation or procedure. It is acknowledged that different countries and airlines have different rules and procedures as is their right:
Hi Keith,
The point I would like to make, before any of this goes out is this…… if the Captain was keen enough to build his own simulator, then we must or should assume he was a professional aviator, who not only enjoyed his job, but took it seriously, and also knew procedures inside and out.
It was pointed out to me by one of my colleagues, that Boeing has a new ” oxygen mask ” check procedure before each flight, this is to ensure that the oxygen is switched on in the lower cargo area, as it has , in the past been found to be switched off after deep servicing. The new procedure is to purge the line and keep the oxygen flowing for ” at Least 5 seconds ” to make sure it is switched on, as the line holds around 5 seconds worth of oxygen.
At least 2 aircraft have had a problem with this in the past and at least 2-3 aircraft have had problems after starting an emergency descent due to lack of flow….
….so this is a new Boeing directive that some companies have recently incorporated. Maybe Malaysian had not yet done it.
The Air France accident was caused by defective pitot tubes, these were known to ice up, as at least one airline had an incident with “unreliable airspeed” and after that, all operators were advised to change these pitot tubes by Airbus, I understand. Air France may not have done that …….
So a lot of things happen and sometimes can be caused by a “I don’t think it will happen to us attitude”. That may be the case in this accident.
No blame can be attributed to any one thing and for something like this to happen, it needs to be a series of problems, it needs to be smoke, alarms, possible decompression, but most of all needs to be a lack of oxygen or some further failure to lose the aircraft the way it happened.
It may have started out with a smell in the flight deck, they started to try to isolate the cause, and one of the first things you do, is mask up.
Aviate, navigate, communicate….. The captain knew that, they obviously didn’t mask up immediately, or if they did, and then found out there was no flow, he would have at that point started an emergency descent….not maybe… but guaranteed, therefore at this stage it the fumes or smoke were not that bad…
Aircraft have been lost due to fire, its the worst thing you can have, you go as fast as possible to the nearest long runway, in this case it would have been Saigon. That didnt happen, so it cant initially have been that bad, so assume no fire…..
So he decides after maybe a few minutes, that they will head back towards land, he maybe at this stage just turned the aircraft left on a heading, thats the easiest way initially.
Then it starts to get worse, the first officer is new on the 777, maybe having problems with the ” electronic checklist “ its totally new for him, to find a fumes or smoke checklist is difficult in the sim ( let alone when you are scared ) then reading it, confirming it, and checking stuff off is tricky if you dont know it well…… there are 3 different colours in the checklist, blue, green, and white, they all have reference to a different significance therefore its important to confirm each stage with the other pilot, most drills take 2 people to check and make sure its done in the correct order, otherwise stuff gets shut off that shouldnt be etc etc….
So in the meantime the Captain makes a quick decision, lets go to the nearest suitable airport with an overwater approach, he doesn’t want to fly low over land with an aircraft that may be burning, total supposition, but if he’s good he will be thinking about people on the ground..he thinks, ok we both know Penang, good long runway lets start going there…..
He now has to think about a descent and an approach into runway 04 in penang, but he cant leave the first officer to do it, the guy is already confused, scared and out of the loop, so he says something like… ok give me ” VPG ” put it to the top, and execute. done… engages LNAV and off the aircraft goes…5 secs, ok next , rather than look for the approach in the box which could take too long, he says… bring VPG back down, give me VPG/300/30, then put in VPG220/30, and execute….done, another 10 secs…..now back to the aircraft problem…back to the checklist.
What hes done now is created 2 more waypoints for the aircraft to fly itself to ( again total supposition but i would have done it a similar way ) one is on the 300 radial from penang at 30nm over the sea. once arriving at VPG, the aircraft will turn right, and head out there, he was probably thinking he would descend below safety altitude when he got overhead the beacon.
Once the aircraft reached this point, it would then turn left to a point that is 30 nm on the 220 radial from penang, which is then 30 miles on the extended centreline for runway 04 at Penang. 04 is the favoured approach, as it is overwater, and they both will have flown it many times. ( incidentally if they had also put in after each waypoint an altitude, say 25,000, once that was set in the altitude window, the aircraft would automatically leave 35,000 ft, and level off at 25,000 as it got closer to penang )…again supposition, however there are reports of the aircraft descending, this maybe why.
the point VPG/220/30 is a radial, and as the heading of the runway is 040 that is the heading you select when you go over that point) a reciprocal of 180.
between them doing that, and eventually running out of fuel 6 hours later, we dont know what happened, however we can assume that the aircraft flew the route they put in, and once it ran out of waypoints, it dropped out of LNAV into HEADING, and continued south……
They may have been overcome with fumes having not masked up fast enough, or they ran out of oxygen as it didnt flow….who knows, but whether they turned off the comms stuff or not, they didnt have time to make the call, as it was not important enough at the time…..they were flying the plane first….Aviate…
Then they navigated….after that they would have descended, gone fast, and then communicated once it was all sorted out and they were heading in the right direction…..
We know that call didn’t come.
The last point of relevance is this , if , and its only an if , the aircraft was at a lower altitude, say 25,000 ft , it would not have gone as far as it would have done at 35,000 ft, as it would burn more fuel.
All of this is pure supposition and not intended to be in any way accurate , however it may give some insight to what may have happened on the flight deck.
The main thing for people to realise, is that it was dark, late, not many aircraft around and they would have been naturally tired, as their body clocks would have been in “night mode”. In those situations anything happening is a challenge . . .
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