The worst news this week, from my perspective anyway, was the downing of the Russian Metrojet over the Sinai. This is absolutely awful, and my sympathy goes out to all the relatives. Immediately following the destruction of the aircraft, there were a number of statements from all sorts of places, and I find it interesting to consider why they were made. First, both Russians and Egyptians discounted “foul play”. The problem here is, both had reasons why they did not want it to be a consequence of terrorism: the Egyptians because it happened on their soil, and the Russians because they did not want it to known widely that they had been attacked. To stir the pot along, ISIS claimed responsibility, a claim that was remarkably quickly dismissed from many quarters. Personally, I think some weight should be given to this because ISIS is not in the habit of claiming what they have not done. We then heard statements that the aircraft had had a tail impact some years before. Then some Russians suddenly realized that incompetent maintenance was even worse looking for them, so they stated the aircraft was in good mechanical order. Next we have had a claim that a satellite saw an infrared flash, and following that, there appears to be evidence that those seated at the back of the aircraft alone were terribly burned. So, what can we suggest caused this? It is still too early to know, and we need more information, nevertheless an analysis of the above does make some strong suggestions, assuming the information is true.
It was not pilot error. The aircraft was apparently flying normally at 9,000 meters, then it stopped flying, quite suddenly. At that altitude there is nothing the pilot could do that would cause such a sudden failure. I also reject aircraft failure. Engineers have examined the aircraft frequently, and gross problems would have been detected. Suppose something broke, through metal fatigue. Modern aircraft have a lot of strength redundancy, as they have to fly through absolutely violent conditions. If you have ever flown through a tropical cumulus storm you will know what I mean. I have looked out the window and seen the wings flapping. If something does break, there is inevitably plenty of reserve, but suppose the reserve is in trouble. What happens then is that the failure gradually cascades, as each break adds to the problems of that remaining. However, such failures are relatively slow to develop, and the pilot would have had time to take action, such as radio for help, take power off, and try to take the aircraft lower and slower. In this case, the air conditions were very benign, which would greatly help the pilot. From what we can gather, the event was sudden and disastrous, so we can safely assume there was no problem like metal fatigue.
Similarly, we can reject an accidental collision. There is nothing to accidentally collide with at 9,000 meters.
That leaves us with two possibilities. A missile attack is one. As was shown by the Malaysian airline aircraft over the Ukraine, that is feasible. It has been argued that could not be the case because terrorists do not have access to such missiles. That may be true, but we cannot be absolutely sure. It has also been stated the satellite would have tracked the heat trail of a missile, but at this point we have to be a little careful because we do not know whether the evidence really ruled that out as we have no details of the data on which the statement was made. Perhaps it was detected, but nobody was looking at the time and there was no adequate record, or perhaps the detector was not sensitive enough.
The next possibility is an on-board explosion, which is in accord with the infrared flash, and the burnt passengers. There are three possible sources for an explosion: a missile, the fuel tank exploding, and a bomb. An explosion could result from a fuel-air mix in the tank, but that would mean that something really seriously faulty was done on the ground, because while an air-fuel mix can explode, it needs something to ignite it. The ignition temperature is so high that only a spark would do it, such as from static electricity. Aircraft fuel tanks are designed so that no such sparks can be generated.
The remaining option is a bomb loaded in with the cargo, or placed somewhere within the aircraft, either way by someone on the ground, presumably attached to the ground crew at the airport. In my opinion, this is the most likely option, but eventually we shall see. It will be reasonably easy to tell. When all the pieces of the aircraft are assembled, the source of the explosion will have led to metal being distorted away from the source. Either the fuel tank nearest the cargo deformed inwards or outwards. If inwards, it had to be a bomb. There will, of course, be other signs as well, including residues of whatever explosive was used.