Originally Posted by
AGBagb
The first two are obvious (any military jet, just for one). The second is of course a very good point (also made later by another poster).
Just trying to get a handle on the airline saying "external influence" as a cause, and the range of what that might mean.
Possibly intended meaning has not been correctly conveyed in the literal translation of "influence" from Russian to English.
A better translation would have been "external factors". Airframe, systems, engines and crew are discounted as being a cause or contributory factor. When these are then viewed against the background of sudden loss of speed and altitude, the disposition of the wreckage, the only causes left must be external factors. Examples of which are, some kind of severe wx phenomena, bird strike, explosives on board ( not necessarily pax related, but also cargo related) and finally a missile strike. This last less likely, given that in the case of MH17, where a BUK system is suspected, the disposition of the wreckage bears little resemblance to this one. I am afraid if comparisons are to be made this one seems closer to the Pan Am Lockerbie disaster, where the break up sequence was such that the centre section came straight down and the debris field was wide with the cockpit and tail sections remaining relatively intact. That also occurred not long after the aircraft had reached its cruise altitude.
The mid-air separation of both the nose and tail sections (both free of any signs of fire damage ) of the aircraft from the mid section of the fuselage with both wings remaining attached in its fall, exhibiting an intense fuel fed combustion, leaves little doubt that the external factor referred to was an expansion of flammable gases of a large magnitude, generating sufficient linear forces to cause relatively uniform breaks of the fuselage at its two major structural assembly stations (hoop stress is four times that of lateral stress) This would further suggest that the origin of such a force is most likely to have been situated in the centre section of the fuselage, possibly close to the centre fuel tank, with its attendant fuel vapour.