"Japan Airlines 350
Japan Airlines Flight 350 - Wikipedia, the free encyclopedia
Royal Air Maroc flight 630
Royal Air Maroc Flight 630 - Wikipedia, the free encyclopedia
Silk Air flight 185
SilkAir Flight 185 - Wikipedia, the free encyclopedia
EgyptAir 990
EgyptAir Flight 990 - Wikipedia, the free encyclopedia
Linhas Aéreas de Moçambique - LAM 470 LAM Mozambique Airlines Flight 470 - Wikipedia, the free encyclopedia"
Regarding the pilot suicide theory: 5 instances in 30 years is statistically equivalent to none at all.
Say there are 100,000 or so pilots working for all the airlines on the planet at any given time. The average suicide rate in countries developed enough to have airlines of any size is, at best, a guess, but 10 per 100,000 would seem reasonable based on
this chart (which is based on World Health Organization data from 2011). Given that a large majority of pilots are men, and male suicide rates are generally higher, 10 per 100,000 may even be low.
So, over a 30-year period, there would have been approximately, and at least, 3,000 suicides by airline pilots. 5 of those might have been suicide-by-loaded-aircraft. Statistically that's zero plus noise. And none of those five seem to have involved the kind of advance planning and convoluted thinking that would be required in this case.
No, that's not dispositive. Yes, pilot suicide has to be considered as a possibility, based on what's known to date. But I suspect we would have heard days ago if there was any real evidence to suggest that pilot suicide was really plausible, as opposed to simply one of many possibilities.
It's worth noting, by the way, that Malaysia has the third-lowest suicide rate of the 192 countries listed.