It has transpired that the fate of Germanwings 9525 was suicide by the official pilot. My prayers are with the victims; the murderer---because that's what he was---was not a human, but a monster. What kind of personal tragedy justifies killing 149 innocent people, in addition to oneself? Even terrorist murder-suicides seem to have rhyme and reason behind them---this, however, wasn't a terrorist. This was a 27-year-old man from White Bread, Germany, deciding that a private suicide wasn't theatrical enough and he'd rather have his very public death, along with the deaths of 149 of his fellow men, women, and children, broadcast and picked apart on television. Normal people don't kill themselves in such a horrific fashion. They find a nice, quiet spot, perhaps write a suicide note, perhaps have a last bottle of whisky, and then shoot themselves. Andreas Lubitz was a megalomaniac deciding that if he shouldn't live, neither should anyone else around him; either that, or he was a narcissist pleading for attention. This was meticulously planned; Lubitz waited until the captain excused himself to take a leak, locked him out, and pushed down on the control stick. Captain Sondenheimer was heroic to the last, trying to break down the door with his shoulder, but it was all in vain; several minutes later, the screams of the passengers can be heard, followed by silence.
American airlines have a rule that at least two people must be in the cockpit at all times. If the pilot has to go and shake hands with his best friend Dick, a stewardess will take his place in the cockpit. European airlines are generally a bit more relaxed on the security front, which is justified, since they have a lot less to fear from terrorism. Suicide, though, is a cultural universal, as we have seen---so I think the Europeans will implement a similar rule.
The only similar flight I can recall was in the eighties (US Air, I think), although "only" 40 or so passengers died. This was caused not by a suicidal pilot, but by a murderous ticket agent in America who was sacked from his job (for theft totalling a thousand dollars or more) and decided to kill his employer and cause a PR disaster at the same time. Security protocols were extremely lax by current standards: the perp wasn't required to hand in his ID when he was fired, and it was this that enabled him to board a flight with a gun, kill his manager, both pilots, and an additional pilot in the passenger section of the plane, and then force the aircraft into a dive. The company could have prevented the disaster: David Burke was notoriously violent, had seven children and no domestic relationship, and, to top it all off, he was a Jamaican who had been using US Air to smuggle cocaine from Jamaica to Rochester.
I hope their souls rot in hell.