Define “modern”.…Don't modern planes have a lot of nanny features to prevent you from doing acrobatics like: "push down all the way, roll upside down, and pull up" to achieve a vertical nose dive? I tried these crazy maneuvers an a Falcon 7X simulator (real cockpit, hydraulics etc.) and got the thing to go upside down, but the computer would not let you do it unless you overpowered it multiple times and there were alarms blaring everywhere. Suicide would make sense if those features had to be overridden otherwise some type of mechanical failure / disintegration of the control surfaces?
It is more a matter of fly by wire, which enables flight control laws and envelope limitations, than date of manufacture.
Nobody would call a Citation modern.
The pilot suicide that took place in 2016, on Germanwings 9525, happened on a “modern” airliner, the A-320, which has full flight envelope protection built into its fly by wire system.
The nanny features made no difference.
Germanwings Flight 9525 - Wikipedia
en.wikipedia.org