The old ones just added oxygen to a tank and used it. The new ones that are screwing up are some zippy trendy catalytic oxygen generator system that works pretty well....sometimes. Other times it asphyxiates you or poisons you in a manner that the pilot has a tough time realizing it before they pass out.
But its really modern.
The Man From LOX. https://www.youtube.com/watch?v=rUKcHe0-m_I
“The old ones just added oxygen to a tank and used it. The new ones that are screwing up are some zippy trendy catalytic oxygen generator system that works pretty well....sometimes. Other times it asphyxiates you or poisons you in a manner that the pilot has a tough time realizing it before they pass out.”
And you may recall that a baggage compartment with some of these canisters set themselves on fire and brought down a commercial DC-9 in Florida a few years ago.