The Learjet 35 is a pressurized aircraft that also is equipped with individual emergency oxygen masks for the passengers and crew if the pressurization system fails above about 12,000 feet.Tom Baum, a Learjet pilot instructor, told CNN that a panel light in the cockpit of the plane goes on if there is a problem with the pressurization and that a backup system should then automatically begin to function. He said Learjet pilots are required to wear oxygen masks around their necks.
That is an absurd statement, absolutely incorrect, and inconceivable that any pilot would ever make it.
They would never be able to sell a single one if that were true. It's like requiring all passengers to wear a parachute.
FYI, per a friend of mine who flew Lear’s for a living, they were only required to don them above flight level 410, above 40,000 feet.
The reason being there is so little time to get the mask on AND handle the emergency before you pass out when the air is that thin.