Experts said the equation could be used by a pilot to calculate the rate of descent to hit a target on the horizon.

Speaking with the help of a translator he said: “Perhaps this was an equation that we studied before in high school, and I was trying to remember whether I’m going to be able to figure out and solve it or not.”

He also met 9/11 hijackers Nawaf al-Hazmi and Khalid al-Mihdhar in Los Angeles in early 2000, however, he claims this was just a chance encounter and he was helping them settle into the US.

Following the attacks, Bayoumi relocated to Saudi Arabia and has never been charged with any crime.