Notebook tied to associate of 9/11 hijackers said to contain plane drawing, flight calculations

Two decades after the 9/11 terrorist attacks, a new two-page declaration has become part of both the ongoing litigation by the families of 9/11 victims against the Kingdom of Saudi Arabia and their effort to declassify the underlying FBI records that may show any possible Saudi government officials' assistance to the hijackers prior to September 11, 2001.

The FBI twice quizzed an American pilot in 2012 about a notebook recovered from the home of a close associate of two 9/11 hijackers. The notebook contained a handwritten drawing of a plane and mathematical equation that might be used to view a target and then calculate the rate of descent to the target, according to a sworn declaration expected to be filed soon in in federal court and obtained by CBS News.  "I shared with the FBI my opinion that there was a reasonable basis to believe that the drawing and equation were used as part of the preparations of the al Qaeda terrorists to carry out the 9/11 attacks," Navy veteran and pilot Robert M. Brown wrote.