 FACT: The registration number of the crashed plane is N017766, which  can be clearly seen painted on its side. All US registered aircraft  are assigned numbers beginning with the letter N. However, by FAA  rule, there can be a maximum of five numbers and/or letters  following the N. And a zero is never the first character following  the N. The zero in this case cannot be a misreading of the letter O,  because the letters O and I are never used in N