1655 Jet A-1 ASTM-D 1655 Wee49catkew,....fiani The certification basis for this modification is as follows: The original certification basis for the Hawker Beecheraft Model 400A airplanes identified on TCDS AI6SW, Revision 26, dated March 17, 2010: Part 25 of the Federal Aviation Regulations effective February 1, 1965,