Complex sentence: Both the YC-14 and YC-15 both generally met the specifications of the contest, the increasing importance of the strategic vs. tactical mission eventually led the Air Force to conclude that they were better off with an updated C-130.
Split into simpler sentences: Both the YC-14 and YC-15 both generally met the specifications of the contest. The increasing importance of the strategic vs. tactical mission eventually led the Air Force to conclude that they were better off with an updated C-130.