Inconsistencies between the Mitsubishi MU-2B elevator trim indicator scale dial and the elevator trim mechanical stop have prompted the FAA to issue an airworthiness directive, requiring owners to modify the scale dial so that it is consistent with elevator trim capability. The inconsistency has led to several incidents in which pilots mistakenly assumed that more nose-down trim was available and inadvertently jammed the trim system. “Attempting to force additional nose-down trim beyond the mechanical stop may jam the trim system, preventing subsequent electric trim changes until the pilot manually frees the trim wheel,” the FAA stated. AD 2007-17-09 takes effect September 25 and is required within 100 hours time-in-service after that.