Airworthiness Directives; Bombardier Model DHC-8-100, -200, and -300 Series Airplanes

This amendment adopts a new airworthiness directive (AD), applicable to certain Bombardier Model DHC-8-100, -200, and -300 series airplanes, that requires revision of the applicable maintenance program manual, repetitive inspections for corrosion or cracking of the hook roller shafts of the flap carriage, and eventual replacement of the hook roller shafts with new or serviceable hook roller shafts. This replacement extends the interval for the repetitive inspections. This action is necessary to prevent cracking of the hook roller shafts of the flap carriage and consequent reduced structural integrity of the flap, which could result in jamming of the flap. This action is intended to address the identified unsafe condition.