Summary
We propose to supersede Airworthiness Directive (AD) 2015-23- 12, for all ATR--GIE Avions de Transport Regional Model ATR42 and ATR72 airplanes. AD 2015-23-12 currently requires identifying the serial number and part number of the main landing gear (MLG) rear hinge pins, and replacing pins or the MLG if necessary. Since we issued AD 2015-23-12, we have received a new report of a certain cracked MLG hinge pin on a Model ATR42 airplane. We have determined that certain additional MLG hinge pins must be replaced, and certain compliance times must be reduced. This proposed AD would require identifying the serial number and part number of the MLG rear hinge pins, and replacing pins if necessary. We are proposing this AD to address the unsafe condition on these products.