Airworthiness Directives; Bombardier Model DHC-8-101, -102, -103, -106, -201, -202, -301, -311, and -315 Airplanes on Which Engine Oil Coolers Have Been Installed Per LORI, Inc., Supplemental Type Certificate (STC) SA8937SW

This amendment adopts a new airworthiness directive (AD), applicable to certain Bombardier Model DHC-8-101, -102, -103, -106, - 201, -202, -301, -311, and -315 airplanes on which engine oil coolers have been installed per LORI, Inc., STC SA8937SW. This amendment requires an inspection or a review of the airplane maintenance records to determine the part number and serial number of each engine oil cooler, and replacement of certain engine oil coolers with reworked engine oil coolers. This action is necessary to prevent oil leakage from the engine oil coolers, consequent in- flight engine shutdown due to low oil pressure, and reduced controllability of the airplane. This action is intended to address the identified unsafe condition.