Summary
We propose to adopt a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400 series airplanes. This proposed AD was prompted by reports of two in-service incidents where one side of the main landing gear (MLG) did not achieve down-lock. This proposed AD would require a detailed inspection of the apex joints of the stabilizer brace lock link in the MLG for clearance; rectifying and repairing the clearance gap, if necessary; and lubricating the apex joints of the stabilizer brace lock link in the MLG. We are proposing this AD to detect and correct insufficiently greased stabilizer brace lock linkage of the MLG and over-torqued lock linkage attachment bolts, which could lead to the failure to extend and down-lock the MLG, and could affect the safe landing of the airplane.