Michael Donahue

In reviewing the proposed superseding AD to AD 2007-17-07, I have the following comments: Proposed paragraph (g)(3) I do not believe this should be required. Bombardier and the flap actuator manufacturer (Eaton) are very close to certifying a new seal for the flap actuator. This is to fix the internal fluid leakage issue in the actuator which could result in an actuator problem (and result in the actuator failing the low temperature torque test). Once this is certified, a fleet retrofit with the modified actuator would result in a more robust fix for the actuator issue. There is no guarantee currently that a replacement actuator installed to replace an actuator failing the low temperature torque test would not have the same issue shortly after installation (negating the benefit of performing the test). The flight operations requirements instituted under AD 2007-17-07 provide an acceptable margin of safety until the modified actuator becomes available for retrofit. Mike Donahue Chief Engineer Mesaba Airlines