PRODUCT: Certain Bombardier Inc. Model DHC-8-400 series airplanes. SUBJECT: Airworthiness Directive 2012-18-15 ACTION: Final Rule
SUMMARY: This AD was prompted by reports that the automatic de-icing mode became unavailable due to a failure of the timer and monitor unit (TMU). This AD requires replacing the TMU.
The FAA is issuing this AD to prevent loss of the automatic de-icing mode and consequent increased workload for the flightcrew, which, depending on additional failures, could lead to loss of control of the airplane.
DATES: This AD becomes effective October 22, 2012.