Summary
We propose to adopt a new airworthiness directive (AD) for certain Bombardier, Inc., Model DHC-8-400 series airplanes. This AD was prompted by the failure of the fire control amplifier, which was likely caused by an electrical short in a discharged squib for a fire extinguishing bottle. This proposed AD would require replacing certain circuit breakers. We are proposing this AD to address the unsafe condition on these products.