Summary
We propose to adopt a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-100, DHC-8-200, and DHC-8-300 series airplanes. This proposed AD was prompted by reports of hydraulic accumulator screw cap or end cap failure. This proposed AD would require replacing the affected parking brake accumulator. We are proposing this AD to prevent failure of the parking brake accumulator screw caps or end caps, which could result in loss of the number 2 hydraulic system and damage to airplane structures, and could potentially have an adverse effect on the controllability of the airplane.