Summary
We propose to supersede an existing airworthiness directive (AD) that applies to certain Bombardier, Inc. Model CL-600-2B19 (Regional Jet Series 100 & 440) airplanes. The existing AD currently requires revising certain sections of a certain airplane flight manual, deactivating certain hydraulic accumulators, removing certain hydraulic accumulators, ultrasonic inspections for cracks on accumulators and screw caps and replacement if necessary, and replacing certain accumulators. Since we issued that AD, we have determined that, for certain airplanes, reducing the compliance time for a certain replacement is necessary to ensure that the identified unsafe condition is addressed. This proposed AD would continue to require the existing actions from the existing AD. We are proposing this AD to detect and correct hydraulic accumulator screw cap/end cap failure, which could result in the loss of the associated hydraulic system and high-energy impact damage to adjacent systems and structure, and consequent loss of control of the airplane.