Summary
We propose to adopt a new airworthiness directive (AD) for certain General Electric Company (GE) CT7-8A and CT7-9B model turboshaft engines. This proposed AD was prompted by reports from the manufacturer that the high-pressure compressor (HPC) impeller installed on these engines may have suffered from material degradation during the manufacturing process. This proposed AD would require removal of the affected HPC impellers. We are proposing this AD to address the unsafe condition on these products.