Summary
We propose to adopt a new airworthiness directive (AD) for PILATUS AIRCRAFT LTD. Model PC-12/47E airplanes. This proposed AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as an error within the flight management system caused by installing Primus APEX software Build 10 or 10.9, which could cause deviation from the correctly calculated barometric vertical navigation nominal glide path. We are issuing this proposed AD to require actions to address the unsafe condition on these products.