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Notice of proposed rulemaking (NPRM).

The FAA proposes to adopt a new airworthiness directive (AD) for certain THOMMEN AIRCRAFT EQUIPMENT AG (THOMMEN) AC32 Digital Air Data Computers. This proposed AD results from occurrences of AC32 Digital Air Data Computers (ADCs) that stop functioning below certain temperatures. This proposed AD would require replacing an affected AC32 Digital ADC with a serviceable part. The FAA is proposing this AD to address the unsafe condition on these products.

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