Summary
We propose to adopt a new airworthiness directive (AD) for all The Boeing Company Model 787 series airplanes. This proposed AD was prompted by a report of an uncommanded descent and turn that occurred after an inflight switch to the spare flight management function (FMF). This proposed AD would require an inspection of the flight management system (FMS) to determine if certain operational program software (OPS) is installed and installation of new FMS OPS and a software check if necessary. For certain airplanes, this proposed AD would also require concurrent actions. We are proposing this AD to address the unsafe condition on these products.