AD FAA-2020-0994

The FAA proposes to adopt a new airworthiness directive (AD) for certain Gulfstream Aerospace Corporation (Gulfstream) Model GVII- G600 airplanes. This proposed AD was prompted by a report that a failure mode in the data concentration network (DCN) software causes the pitch attitude value to freeze on the primary flight display (PFD) for up to 20 seconds. This proposed AD would require updating the DCN and flight deck master operating system (MOS) software. The FAA is proposing this AD to address the unsafe condition on these products.