Major airworthiness directives related to aircraft systems aren’t all that uncommon, but a new AD issued by the FAA yesterday that calls for the replacement of the primary flight displays in certain Boeing 737 and 777 airliners raises eyebrows not just for what must be replaced but also the reason why.
The FAA on October 1 posted AD 2014-20-06 related to all Boeing 737-600, -700, -700C, -800, -900, and -900ER series airplanes and 777 airplanes with Phase 3 Honeywell displays. The directive was prompted by testing reports on certain Honeywell PFDs that exhibited susceptibility to radio interference from Wi-Fi frequency bands.
