FAA is proposing a new airworthiness directive (AD) for the replacement of certain older Honeywell cockpit displays on Boeing 737 and 777 family aircraft due to their vulnerability to Wi-Fi interference.
The agency said the Honeywell phase 3 display units (DU) are susceptible to radio frequency emissions in Wi-Fi frequency bands at "radiated power levels below the level that the displays are required to tolerate for certification of Wi-Fi system installations."
During testing of the phase 3 DUs on 737 series aircraft, the displays went blank for as long as 6 minutes when subjected to Wi-Fi frequencies. If the systems were to go blank during takeoffs and landings, it could result in the flight crew's loss of control of the aircraft at altitudes insufficient for recovery, FAA said. The displays provide flight critical information such as airspeed, altitude and heading.
According to FAA, the AD affects 157 aircraft, with a total cost of retrofitting the planes with new displays at $1.6 million, or about $20,000 per plane.
Boeing reportedly addressed the problem with affected operators in 2012, but has not indicated how many aircraft have had their displays replaced. Honeywell did not return calls for comment.
Related: Commercial Avionics News