The US Federal Aviation Administration (FAA) has proposed a new airworthiness directive mandating modifications to all MHI RJ Aviation CRJs operated in the country to prevent 5G interference.

The proposed rule would affect all operators of CRJ100, CRJ200, CRJ550, CRJ700, CRJ705, CRJ900, and CRJ1000 types in contiguous US airspace. The FAA intends to require the installation of a new radio frequency (RF) bandpass filter on the coaxial line between the radio altimeter and the receive antenna in the aft equipment compartment to prevent radio altimeter interference caused by 5G waves, which could lead to unsafe conditions during landings. The requirement mimics a similar rule issued by Transport Canada in November 2023.

The FAA estimates the cost of implementation will amount to around USD60,000 per aircraft, totalling up to USD51.1 million for all operators of the around 837 affected aircraft. However,it pointed out that some of the aircraft may already be compliant.

The ch-aviation fleets module shows that the largest operators of CRJs in the United States are SkyWest Airlines (294 aircraft), Endeavor Air (189), and PSA Airlines (141).

The implementation of 5G broadband in the United States in early 2022 caused significant, albeit brief, disruption around airports, given the dangers the interference posed to some aircraft systems in particular during approach and landing.