MHI RJ Aviation (Montréal Mirabel) is evaluating developing an ADS-B In retrofit for CRJ regional jets to enable their continued operations if a proposed regulation requiring this technology goes into force in the United States. The US FAA is contemplating such a change as a response to a 2025 midair crash on approach to Washington National. The CRJs, which are out of production, form the basis of US regional fleets, with over 600 units currently in service. There is no in-production replacement of similar size for the CRJ200 and CRJ550 variants.