Anonymous

The proposed definition relaxation will result in blending the Cat III operational and system performance distinctions, and appears to ignore the potential reduction in safety. Aircraft and flight crews are certified with systems that are either fail-passive or fail-operational. Presently, CAT III fail-passive aircraft and crews are restricted to a DH of 50 feet and RVR of 700. With the definition relaxation, aircraft and crews restricted to DH 50 and RVR 700 will automatically be qualified to minimums that are now only permitted with fail-operational crews and equipment. In other words, fail-passive systems and flight crews trained to the fail-passive minimums and procedures will be permitted to fly to fail-operational minimums. Is this safe? I could not find reference to a safety assessment in the commentary presented in the docket. A safety assessment of the changes should be accomplished to assure that there is no safety degradation that could harm the flying public.