New FAA guidance has attracted comment from the Modification and Replacement Parts Association (MARPA). FAA order 8110.42D on parts manufacturer approval procedures, which cancelled revision C was published this month. MARPA noted that the guidance in relation to the FAA’s Risk Based Resource Targeting (RBRT) tool relied on subjective assessments that could result in unfair treatment on certain Part Manufacturer Approval projects. The FAA agreed the RBRT tool was not ready for prime time and removed it from the order. MARPA also commented on FAA AC 21.303-2, and asked the FAA to address expected sample sizes. The FAA has agreed to do so.