Pro Aire Cargo & Consulting, Inc.

I operate one of the largest commercial fleets of Cessna 310 aircraft (10) in the country and I believe that the NPRM on the twin Cessna icing AD is one of the most arbritary and capricious pieces of legislation to come about in some time. The NPRM states that there have been 52 accidents over the past 30 years involving aircraft covered by the NPRM, but does not state how many icing accidents occurred with aircraft of the exact same type that are not covered by the NPRM. So there is no correlatiing information as to whether or not the older aircraft are really more likely to be involved in an icing accident. In addition there is no information as to how many of the accidents were private owner/operators compared to commercial operators who typically have more frequent and thorough training programs. The NPRM states that later models of the affected aircraft incorporated new and improved equipment. The fact is that there is no difference in deice equipment p/n's on a Cessna 310 s/n 735 vs 801 or a Cessna 402B s/n 640 vs 801. In fact there are very few p/n differences on the whole aircraft so how can there be any noticeable difference in flight characteristics. The most arbritary fact of all in this NPRM is that it only affects twin Cessnas and not the numerous Beech and Piper aircraft that are also not certified for known ice but whose operation would be unaffected. In one of the craziest inconsistencies of this NPRM an operator with a Cessna 402B(an aircraft type certified for known ice) s/n < 801 would be unable to operate this aircraft while an operator of a Cessna 207 (An aircraft never certified by Cessna for known ice) with deice boots slapped on it would be able to operate as normal per 135.227 and 91.9. I urge the FAA to rethink this NPRM and leave the decision of operating these fully deiced aircraft of lower serial numbers to the POI's and PMI's of the operators affected if there seems to be any legitimate safety concerns involving some of them.