[Federal Register: June 30, 1998 (Volume 63, Number 125)] [Proposed Rules] [Page 35647-35648] From the Federal Register Online via GPO Access [wais.access.gpo.gov] [DOCID:fr30jn98-40] [[Page 35647]] _______________________________________________________________________ Part II Department of Transportation _______________________________________________________________________ Federal Aviation Administration _______________________________________________________________________ 14 CFR Part 23 Airworthiness Standards; Occupant Protection Standards for Commuter Category Airplanes; Proposed Rule [[Page 35648]] DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 23 RIN 2120-AD27 Airworthiness Standards; Occupant Protection Standards for Commuter Category Airplanes AGENCY: Federal Aviation Administration, DOT. ACTION: Notice of proposed rulemaking (NPRM); withdrawal. ----------------------------------------------------------------------- SUMMARY: The FAA is withdrawing a previously published Notice of Proposed Rulemaking (NPRM) that proposed to amend the airworthiness standards for normal, utility, acrobatic, and commuter category airplanes. That notice proposed an upgrade in the requirements for both seat/restraint systems and for flammability standards for seat cushions used in commuter category airplanes. It also proposed an increase in the downward inertia load factor for items of mass within the cabin for all normal, utility, acrobatic, and commuter category airplanes. The FAA is developing a new proposal based on information gathered subsequent to the NPRM. DATES: This proposed rule is withdrawn as of June 30, 1998. FOR FURTHER INFORMATION CONTACT: Michael Downs, Standards Office (ACE- 111), Small Airplane Directorate, Aircraft Certification Service, Federal Aviation Administration, 601 East 12th Street, Kansas City, Missouri 64106; telephone (816) 426-5688. SUPPLEMENTARY INFORMATION: On July 14, 1993, the FAA published Notice of Proposed Rulemaking No. 93-71 (58 FR 38028) to propose an amendment to 14 CFR part 23 and invited public comment. During the comment period, the General Aviation Manufacturers Association (GAMA) objected to the proposed rule. GAMA's September 17, 1993, letter to the docket stated the following: ``The docket for the rule did not contain data on several recent accidents of 10-19 passenger airplanes operated under 14 CFR part 135 rules, which indicated that those accidents occurred at crash conditions approaching those of a flat impact crash. The FAA considered it necessary to evaluate the flat impact crash condition when conducting the analysis leading to the proposals in this notice. Because FAA bases certain of the criteria in this proposal on these data and analyses therefore, industry cannot appropriately comment on this proposal until the supporting data are made available for public evaluation.'' The report GAMA referenced, ``Commuter Airplane Accident Data Analysis,'' was published in August 1994. The FAA reopened the comment period on November 4, 1994; it closed on March 4, 1995. Many of the general comments addressed the accuracy of the derived safety benefits of the rule and questioned how the safety benefits could be evaluated independently from the benefits expected of other recently adopted rules. Several commenters questioned the use of a 15- year life expectancy for seats utilizing fireblocking materials when their commercial experience indicated an average life expectancy of four years. On March 29, 1995, Notice No. 95-5, ``Commuter Operations and General Certification and Operations Requirements,'' was published. This rulemaking effort proposed, in part, to move all scheduled part 135 operations with ten passenger seats or more to 14 CFR part 121 operations and for newly type certificated airplanes operating in accordance with part 121 to be type certificated under part 25. Since most airplane manufacturers of part 23 commuter category airplanes design their airplanes to be operated in accordance with part 135, the proposed rule affected the applicability of part 23 certification requirements for airplanes operating in scheduled service with ten or more passenger seats. On January 19, 1996, the ``Commuter Operations and General Certification and Operations Requirements'' final rule was adopted as amendment 121-151. As a result, the FAA re-evaluated the cost analysis for Notice 93-71. With the removal of scheduled part 135 aircraft, the proposed amendment would no longer be cost-beneficial. With the adoption of amendment 121-151, the projected benefits of the dynamic seat testing and flammability requirements proposed in Notice No. 93-71 have been negated. Other commenters addressed the stringency of the proposed rule when compared to the existing requirements for similarly sized small transport category airplanes. The FAA cannot agree that such a comparison is valid. The 14 CFR part 25 transport category airplane seat dynamic performance standards were defined using data that were representative of the impact response characteristics of large (narrow or wide body) transport category airplanes. The structural depth under the floor and impact energy absorption characteristics of these airplanes is considerably greater than that for commuter category airplanes and small transport category airplanes. In light of these differences, the use of part 25 transport category airplane standards for commuter category airplanes would not provide adequate protection. The FAA is considering amending both part 23 and part 25 standards to make them consistent for commuter category and small transport category airplanes. Additional comments stated that the maximum acceleration levels proposed were unrealistically high and would require excessive energy absorption designs. The FAA disagrees. Energy absorbing seats have been designed and tested at the Civil Aeromedical Institute (CAMI) to the combined longitudinal and vertical test conditions found in Notice No. 93-71, and those seats met the requirements of the proposed rule. Those tests demonstrated that the minimum requirements for providing occupant spinal column/pelvic load protection can be provided with seats that have four inches of seat stroke or energy absorption capability. Full- scale commuter category airplane impact tests conducted with the CAMI energy absorbing seats on board have confirmed the above CAMI test lab finding. In consideration of those comments to Notice No. 93-71 regarding the cost-benefit analysis and the effect of amendment 121-151, the Federal Aviation Administration has decided to withdraw Notice No. 93- 71. Instead, the FAA is planning to task the Aviation Rulemaking Advisory Committee (ARAC) to amend both part 25 transport category airplane standards and part 23 to make them consistent for commuter category and small transport category airplanes. In addition, the FAA plans to initiate a new rulemaking project to propose seat cushion fireblocking provisions for new type certificated commuter category airplanes. Accordingly, Notice No. 93-71, published on July 14, 1993 (58 FR 32028), is withdrawn. Issued in Washington, DC on June 22, 1998. Thomas E. McSweeny, Director, Aircraft Certification Service. [FR Doc. 98-17291 Filed 6-29-98; 8:45 am] BILLING CODE 4910-13-M