[Federal Register Volume 61, Number 129 (Wednesday, July 3, 1996)] [Rules and Regulations] [Pages 34716-34718] From the Federal Register Online via the Government Publishing Office [www.gpo.gov] [FR Doc No: 96-16959] ======================================================================= ----------------------------------------------------------------------- DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 25 [Docket No. NM-127; Special Conditions No. 25-ANM-117] Special Conditions: Cessna Model 500, 550, and S550 Airplanes; High-Intensity Radiated Fields AGENCY: Federal Aviation Administration, DOT. ACTION: Final special conditions; request for comments. ----------------------------------------------------------------------- SUMMARY: These special conditions are issued for the Cessna Model 500, 550, and S550 airplanes. These airplanes, as modified by Columbia Avionics, Inc., utilize new avionics/electronic systems, such as an electronic flight information system (EFIS), which perform critical functions. The applicable regulations do not contain adequate or appropriate safety standards for the protection of these systems from the effects of high-intensity radiated fields (HIRF). These special conditions contain the additional safety standards that the Administrator considers necessary to establish a level of safety equivalent to that established by the existing airworthiness standards. DATES: The effective date of these special conditions is June 20, 1996. Comments must be received on or before August 2, 1996. ADDRESSES: Comments on these special conditions may be mailed in duplicate to: Federal Aviation Administration, Office of the Assistant Chief Counsel, Attn: Rules Docket (ANM-7), Docket No. NM-127, 1601 Lind Avenue SW., Renton, Washington, 98055-4056; or delivered in duplicate to the Office of the Assistant Chief Counsel at the above address. Comments must be marked: Docket No. NM-127. Comments may be inspected in the Rules Docket weekdays, except Federal holidays, between 7:30 a.m. and 4:00 p.m. FOR FURTHER INFORMATION CONTACT: Mark Quam, FAA, Standardization Branch, ANM-113, Transport Airplane Directorate, Aircraft Certification Service, 1601 Lind Avenue SW., Renton, Washington, 98055-4056; telephone (206) 227-2145; facsimile (206) 227-1149. SUPPLEMENTARY INFORMATION: Comments Invited The FAA has determined that good cause exists for making these special conditions effective upon issuance; however, interested persons are invited to submit such written data, views, or arguments as they may desire. Communications should identify the [[Page 34717]] regulatory docket and special condition number and be submitted in duplicate to the address specified above. All communications received on or before the closing date for comments will be considered by the Administrator. These special conditions may be changed in light of the comments received. All comments submitted will be available in the Rules Docket for examination by interested persons, both before and after the closing date for comments. A report summarizing each substantive public contact with FAA personnel concerning this rulemaking will be filed in the docket. Persons wishing the FAA to acknowledge receipt of their comments submitted in response to this request must submit with those comments a self-addressed, stamped postcard on which the following statement is made: ``Comments to Docket No. NM-127.'' The postcard will be date stamped and returned to the commenter. Background On April 8, 1996, Columbia Avionics, 11200 Airport Road, Columbia, MO 65201, applied for a Supplemental Type Certificate (STC) to modify Cessna 500, 550, and S550 airplanes to incorporate the installation of an electronic flight instrument system (EFIS). The airplanes are pressurized, executive transport airplanes powered by two fuselage- mounted turbofan engines. Supplemental Type Certification Basis Under the provisions of Sec. 21.101 of 14 CFR part 21, Columbia Avionics must show that the modified Cessna 500, 550, and S550 airplanes continue to meet the applicable provisions of the regulations incorporated by reference in Type Certificate A22CE, or the applicable regulations in effect on the date of application for the change. The regulations incorporated by reference in the type certificate are commonly referred to as the ``original type certification basis.'' The regulations incorporated by reference in TC A22CE include the following for the Cessna 500, 550 and S550 series: 14 CFR part 25, dated February 1, 1965, as amended by Amendments 25-1 through 25-17, and Secs. 25.934 and 25.1091(d)(2), as amended through Amendment 25-23. In addition, under Sec. 21.101(b)(1), the following regulations apply to the EFIS installation: Secs. 25.1303, 25.1305, and 25.1322, as amended by Amendment 25-38; Secs. 25.1309, 25.1321 (a), (b), (d), and (e), 25.1331, 25.1333, and 25.1335, as amended by Amendment 25-41; and Sec. 25.1316, as amended by Amendment 25-80. These special conditions form an additional part of the type certification basis. If the Administrator finds that the applicable airworthiness regulations (i.e., part 25, as amended) do not contain adequate or appropriate safety standards for the Cessna Model 500, 550, and S550 series airplanes because of a novel or unusual design feature, special conditions are prescribed under the provisions of Sec. 21.16 to establish a level of safety equivalent to that established in the regulations. Special conditions, as appropriate, are issued in accordance with 14 CFR Sec. 11.49 after public notice, as required by Secs. 11.28 and 11.29(b), and become part of the type certification basis in accordance with Sec. 21.101(b)(2). Special conditions are initially applicable to the model for which they are issued. Should the applicant apply for a supplemental type certificate to modify any other model included on the same type certificate to incorporate the same novel or unusual design feature, the special conditions would also apply to the other model under the provisions of Sec. 21.101(a)(1). Novel or Unusual Design Features The Cessna Model 500, 550, and S550 airplanes incorporate new avionics/electronic systems, such as the electronic flight instrument system (EFIS), that perform critical functions. These systems may be vulnerable to high-intensity radiated fields (HIRF) external to the airplane. Discussion There is no specific regulation that addresses protection requirements for electrical and electronic systems from HIRF. Increased power levels from ground-based radio transmitters and the growing use of sensitive electrical and electronic systems to command and control airplanes have made it necessary to provide adequate protection. To ensure that a level of safety is achieved equivalent to that intended by the regulations incorporated by reference, a special condition is needed for the Cessna Model 500, 550, and S550, as modified by Columbia Avionics, which requires that new electrical and electronic systems, such as the EFIS, that perform critical functions be designed and installed to preclude component damage and interruption of function due to both the direct and indirect effects of HIRF. High-Intensity Radiated Fields (HIRF) With the trend toward increased power levels from ground-based transmitters, plus the advent of space and satellite communications, coupled with electronic command and control of the airplane, the immunity of critical digital avionics systems, such as the EFIS, to HIRF must be established. It is not possible to precisely define the HIRF to which the airplane will be exposed in service. There is also uncertainty concerning the effectiveness of airframe shielding for HIRF. Furthermore, coupling of electromagnetic energy to cockpit-installed equipment through the cockpit window apertures is undefined. Based on surveys and analysis of existing HIRF emitters, an adequate level of protection exists when compliance with the HIRF protection special condition is shown with either paragraphs 1 OR 2 below: 1. A minimum threat of 100 volts per meter peak electric field strength from 10 KHz to 18 GHz. a. The threat must be applied to the system elements and their associated wiring harnesses without the benefit of airframe shielding. b. Demonstration of this level of protection is established through system tests and analysis. 2. A threat external to the airframe of the following field strengths for the frequency ranges indicated. ------------------------------------------------------------------------ Peak (V/ Average Frequency M) (V/M) ------------------------------------------------------------------------ 10 KHz-100 KHz....................................... 50 50 100 KHz-500 KHz..................................... 60 60 500 KHz-2 MHz....................................... 70 70 2 MHz-30 MHz......................................... 200 200 30 MHz-100 MHz....................................... 30 30 100 MHz-200 MHz...................................... 150 33 200 MHz-400 MHz...................................... 70 70 400 MHz-700 MHz...................................... 4,020 935 700 MHz-1 GHz........................................ 1,700 170 1 GHz-2 GHz.......................................... 5,000 990 2 GHz-4 GHz.......................................... 6,680 840 4 GHz-6 GHz.......................................... 6,850 310 6 GHz-8 GHz.......................................... 3,600 670 8 GHz-12 GHz......................................... 3,500 1,270 12 GHz-18 GHz........................................ 3,500 360 18 GHz-40 GHz........................................ 2,100 750 ------------------------------------------------------------------------ As discussed above, these special conditions are applicable to the Cessna Model 500, 550, and S550 airplanes, as modified by Columbia Avionics, Inc. Should Columbia Avionics apply at a later date for a supplemental type certificate to modify any other model included on Type Certificate No. A22CE to incorporate the same novel or unusual design feature, this special condition would apply to that model as well, under the provisions of Sec. 21.101(a)(1). Conclusion This action affects only certain design features on the Cessna Model 500, 550, and S550 airplanes. It is not a rule of general applicability and affects only the applicant who applied to the FAA [[Page 34718]] for approval of these features on the airplane. The substance of the special conditions for this airplane has been subject to the notice and comment procedure in several prior instances and has been derived without substantive change from those previously issued. It is unlikely that prior public comment would result in a significant change from the substance contained herein. For this reason, and because a delay would significantly affect the certification of the airplane, which is imminent, the FAA has determined that prior public notice and comment are unnecessary and impracticable, and good cause exists for adopting these special conditions immediately. Therefore, these special conditions are being made effective upon issuance. The FAA is requesting comments to allow interested persons to submit views that may not have been submitted in response to the prior opportunities for comment described above. List of Subjects in 14 CFR Part 25 Aircraft, Aviation safety, Reporting and recordkeeping requirements. The authority citation for this special condition is as follows: Authority: 49 U.S.C. 106(g), 40113, 44701, 44702, 44704. The Special Conditions Accordingly, pursuant to the authority delegated to me by the Administrator, the following special conditions are issued as part of the type certification basis for Cessna Model 500, 550, and S550 airplanes, as modified by Columbia Avionics, Inc. 1. Protection from Unwanted Effects of High-Intensity Radiated Fields (HIRF). Each electrical and electronic system that performs critical functions must be designed and installed to ensure that the operation and operational capability of these systems to perform critical functions are not adversely affected when the airplane is exposed to high-intensity radiated fields. 2. For the purpose of this special condition, the following definition applies: Critical Functions. Functions whose failure would contribute to or cause a failure condition that would prevent the continued safe flight and landing of the airplane. Issued in Renton, Washington, in June 20, 1996. Gary L. Killion, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service, ANM-100. [FR Doc. 96-16959 Filed 7-2-96; 8:45 am] BILLING CODE 4910-13-M