[Federal Register Volume 60, Number 157 (Tuesday, August 15, 1995)] [Rules and Regulations] [Pages 42029-42031] From the Federal Register Online via the Government Publishing Office [www.gpo.gov] [FR Doc No: 95-20151] ======================================================================= ----------------------------------------------------------------------- DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 25 [Docket No. NM-116; Special Condition No. 25-ANM-104] Special Condition: Israel Aircraft Industries (IAI), Model Astra SPX, High-Intensity Radiated Fields AGENCY: Federal Aviation Administration, DOT. ACTION: Final special condition; request for comments. ----------------------------------------------------------------------- SUMMARY: This special condition is issued for the Israel Aircraft Industries (IAI) Model Astra SPX airplane. This new airplane utilizes new avionics/electronic systems, such as electronic displays and electronic engine controls, that 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). This special condition contains 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 this special condition is July 26, 1995. Comments must be received on or before September 14, 1995 ADDRESSES: Comments on this special condition may be mailed in duplicate to: Federal Aviation Administration, Office of the Assistant Chief Counsel, Attn: Rules Docket (ANM-7), Docket No. NM-116, 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-116. 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: Timothy Dulin, FAA, Standardization Branch, ANM-113, Transport Airplane Directorate, Aircraft Certification Service, 1601 Lind Avenue SW., Renton, Washington, 98055-4506; telephone (206) 227-2141. SUPPLEMENTARY INFORMATION: Comments Invited The FAA has determined that good cause exists for making this special condition effective upon issuance; however, interested persons are invited to submit such written data, views, or arguments as they may desire. Communications should identify the 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. This special condition 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 [[Page 42030]] 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-116.'' The postcard will be date stamped and returned to the commenter. Background On February 15, 1994, Israel Aircraft Industries (IAI), Ben Gurion International Airport, Tel Aviv 70100, Israel, applied for an amendment to Type Certificate (TC) A16NM to incorporate the Model Astra SPX airplane. The Astra SPX is a derivative of the Model 1125 Westwind Astra. The changes include installation of new Allied Signal (Garrett) TFE731-40/40A engines, which are a derivative of the existing TFE731- 3A-200G engines; installation of winglets and minor structural modifications to the wing; and installation of new avionics. Type Certification Basis Under the provisions of Sec. 21.101 of 14 CFR part 21, IAI must show that the Model Astra SPX meets the applicable regulations incorporated by reference in TC A16NM, 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 incorporate by reference in TC A16NM are as follows: Part 25, effective February 1, 1965, as amended by Amendments 25-1 through 25-54. The regulations in effect on the date of application include the applicable provisions of part 25 effective February 1, 1965, as amended by Amendments 25-1 through 25-79. In addition, the certification basis for the Model Astra SPX includes part 34, effective September 10, 1990, plus any amendments in effect at the time of certification; and part 36, effective December 1, 1969, as amended by Amendment 36-1 through the amendment in effect at the time of certification. This special condition will form an additional part of the type certification basis. In addition, the certification basis may include exemptions and other special conditions that are not relevant to this special condition. If the Administrator finds that the applicable airworthiness regulation (i.e., part 25, as amended) do not contain adequate or appropriate safety standards for the Astra SPX 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 Sec. 11.49 of the FAR after public notice, as required by Secs. 11.28 and 11.29, 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 type certificate for that model be amended later to include any other model that incorporates the same novel or unusual design feature, or should any other model already included on the same type certificate be modified 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 Model Astra SPX incorporates new avionic/electronic systems, such as electronic displays and electronic engine controls, that perform critical functions. These systems may be vulnerable to 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 IAI Astra SPX, which would require that new electrical and electronic systems 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 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. ------------------------------------------------------------------------ Average(V/ Frequency Peak(V/M) 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, this special condition would be applicable initially to the IAI Model Astra SPX. Should IAI apply at a later date for a change to the type certificate to include another model incorporating 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 IAI Astra SPX airplane. It is not a rule of general applicability and affects only the manufacturer who applied to the FAA for approval of these features on the airplane. The substance of the special condition for this airplane has been subjected 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 [[Page 42031]] 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 this special condition immediately. Therefore, this special condition is 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. app. 1344, 1354(a), 1355, 1421, 1423, 1424, 1425, 1428, 1429, 1430, and 49 U.S.C. 106(g). The Special Condition Accordingly, pursuant to the authority delegated to me by the Administrator, the following special condition is issued as part of the type certification basis for the Israel Aircraft Industries (IAI) Model Astra SPX airplanes. 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, on July 26, 1995. Darrell M. Pederson, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 95-20151 Filed 8-14-95; 8:45 am] BILLING CODE 4910-13-M