[Federal Register Volume 72, Number 236 (Monday, December 10, 2007)] [Rules and Regulations] [Pages 69579-69583] From the Federal Register Online via the Government Publishing Office [www.gpo.gov] [FR Doc No: E7-23835] ----------------------------------------------------------------------- DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 23 [Docket No. CE278, Special Condition 23-218-SC] Special Conditions; ASPEN Avionics Inc. Model EFD 1000; Electronic Flight Instrument System (EFIS); Protection of Systems for High Intensity Radiated Fields (HIRF) AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final special conditions; request for comments. ----------------------------------------------------------------------- SUMMARY: These special conditions are issued to ASPEN Avionics Inc., for a Supplemental Type Certificate for the models listed under the heading ``Type Certification Basis'' under the Approved Model List Process. These airplanes will have novel and unusual design features when compared to the state of technology envisaged in the applicable airworthiness standards. These novel and unusual design features include the installation of electronic flight instrument system (EFIS) displays Model EFD 1000 manufactured by ASPEN Avionics Inc., for which the applicable regulations do not contain adequate or appropriate airworthiness 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 the airworthiness standards applicable to these airplanes. DATES: The effective date of these special conditions is November 30, 2007. Comments must be received on or before January 9, 2008. ADDRESSES: Comments may be mailed in duplicate to: Federal Aviation Administration, Regional Counsel, ACE-7, Attention: Rules Docket Clerk, Docket No. CE278, Room 506, 901 Locust, Kansas City, Missouri 64106. All comments must be marked: Docket No. CE278. Comments may be inspected in the Rules Docket weekdays, except Federal holidays, between 7:30 a.m. and 4 p.m. FOR FURTHER INFORMATION CONTACT: Jim Brady, Aerospace Engineer, Standards Office (ACE-111), Small Airplane Directorate, Aircraft Certification Service, Federal Aviation Administration, 901 Locust, Room 301, Kansas City, Missouri 64106; telephone (816) 329-4132. SUPPLEMENTARY INFORMATION: The FAA has determined that notice and opportunity for prior public comment hereon are impracticable because these procedures would significantly delay issuance of the approval design and thus delivery of the affected aircraft. In addition, the substance of these special conditions has been subject to the public comment process in several prior instances with no substantive comments received. The FAA, therefore, finds that good cause exists for making these special conditions effective upon issuance. Comments Invited Interested persons are invited to submit such written data, views, or arguments as they may desire. Communications should identify the regulatory docket or notice 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. The special conditions may be changed in light of the comments received. All comments received 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. Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this notice must include a self- addressed, stamped postcard on which the following statement is made: ``Comments to Docket No. 278.'' The postcard will be date stamped and returned to the commenter. Background On June 26, 2007, ASPEN Avionics Inc., made an application to the FAA for a new Supplemental Type Certificate under the Approved Model List Process for the project airplanes. The proposed modification incorporates a novel or unusual design feature, such as digital avionics consisting of an EFIS that is vulnerable to HIRF external to the airplane. Type Certification Basis Under the provisions of 14 CFR part 21, Sec. 21.101, ASPEN Avionics Inc., must show that the affected airplane models, as changed, continue to meet the applicable provisions, of the regulations incorporated by reference in Type Certificate Numbers listed below 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'' and can be found in the Type Certificate Numbers listed below. In addition, the type certification basis of airplane models that embody this modification will include section Sec. 23.1301 of Amendment 23-20; Sec. Sec. 23.1309, 23.1311, and 23.1321 of Amendment 23-49; and Sec. 23.1322 of Amendment 23-43; exemptions, if any; and the special conditions adopted by this rulemaking action. ---------------------------------------------------------------------------------------------------------------- Class 1 Aircraft make Aircraft model(s) Type certificate No. Certification basis or 2 ---------------------------------------------------------------------------------------------------------------- Aermacchi S.p.A (Siai S.205-18/F, S.205-18/ A9EU.................. FAR 23............... 1 Marchetti). R, S.205-20/F, S.205- 20/R, S.205-22/R, S.208, S.208A. F.260, F.260B, F.260C, A10EU................. CAR 3................ 1 F.260D, F.260E, F.260F. Aero Commander (Dynac 10, 10A, 100, 100A, 1A21.................. CAR 3................ 1 Aerospace Corp). 100-180. [[Page 69580]] Aeronautica Macchi S.p.A AL 60, AL 60-B, AL 60- 7A12.................. CAR 3................ 1 (Macchi). F5, AL 60-C5. A19EU................. FAR 23............... 1 AM-3.................. Aerostar Aircraft Corp. (Piper 360, 400.............. A11WE................. FAR 23............... 2 Aerostar). American Champion............. 402................... A3CE.................. CAR 3................ 2 8KCAB, 8GCBC.......... A21CE................. FAR 23............... 1 Aviat (Sky International)..... A-1, A-1A, A-1B....... A22NM................. FAR 23............... 1 S-1S, S-1T, S-2, S-2A, A8SO.................. FAR 23............... 1 S-2B, S-2C, S-2S. Bellanca (Alexandria Aircraft 14-19, 14-19-2, 14-19- 1A3................... CAR 3................ 1 LLC). 3, 14-19-3A,17-30, 17- 31, 17-31TC. 17-30A, 17-31A, 17- A18CE................. FAR 23............... 1 31ATC. Cessna........................ 120, 140.............. A-768................. CAR 3................ 1 140A.................. 5A2................... CAR 3................ 1 150, 150A, 150B, 150C, 3A19.................. CAR 3, FAR 23........ 1 150D, 150E, 150F, 150G,150H, 150J, 150K, 150L, 150M, A150K, A150L, A150M, 152, A152. 170, 170A, 170B....... A-799................. CAR 3................ 1 172, 172A, 172B, 172C, 3A12.................. CAR 3, FAR 23........ 1 172D, 172E, 172F, 172G,172H, 172I, 172K, 172L, 172M, 172N, 172P, 172Q,172R, 172S. 172RG, P172D, R172E, 3A17.................. CAR 3................ 1 R172F, R172G, R172H, R172J, R172K, 175, 175A, 175B, 175C. 177, 177A, 177B....... A13CE................. FAR 23............... 1 177RG................. A20CE................. FAR 23............... 1 180, 180A,180B, 180C, 5A6................... CAR 3................ 1 180D, 180E, 180F, 180G, 180H, 180J, 180K. 182, 182A, 182B, 182C, 3A13.................. CAR 3, FAR 23........ 1 182D, 182E, 182F, 182G, 182H, 182J, 182K, 182L, 182M, 182N, 182P, 182Q, 182R, 182S, 182T, R182, T182, TR182, T182T. 185, 185A, 185B, 185C, 3A24.................. CAR 3................ 1 185D, 185E, A185E, A185F. 190, 195, 195A, 195B.. A-790................. CAR 3................ 1 210, 210A, 210B, 210C, 3A21.................. CAR 3................ 1 210D, 210E, 210F, T210F, 210G, T210G, 210H, T210H, 210J, T210J, 210K, T210K, 210L, T210L, 210M, T210M, 210N, P210N, T210N, 210R, P210R, T210R, 210-5, 210-5A. 206, P206, P206A, A4CE.................. CAR 3................ 1 P206B, P206C, P206D, P206E, TP206A, TP206B, TP206C, TP206D, TP206E, U206, U206A, U206B, U206C, U206D, U206E, U206F, U206G, TU206A, TU206B, TU206C, TU206D, TU206E, TU206F, TU206G, 206H, T206H. 207, 207A, T207, T207A A16CE................. FAR 23............... 1 T-303 (Crusader)...... A34CE................. FAR 23............... 2 310, 310A (USAF U-3A), 3A10.................. ..................... 2 310B, 310C, 310D, 310E (USAF U-3B), 310F, 310G, 310H, E310H, 310I, 310J, 310J-1, E310J, 310K, 310L, 310N, 310P, T310P, 310Q, T310Q, 310R, T310R. 320, 320A, 320B, 320C, 3A25.................. CAR 3................ 2 320D, 320E, 320F, 320- 1, 335, 340, 340A. 336................... A2CE.................. CAR 3................ 2 337, 337A , 337B, A6CE.................. CAR 3, FAR 23........ 2 T337B, 337C, 337E, T337E, T337C, 337D, T337D, M337B, 337F, T337F, 337G, T337G, 337H, P337H, T337H, T337H-SP. Cirrus Design Corp............ SR20, SR22............ A00009CH.............. FAR 23............... 1 Commander Aircraft Co......... 112, 112TC, 112B, A12SO................. CAR 3................ 1 112TCA, 114, 114A, 114B, 114TC. Cub Crafters.................. CC18-180, CC18-180A... A00006SE.............. FAR 23............... 1 DeHavilland/Bombardier........ DHC-2 Mark I, DHC-2 A-806................. CAR 3................ 1 Mark II, DHC-2 Mark III. DH.C1, 21, 22, 22A.... A44EU................. FAR 21............... 1 Diamond Aircraft Company...... DA 20-A1, DA20-C1..... TA4CH................. FAR 23............... 1 DA 40................. A47CE................. FAR 23............... 1 Extra (Extra Flugzeugbau GmbH) EA300, EA300L, EA300S, A67EU................. FAR 23............... 1 EA300/200. A43CE................. FAR 23............... 1 EA-400................ Found Aircraft Development, FBA-2C, FBA-2C1 (Bush A7EA.................. CAR 3, FAR 23........ 1 Inc. Hawk), FBA-2C2 (Bush Hawk XP). Gulfstream American G44, G44A, SCAN Type A-734................. CAR 4a............... 2 Corporation. 30. Grob-Werke.................... G115, G115A, G115B, A57EU................. FAR 23............... 1 G115C, G115C2, G115D, G115D2, G115EG. G120A................. A49CE................. FAR 23............... 1 Grumman American (Tiger AA-1, AA-1A, AA-1B, AA- A11EA................. FAR 23............... 1 Aircraft LLC). 1C. A16EA................. FAR 23............... 1 AA-5, AA-5A, AA-5B, AG- 5B. Hawker Beechcraft............. 35-33, 35-A33, 35-B33, 3A15.................. CAR 3................ 1 35-C33, 35-C33A, E33, E33A, E33C, F33, F33A, F33C, G33, H35, J35, K35, M35, N35, P35, S35, V35, V35A, V35B, 36, A36, A36TC, B36TC. [[Page 69581]] 35, A35, B35, C35, A-777................. CAR 3................ 1 D35, E35, F35, G35, 35R. 76.................... A29CE................. FAR 23............... 1 95, B95, B95A, D95A, 3A16.................. CAR 3, FAR 23........ 2 E95, 95-55, 95-A55, 95-B55, 95-B55A, 95- B55B (T-42A), 95-C55, 95-C55A, D55, D55A, E55, E55A, 56TC, A56TC, 58, 58A. 19A, B19, M19A, 23, A1CE.................. CAR 3................ 1 A23, A23A, A23-19, A23-24, B23, C23, A24, A24R, B24R, C24R. 50, B50, C50, D50, 5A4................... CAR 3................ 2 D50A, D50B, D50C, D50E, D50E-5990, E50, F50, G50, H50, J50. 45 (YT-34), A45 (T- 5A3................... CAR 3................ 1 34A) or (B-45), D45 (T-34B). Helio (Alliance Aircraft H-250, H-295, HT-295, 1A8................... CAR 3................ 1 Group, LLC). H391, H391B, H-395, H- 395A, H-700, H-800. HST-550, HST-550A..... A4EA.................. CAR 3................ 1 500................... A2EA.................. CAR 3................ 2 King's Engineering Fellowship Model 44.............. A2WI.................. FAR 23............... 2 (The). 4500-300, 4500-300 A17CE................. FAR 23............... 2 Series II. Lake/Revo (Global Amphibians Colonial C-1, Colonial 1A13.................. CAR 3................ 1 LLC). C-2, Lake LA-4, Lake LA-4A, Lake LA-4P, Lake LA-4-200, Lake Model 250. Lancair (Columbia Aircraft)... LC40-550FG, LC41- A00003SE.............. FAR 23............... 1 550FG, LC42-550FG. Liberty Aerospace Incorporated XL-2.................. A00008DE.............. FAR 23............... 1 Lockheed Aircraft Corporation. 402-2................. 2A11.................. CAR 3................ 2 Luscombe Aircraft Corporation. 11A, 11E.............. A-804................. CAR 3................ 1 Maule......................... Bee Dee M-4, M-4, M- 3A23.................. CAR 3................ 1 4C, M-4S, M-4T, M-4- 180C, M-4-180S, M-4- 180T, M-4-210, M-4- 210C, M-4-210S, M-4- 210T, M-4-220, M-4- 220C, M-4-220S, M-4- 220T, M-5-180C, M-5- 200, M-5-210C, M-5- 210TC, M-5-220C, M-5- 235C, M-6-180, M-6- 235, M-7-235, MX-7- 235, MX-7-180, MX-7- 420, MXT-7-180, MT-7- 235, M-8-235, MX-7- 160, MXT-7-160, MX-7- 180A, MXT-7-180A, MX- 7-180B, M-7-235B, M-7- 235A, M-7-235C, MX-7- 180C, M-7-260, MT-7- 260, M-7-260C, M-7- 420AC, MX-7-160C, MX- 7-180AC, M-7-420A, MT- 7-420. Mooney Aircraft Corp.......... M20, M20A, M20B, M20C, 2A3................... CAR 3................ 1 M20D, M20E, M20F, M20G, M20J, M20K, M20L, M20M, M20R, M20S. M22................... A6SW.................. CAR 3................ 1 Moravan (Moravan a.s.)........ ZLIN 562L............. A30EU................. FAR 23............... 1 ZLIN Z-242L, Z-143L... A76EU................. FAR 23............... 1 Navion Aircraft Company, Ltd. Navion, Navion A, A-782................. CAR 3................ 1 (Navion). Navion B, Navion D, Navion E, Navion F, Navion G, Navion H. OMF (Ostmeck. Flugzeugbau OMF-100-160........... A46CE................. FAR 23............... 1 GmbH). Partenavia (Vulcanair S.p.A.). P68, P68B, P68C, P68C- A31EU................. FAR 23............... 2 TC, P68 ``Observer,'' P68 ``Observer 2,'' P68 TC ``Observer'', AP68TP 300 ``Spartacus'', AP68TP 600 ``Viator'', VA300. Pilatus Aircraft Limited...... PC-6, PC-6-H1, PC-6- 7A15.................. CAR 3................ 1 H2, PC-6/350, PC-6/ 350-H1, PC-6/350-H2, PC-6/A, PC-6/A-H1, PC- 6/A-H2, PC-6/B-H2, PC- 6/B1-H2, PC-6/B2-H2, PC-6/B2-H4, PC-6/C- H2, PC-6/C1-H2. PC-7.................. A50EU................. FAR 23............... 1 Piper (New Piper)............. PA-12, PA-12S......... A-780................. CAR 3................ 1 PA-18, PA-18S, PA-18- 1A2................... CAR 3................ 1 105, PA-18S-105, PA- 18A, PA-18-125, PA- 18S-125, PA-18AS-125, PA-18-135, PA-18A- 135, PA-18S-135, PA- 18AS-135, PA-18-150, PA-18A-150, PA-18S- 150, PA-18AS-150, PA- 19, PA19S. PA-20, PA-20S, PA-20- 1A4................... CAR 3................ 1 115, PA-20S-115, PA- 20-135, PA-20S-135. PA-22, PA-22-108, PA- 1A6................... CAR 3................ 1 22-135, PA-22S-135, PA-22-150, PA-22S- 150, PA-22-160, PA- 22S-160. PA-23, PA-23-160, PA- 1A10.................. CAR 3................ 2 23-235, PA-23-250. PA-24, PA-24-250 PA-24- 1A15.................. CAR 3................ 1 260, PA-24-400. PA-28-140, PA-28-150, 2A13.................. CAR 3................ 1 PA-28-151, PA-28-160, PA-28-161, PA-28-180, PA-28-235, PA-28S- 160, PA-28-161, PA-28- 181, PA-28-235, PA- 28S-160, PA-28R-201, PA-28R-201T, PA-28RT- 201, PA-28RT-201T, PA- 28-201T, PA-28-236. PA-30, PA-39, PA-40... A1EA.................. CAR 3................ 2 PA-32-260, PA-32-300, A3SO.................. CAR 3................ 1 PA-32S-300, PA-32R- 300, PA-32RT-300, PA- 32RT-300T, PA-32R- 301(SP), PA-32R- 301(HP), PA-32R-301T, PA-32-301, PA-32- 301T, PA-32-301FT, PA32-301XTC. PA-34-200, PA-34-200T, A7SO.................. CAR 3................ 2 PA-34-220T. [[Page 69582]] PA-44-180, PA-44-180T. A19SO................. FAR 23............... 1 PA-46-310P, PA-46- A25SO................. FAR 23............... 1 350P, PA-46-500TP. Prop-Jets, Inc................ 200, 200A, 200B, 200C, 3A18.................. CAR 3................ 1 200D, 400. PZL (Panstwowe Zaklady PZL-104 WILGA 80, PZL- A55EU................. FAR 23............... 1 Lotnicze). 104M WILGA 2000, PZL- A69EU................. FAR 23............... 1 WARSZAWA. PZL-KOLIBER 150A, PZL- KOLIBER 160A,. PZL (PZL Mielec).............. PZL M20 03............ A68EU................. FAR 23............... 2 PZL M26 01............ A44CE................. FAR 23............... 1 Slingsby Aviation Ltd......... T67M260, T67M260-T3A.. A73EU................. FAR 23............... 1 SOCATA (SOCATA Groupe TB9, TB10, TB20, TB21, A51EU................. FAR 23............... 1 Aerospatiale). TB200. 7A14.................. CAR 3................ 1 100S, 150ST, 150T, 235E, 235C MS880B, MS885, MS894A, MS893A, MS892A-150, MS892E-150, MS893E, MS894E. SOCATA (SOCATA Groupe GA-7 (Cougar)......... A17SO................. FAR 23............... 2 Aerospatiale). Stinson (Univair Aircraft 108, 108-1, 108-2, 108- A-767................. CAR 3................ 1 Corporation). 3, 108-5. Twin Commander Aircraft 500, 500-A, 500-B, 500- ATC 542............... CAR 3................ 1 Corporation. U, 500-S, 520, 560, 560-A, 560-E. WACO Aircraft Company......... WACO YMF.............. ATC 542............... Aero 7A.............. 1 Zenair Ltd.................... CH2000................ TA5CH................. FAR 23............... 1 ---------------------------------------------------------------------------------------------------------------- Discussion If the Administrator finds that the applicable airworthiness standards do not contain adequate or appropriate safety standards because of novel or unusual design features of an airplane, special conditions are prescribed under the provisions of Sec. 21.16. Special conditions, as appropriate, as defined in Sec. 11.19, are issued in accordance with Sec. 11.38 after public notice 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 already 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. Novel or Unusual Design Features ASPEN Avionics Inc., plans to incorporate certain novel and unusual design features into an airplane for which the airworthiness standards do not contain adequate or appropriate safety standards for protection from the effects of HIRF. These features include EFIS, which are susceptible to the HIRF environment, that were not envisaged by the existing regulations for this type of airplane. Protection of Systems from High Intensity Radiated Fields (HIRF): Recent advances in technology have given rise to the application in aircraft designs of advanced electrical and electronic systems that perform functions required for continued safe flight and landing. Due to the use of sensitive solid state advanced components in analog and digital electronics circuits, these advanced systems are readily responsive to the transient effects of induced electrical current and voltage caused by the HIRF. The HIRF can degrade electronic systems performance by damaging components or upsetting system functions. Furthermore, the HIRF environment has undergone a transformation that was not foreseen when the current requirements were developed. Higher energy levels are radiated from transmitters that are used for radar, radio, and television. Also, the number of transmitters has increased significantly. There is also uncertainty concerning the effectiveness of airframe shielding for HIRF. Furthermore, coupling to cockpit-installed equipment through the cockpit window apertures is undefined. The combined effect of the technological advances in airplane design and the changing environment has resulted in an increased level of vulnerability of electrical and electronic systems required for the continued safe flight and landing of the airplane. Effective measures against the effects of exposure to HIRF must be provided by the design and installation of these systems. The accepted maximum energy levels in which civilian airplane system installations must be capable of operating safely are based on surveys and analysis of existing radio frequency emitters. These special conditions require that the airplane be evaluated under these energy levels for the protection of the electronic system and its associated wiring harness. These external threat levels, which are lower than previous required values, are believed to represent the worst case to which an airplane would be exposed in the operating environment. These special conditions require qualification of systems that perform critical functions, as installed in aircraft, to the defined HIRF environment in paragraph 1 or, as an option to a fixed value using laboratory tests, in paragraph 2, as follows: (1) The applicant may demonstrate that the operation and operational capability of the installed electrical and electronic systems that perform critical functions are not adversely affected when the aircraft is exposed to the HIRF environment defined below: ------------------------------------------------------------------------ Field strength (volts per meter) Frequency ------------------- Peak Average ------------------------------------------------------------------------ 10 kHz-100 kHz...................................... 50 50 100 kHz-500 kHz..................................... 50 50 500 kHz-2 MHz....................................... 50 50 2 MHz-30 MHz........................................ 100 100 30 MHz-70 MHz....................................... 50 50 70 MHz-100 MHz...................................... 50 50 100 MHz-200 MHz..................................... 100 100 200 MHz-400 MHz..................................... 100 100 400 MHz-700 MHz..................................... 700 50 700 MHz-1 GHz....................................... 700 100 1 GHz-2 GHz......................................... 2000 200 2 GHz-4 GHz......................................... 3000 200 4 GHz-6 GHz......................................... 3000 200 6 GHz-8 GHz......................................... 1000 200 8 GHz-12 GHz........................................ 3000 300 12 GHz-18 GHz....................................... 2000 200 18 GHz-40 GHz....................................... 600 200 ------------------------------------------------------------------------ The field strengths are expressed in terms of peak root-mean-square (rms) values. or, [[Page 69583]] (2) The applicant may demonstrate by a system test and analysis that the electrical and electronic systems that perform critical functions can withstand a minimum threat of 100 volts per meter, electrical field strength, from 10 kHz to 18 GHz. When using this test to show compliance with the HIRF requirements, no credit is given for signal attenuation due to installation. A preliminary hazard analysis must be performed by the applicant, for approval by the FAA, to identify either electrical or electronic systems that perform critical functions. The term ``critical'' means those functions, whose failure would contribute to, or cause, a failure condition that would prevent the continued safe flight and landing of the airplane. The systems identified by the hazard analysis that perform critical functions are candidates for the application of HIRF requirements. A system may perform both critical and non-critical functions. Primary electronic flight display systems, and their associated components, perform critical functions such as attitude, altitude, and airspeed indication. The HIRF requirements apply only to critical functions. Compliance with HIRF requirements may be demonstrated by tests, analysis, models, similarity with existing systems, or any combination of these. Service experience alone is not acceptable since normal flight operations may not include an exposure to the HIRF environment. Reliance on a system with similar design features for redundancy as a means of protection against the effects of external HIRF is generally insufficient since all elements of a redundant system are likely to be exposed to the fields concurrently. Applicability As discussed above, these special conditions are applicable to one modification to the aircraft models listed under the heading ``Type Certification Basis.'' Should ASPEN Avionics Inc., apply at a later date to extend this modification to include additional airplane models, the special conditions would apply to that model as well under the provisions of Sec. 21.101. Conclusion This action affects only certain novel or unusual design features on one modification to the aircraft models listed under the heading ``Type Certification Basis.'' It is not a rule of general applicability and affects only the applicant who applied to the FAA for approval of these features on the airplane. The substance of these special conditions has been subjected to the notice and comment period 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 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 23 Aircraft, Aviation safety, Signs and symbols. Citation The authority citation for these special conditions is as follows: Authority: 49 U.S.C. 106(g), 40113 and 44701; 14 CFR 21.16 and 21.101; and 14 CFR 11.38 and 11.19. 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 the EFD 1000 EFIS manufactured by ASPEN Avionics Inc. 1. Protection of Electrical and Electronic Systems from High Intensity Radiated Fields (HIRF). Each system that performs critical functions must be designed and installed to ensure that the operations, and operational capabilities of these systems to perform critical functions, are not adversely affected when the airplane is exposed to high intensity radiated electromagnetic fields external to the airplane. 2. For the purpose of these special conditions, 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 Kansas City, Missouri on November 30, 2007. Patrick R. Mullen, Acting Manager, Small Airplane Directorate, Aircraft Certification Service. [FR Doc. E7-23835 Filed 12-7-07; 8:45 am] BILLING CODE 4910-13-P