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Special Conditions; ASPEN Avionics Inc. Model EFD 1000; Electronic Flight Instrument System (EFIS); Protection of Systems for High Intensity Radiated Fields (HIRF)

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Start Preamble


Federal Aviation Administration (FAA), DOT.


Final special conditions; request for comments.


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.


The effective date of these special conditions is November 30, 2007. Comments must be received on or before January 9, 2008.


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.

Start Further Info


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.

End Further Info End Preamble Start Supplemental 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.


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, § 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 § 23.1301 of Amendment 23-20; §§ 23.1309, 23.1311, and 23.1321 of Amendment 23-49; and § 23.1322 of Amendment 23-43; exemptions, if any; and the special conditions adopted by this rulemaking action.

Aircraft makeAircraft model(s)Type certificate No.Certification basisClass 1 or 2
Aermacchi S.p.A (Siai Marchetti)S.205-18/F, S.205-18/R, S.205-20/F, S.205-20/R, S.205-22/R, S.208, S.208AA9EUFAR 231
F.260, F.260B, F.260C, F.260D, F.260E, F.260FA10EUCAR 31
Aero Commander (Dynac Aerospace Corp)10, 10A, 100, 100A, 100-1801A21CAR 31
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Aeronautica Macchi S.p.A (Macchi)AL 60, AL 60-B, AL 60-F5, AL 60-C5 AM-37A12 A19EUCAR 3 FAR 231 1
Aerostar Aircraft Corp. (Piper Aerostar)360, 400A11WEFAR 232
American Champion402 8KCAB, 8GCBCA3CE A21CECAR 3 FAR 232 1
Aviat (Sky International)A-1, A-1A, A-1B S-1S, S-1T, S-2, S-2A, S-2B, S-2C, S-2SA22NM A8SOFAR 23 FAR 231 1
Bellanca (Alexandria Aircraft LLC)14-19, 14-19-2, 14-19-3, 14-19-3A,17-30, 17-31, 17-31TC1A3CAR 31
17-30A, 17-31A, 17-31ATCA18CEFAR 231
Cessna120, 140A-768CAR 31
140A5A2CAR 31
150, 150A, 150B, 150C, 150D, 150E, 150F, 150G,150H, 150J, 150K, 150L, 150M, A150K, A150L, A150M, 152, A1523A19CAR 3, FAR 231
170, 170A, 170BA-799CAR 31
172, 172A, 172B, 172C, 172D, 172E, 172F, 172G,172H, 172I, 172K, 172L, 172M, 172N, 172P, 172Q,172R, 172S3A12CAR 3, FAR 231
172RG, P172D, R172E, R172F, R172G, R172H, R172J, R172K, 175, 175A, 175B, 175C3A17CAR 31
177, 177A, 177BA13CEFAR 231
177RGA20CEFAR 231
180, 180A,180B, 180C, 180D, 180E, 180F, 180G, 180H, 180J, 180K5A6CAR 31
182, 182A, 182B, 182C, 182D, 182E, 182F, 182G, 182H, 182J, 182K, 182L, 182M, 182N, 182P, 182Q, 182R, 182S, 182T, R182, T182, TR182, T182T3A13CAR 3, FAR 231
185, 185A, 185B, 185C, 185D, 185E, A185E, A185F3A24CAR 31
190, 195, 195A, 195BA-790CAR 31
210, 210A, 210B, 210C, 210D, 210E, 210F, T210F, 210G, T210G, 210H, T210H, 210J, T210J, 210K, T210K, 210L, T210L, 210M, T210M, 210N, P210N, T210N, 210R, P210R, T210R, 210-5, 210-5A3A21CAR 31
206, P206, P206A, 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, T206HA4CECAR 31
207, 207A, T207, T207AA16CEFAR 231
T-303 (Crusader)A34CEFAR 232
310, 310A (USAF U-3A), 310B, 310C, 310D, 310E (USAF U-3B), 310F, 310G, 310H, E310H, 310I, 310J, 310J-1, E310J, 310K, 310L, 310N, 310P, T310P, 310Q, T310Q, 310R, T310R3A102
320, 320A, 320B, 320C, 320D, 320E, 320F, 320-1, 335, 340, 340A3A25CAR 32
336A2CECAR 32
337, 337A , 337B, T337B, 337C, 337E, T337E, T337C, 337D, T337D, M337B, 337F, T337F, 337G, T337G, 337H, P337H, T337H, T337H-SPA6CECAR 3, FAR 232
Cirrus Design CorpSR20, SR22A00009CHFAR 231
Commander Aircraft Co112, 112TC, 112B, 112TCA, 114, 114A, 114B, 114TCA12SOCAR 31
Cub CraftersCC18-180, CC18-180AA00006SEFAR 231
DeHavilland/BombardierDHC-2 Mark I, DHC-2 Mark II, DHC-2 Mark IIIA-806CAR 31
DH.C1, 21, 22, 22AA44EUFAR 211
Diamond Aircraft CompanyDA 20-A1, DA20-C1 DA 40TA4CH A47CEFAR 23 FAR 231 1
Extra (Extra Flugzeugbau GmbH)EA300, EA300L, EA300S, EA300/200 EA-400A67EU A43CEFAR 23 FAR 231 1
Found Aircraft Development, IncFBA-2C, FBA-2C1 (Bush Hawk), FBA-2C2 (Bush Hawk XP)A7EACAR 3, FAR 231
Gulfstream American CorporationG44, G44A, SCAN Type 30A-734CAR 4a2
Grob-WerkeG115, G115A, G115B, G115C, G115C2, G115D, G115D2, G115EGA57EUFAR 231
G120AA49CEFAR 231
Grumman American (Tiger Aircraft LLC)AA-1, AA-1A, AA-1B, AA-1C AA-5, AA-5A, AA-5B, AG-5BA11EA A16EAFAR 23 FAR 231 1
Hawker Beechcraft35-33, 35-A33, 35-B33, 35-C33, 35-C33A, E33, E33A, E33C, F33, F33A, F33C, G33, H35, J35, K35, M35, N35, P35, S35, V35, V35A, V35B, 36, A36, A36TC, B36TC3A15CAR 31
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35, A35, B35, C35, D35, E35, F35, G35, 35RA-777CAR 31
76A29CEFAR 231
95, B95, B95A, D95A, E95, 95-55, 95-A55, 95-B55, 95-B55A, 95-B55B (T-42A), 95-C55, 95-C55A, D55, D55A, E55, E55A, 56TC, A56TC, 58, 58A3A16CAR 3, FAR 232
19A, B19, M19A, 23, A23, A23A, A23-19, A23-24, B23, C23, A24, A24R, B24R, C24RA1CECAR 31
50, B50, C50, D50, D50A, D50B, D50C, D50E, D50E-5990, E50, F50, G50, H50, J505A4CAR 32
45 (YT-34), A45 (T-34A) or (B-45), D45 (T-34B)5A3CAR 31
Helio (Alliance Aircraft Group, LLC)H-250, H-295, HT-295, H391, H391B, H-395, H-395A, H-700, H-8001A8CAR 31
HST-550, HST-550AA4EACAR 31
500A2EACAR 32
King's Engineering Fellowship (The)Model 44 4500-300, 4500-300 Series IIA2WI A17CEFAR 23 FAR 232 2
Lake/Revo (Global Amphibians LLC)Colonial C-1, Colonial C-2, Lake LA-4, Lake LA-4A, Lake LA-4P, Lake LA-4-200, Lake Model 2501A13CAR 31
Lancair (Columbia Aircraft)LC40-550FG, LC41-550FG, LC42-550FGA00003SEFAR 231
Liberty Aerospace IncorporatedXL-2A00008DEFAR 231
Lockheed Aircraft Corporation402-22A11CAR 32
Luscombe Aircraft Corporation11A, 11EA-804CAR 31
MauleBee Dee M-4, M-4, M-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-7-4203A23CAR 31
Mooney Aircraft CorpM20, M20A, M20B, M20C, M20D, M20E, M20F, M20G, M20J, M20K, M20L, M20M, M20R, M20S2A3CAR 31
Moravan (Moravan a.s.)ZLIN 562L ZLIN Z-242L, Z-143LA30EU A76EUFAR 23 FAR 231 1
Navion Aircraft Company, Ltd. (Navion)Navion, Navion A, Navion B, Navion D, Navion E, Navion F, Navion G, Navion HA-782CAR 31
OMF (Ostmeck. Flugzeugbau GmbH)OMF-100-160A46CEFAR 231
Partenavia (Vulcanair S.p.A.)P68, P68B, P68C, P68C-TC, P68 “Observer,” P68 “Observer 2,” P68 TC “Observer”, AP68TP 300 “Spartacus”, AP68TP 600 “Viator”, VA300A31EUFAR 232
Pilatus Aircraft LimitedPC-6, PC-6-H1, PC-6-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-H27A15CAR 31
PC-7A50EUFAR 231
Piper (New Piper)PA-12, PA-12S PA-18, PA-18S, PA-18-105, 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, PA19SA-780 1A2CAR 3 CAR 31 1
PA-20, PA-20S, PA-20-115, PA-20S-115, PA-20-135, PA-20S-1351A4CAR 31
PA-22, PA-22-108, PA-22-135, PA-22S-135, PA-22-150, PA-22S-150, PA-22-160, PA-22S-1601A6CAR 31
PA-23, PA-23-160, PA-23-235, PA-23-2501A10CAR 32
PA-24, PA-24-250 PA-24-260, PA-24-4001A15CAR 31
PA-28-140, PA-28-150, 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-28-2362A13CAR 31
PA-30, PA-39, PA-40A1EACAR 32
PA-32-260, PA-32-300, 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, PA32-301XTCA3SOCAR 31
PA-34-200, PA-34-200T, PA-34-220TA7SOCAR 32
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PA-44-180, PA-44-180TA19SOFAR 231
PA-46-310P, PA-46-350P, PA-46-500TPA25SOFAR 231
Prop-Jets, Inc200, 200A, 200B, 200C, 200D, 4003A18CAR 31
PZL (Panstwowe Zaklady Lotnicze)PZL-104 WILGA 80, PZL-104M WILGA 2000, PZL-WARSZAWA PZL-KOLIBER 150A, PZL-KOLIBER 160A,A55EU A69EUFAR 23 FAR 231 1
PZL (PZL Mielec)PZL M20 03 PZL M26 01A68EU A44CEFAR 23 FAR 232 1
Slingsby Aviation LtdT67M260, T67M260-T3AA73EUFAR 231
SOCATA (SOCATA Groupe Aerospatiale)TB9, TB10, TB20, TB21, TB200 100S, 150ST, 150T, 235E, 235C MS880B, MS885, MS894A, MS893A, MS892A-150, MS892E-150, MS893E, MS894EA51EU 7A14FAR 23 CAR 31 1
SOCATA (SOCATA Groupe Aerospatiale)GA-7 (Cougar)A17SOFAR 232
Stinson (Univair Aircraft Corporation)108, 108-1, 108-2, 108-3, 108-5A-767CAR 31
Twin Commander Aircraft Corporation500, 500-A, 500-B, 500-U, 500-S, 520, 560, 560-A, 560-EATC 542CAR 31
WACO Aircraft CompanyWACO YMFATC 542Aero 7A1
Zenair LtdCH2000TA5CHFAR 231


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 § 21.16.

Special conditions, as appropriate, as defined in § 11.19, are issued in accordance with § 11.38 after public notice and become part of the type certification basis in accordance with § 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 § 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:

FrequencyField strength (volts per meter)
10 kHz-100 kHz5050
100 kHz-500 kHz5050
500 kHz-2 MHz5050
2 MHz-30 MHz100100
30 MHz-70 MHz5050
70 MHz-100 MHz5050
100 MHz-200 MHz100100
200 MHz-400 MHz100100
400 MHz-700 MHz70050
700 MHz-1 GHz700100
1 GHz-2 GHz2000200
2 GHz-4 GHz3000200
4 GHz-6 GHz3000200
6 GHz-8 GHz1000200
8 GHz-12 GHz3000300
12 GHz-18 GHz2000200
18 GHz-40 GHz600200
The field strengths are expressed in terms of peak root-mean-square (rms) values.


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(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.


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 § 21.101.


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.

Start List of Subjects

List of Subjects in 14 CFR Part 23

End List of Subjects


The authority citation for these special conditions is as follows:

Start Authority

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.

End Authority

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.

Start Signature

Issued in Kansas City, Missouri on November 30, 2007.

Patrick R. Mullen,

Acting Manager, Small Airplane Directorate, Aircraft Certification Service.

End Signature End Supplemental Information

[FR Doc. E7-23835 Filed 12-7-07; 8:45 am]