[Federal Register Volume 69, Number 37 (Wednesday, February 25, 2004)]
[Rules and Regulations]
[Pages 8551-8555]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-4177]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 23

[Docket No. CE203, Special Condition 23-143-SC]


Special Conditions; Avidyne Corporation, Inc.; Various Airplane 
Models; Protection of Systems for High Intensity Radiated Fields (HIRF)

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions; request for comments.

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SUMMARY: These special conditions are issued to Avidyne Corporation, 55 
Old Bedford Road, Lincoln, MA 01773, for a Supplemental Type 
Certificate for the models listed under the heading ``Type 
Certification Basis.'' This special condition includes various airplane 
models to streamline the certification process needed to improve the 
safety of the airplane fleet by fostering the incorporation of new 
technologies that can be certificated affordably under 14 CFR part 23.
    The 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 an electronic flight instrument system 
(EFIS) display, Model 700-00006- 1XX(), manufactured by Avidyne 
Corporation, 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 February 11, 
2004. Comments must be received on or before March 26, 2004.

ADDRESSES: Comments may be mailed in duplicate to: Federal Aviation 
Administration, Regional Counsel, ACE-7, Attention: Rules Docket Clerk, 
Docket No. CE203, Room 506, 901 Locust, Kansas City, Missouri 64106. 
All comments must be marked: Docket No. CE203. 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: Wes Ryan, Aerospace Engineer, 
Standards Office (ACE-110), Small Airplane Directorate, Aircraft 
Certification Service, Federal Aviation Administration, 901 Locust, 
Room 301, Kansas City, Missouri 64106; telephone (816) 329-4127.

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 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. CE203.'' The postcard will be date stamped and 
returned to the commenter.

Background

    On July 3, 2003, Avidyne Corporation, 55 Old Bedford Road, Lincoln, 
MA 01773, made an application to the FAA for a new Supplemental Type 
Certificate for airplane models listed under the type certification 
basis. The models are currently approved under the type certification 
basis listed in the paragraph headed ``Type Certification Basis.'' 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, Avidyne 
Corporation must show that 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 Sec.  23.1301 of 
Amendment 23-20; Sec. Sec.  23.1309, 23.1311, and 23.1321 of Amendment

[[Page 8552]]

23-49; and Sec.  23.1322 of Amendment 23-43; exemptions, if any; and 
the special conditions adopted by this rulemaking action.

----------------------------------------------------------------------------------------------------------------
                                                               Type  Certificate
          Aircraft make                Aircraft model(s)              No.               Certification basis
----------------------------------------------------------------------------------------------------------------
Aerostar Aircraft Corporation....  PA-60-600, PA-60-601, PA-  A17WE                FAR 23
                                    60-601P, PA60-602P, PA-
                                    60-700P.
                                   360, 400.................  A11WE                FAR 23
American Champion................  7AC, 7ACA, S7AC, 7BCM,     A-759                CAR 3
                                    7CCM, S7CCM, 7DC, S7DC,
                                    7EC, S7EC, 7ECA, 7FC,
                                    7GC, 7GCA, 7GCB, 7GCBA,
                                    7GCBC, 7GCAA, 7HC, 7JC,
                                    7KC, 7KCAB.
                                   8GCBC, 8KCAB.............  A21CE                FAR 23
Cessna Aircraft Company..........  140A.....................  5A2                  CAR 3
                                   150, 150A, 150B, 150C,     3A19                 CAR 3
                                    150D, 150E, 150F, 150G,
                                    150H, 150J, 150K, A150K,
                                    150L, A150L, 150M,
                                    A150M, 152, A152.
Cessna Aircraft Company (cont'd).  170, 170A, 170B..........  A-799                CAR 3
                                   172, 172A, 172B, 172C,     3A12                 CAR 3, 14 CFR 23
                                    172D, 172E, 172F, 172G,
                                    172H, 172I, 172K, 172L,
                                    172M, 172N, 172P, 172Q,
                                    172R, 172S.
                                   172RG, P172D, R172E,       3A17                 CAR 3
                                    R172F, R172G, R172H,
                                    R172J, R172K, 175, 175A,
                                    175B, 175C.
                                   177, 177A, 177B, 177RG...  A13CE                14 CFR 23
                                   180, 180A, 180B, 180C,     5A6                  CAR 3
                                    180D, 180E, 180F, 180G,
                                    180H, 180J, 180K.
                                   182, 182A, 182B, 182C,     3A13                 CAR 3, 14 CFR 23
                                    182D, 182E, 182F, 182G,
                                    182H, 182J, 182K, 182L,
                                    182M, 182N, 182P, 182Q,
                                    182R, 182S, R182, T182,
                                    TR182.
                                   185, 185A, 185B, 185C,     3A24                 CAR 3
                                    185D, 185E, A185E, A185F.
                                   190, 195, 195A, 195B.....  A-790                CAR 3
                                   210, 210A, 210B, 210C,     3A21                 CAR 3
                                    210D, 210E, 210F, T210F,
                                    210G, T210G, 210H,
                                    T210H, 210J, T210J,
                                    210K, T210K, 210L,
                                    T210L, 210M, T210M,
                                    210N, P210N, T210N,
                                    210R, P210R, T210-R, 210-
                                    5, 210-5A.
                                   205, 206, P206, P206-A,    A4CE                 CAR 3, 14 CFR 23
                                    P206-B, P206-C, P206-D,
                                    P206-E, TP206-A, TP206-
                                    B, TP206-C, TP206-D,
                                    TP206-E, U206, U206-A,
                                    U206-B, U206-C, U206-D,
                                    U206-E, U206-F, U206-G,
                                    TU206A, TU206-B, TU206-
                                    C, TU206-D, TU206-E,
                                    TU206-F, TU206-G, 206H,
                                    T206H.
                                   207, 207A, T207, T207A...  A16CE                14 CFR 23
                                   208, 208A, 208B..........  A37CE                14 CFR 23
                                   310, 310A (USAF U-3A),     3A10                 CAR 3
                                    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, 320-1, 320A, 320B,    3A25                 CAR 3
                                    320C, 320D, 320E, 320F,
                                    340, 340A, 335, 340,
                                    340A.
                                   336......................  A2CE                 CAR 3
Cessna Aircraft Company (cont'd).  337 and 337A (USAF O2B),   A6CE                 CAR 3, 14 CFR 23
                                    337B, T337B, 337C,
                                    T337C, 337D, T337D,
                                    M337B (USAF O2A), 337E,
                                    T337E and T337F, 337F,
                                    T337G, 337G, 337H,
                                    T337H, P337H, T337H-SP.
                                   401, 401A, 401B, 402,      A7CE                 CAR 3
                                    402A, 402B, 402C, 411,
                                    411A, 414, 414A, 421,
                                    421A, 421B, 421C, 425.
                                   441......................  A28CE                FAR23
                                   404, 406.................  A25CE                FAR23
                                   500......................  A22CE                FAR23
                                   501, 551.................  A27CE                FAR23
                                   525, 525A................  A1WI                 FAR23
Cirrus Design Corp...............  SR20, SR22...............  A00009CH             FAR23
Commander Aircraft...............  112, 114, 112TC, 112B,     A12SO                CAR 3
                                    112TCA, 114A, 114B,
                                    114TC.
De Havilland Inc.................  DHC-2 Mk. I, DHC-2 Mk.     A-806                CAR 3
                                    II, DHC-2 Mk. III.
                                   (Twin Otter) DHC-6-1, DHC- A9EA                 CAR 3
                                    6-100, DHC-6-200, DHC-6-
                                    300.
Diamond Aircraft Industries......  DA 20-A1, DA20-C1........  TA4CH                14 CFR 23
                                   DA40.....................  A47CE                14 CFR 23
Fairchild........................  SA26-T, SA26-AT, SA226-T,  A5SW                 CAR 3
                                    SA226-AT, SA226-T(B),
                                    SA227-AT, SA227-TT.
                                   SA-226-TC, SA227-AC (C-    A8SW                 14 CFR 23
                                    26A), SA227-BC (C-26A),
                                    SA227-PC.
Lancair..........................  Columbia 300, LC40-550FG.  A00003SE             14 CFR 23
Learjet..........................  23.......................  A5CE                 CAR 3
Maule Aerospace Technology, Inc..  BEE DEE M-4, M-4, M-4C, M- 3A23                 CAR 3
                                    4S, and M-4T, M-4-210, M-
                                    4-210C, M-4-210S, and M-
                                    4-210T, M-4-220, M-4-
                                    220C, M-4-220S, and M-4-
                                    220T, M-4-180C, M-4-
                                    180S, and M-4-180T, M-5-
                                    210C, M-5-220C, M-5-
                                    235C, M-5-180C, M-5-
                                    210TC, M-6-235, M-6-180,
                                    M-5-200, 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, MXT-7-
                                    420, M-7-235B, M-7-235A,
                                    M-7-235C, MX-7-180C.
                                   M-7-260, M-7-420, M7-7-    3A23                 CAR3
                                    260, MT-7-420, M-7-260C.
Mitsubishi Heavy Industries, Ltd.  MU-2B-25, MU-2B-35, MU-2B- A10SW                CAR 3
                                    26, MU-2B-36, MU-2B-26A,
                                    MU-2B-36A, MU-28-40, MU-
                                    2B-60.

[[Page 8553]]

 
Mooney Aircraft Corp.............  M20, M20A, M20B, M20C,     2A3                  CAR 3
                                    M20D, M20E, M20F, M20G,
                                    M20J, M20K, M20L, M20M,
                                    M20R, M20S.
                                   M22......................  A6SW                 CAR 3
Partenavia Costruzioni             P 68, P 68B, P 68C, P 68C- A31EU                14 CFR 23
 Aeronauticas S.p.A.                TC, P 68 ``OBSERVER'',
                                    AP68 TP series 300
                                    ``SPARTACUS'', P68TC,
                                    ``OBSERVER'', AP68TP 600
                                    ``VIATOR'', P68
                                    ``OBSERVER 2''.
                                   VA300....................
The New Piper Aircraft, Inc......  PA-23, PA-23-160, PA-23-   1A10                 CAR 3
                                    235, PA-23-250, PA-E23-
                                    250.
                                   PA-28-140, PA-28-150, PA-  2A13                 CAR 3
                                    28-151, PA-28-160, PA-28-
                                    180, PA-28S-160, PA-28S-
                                    180, PA-28-235, PA-28-
                                    236, PA-28R-180, PA-28R-
                                    200, PA-28-181, PA-28-
                                    161, PA-28R-201, PA-28R-
                                    201T, PA-28RT-201, PA-
                                    28RT-201T, PA-28-201T.
                                   PA-30, PA-39, PA-40......  A1EA                 CAR 3
                                   PA-31, PA-31-300, PA-31-   A20SO                CAR 3
                                    325, PA-31-350.
                                   PA-31P, PA-31T, PA-31T1,   A8EA                 CAR 3
                                    PA-31T2, PA-31T3, PA-31P-
                                    350.
                                   PA-32-260, PA-32-300, PA-  A3SO                 CAR 3
                                    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-34-200, PA-34-200T, PA- A7SO                 CAR 3
                                    34-220T, PA-34-220T
                                    (III), PA-34-220T (IV).
                                   PA-42, PA-42-720, PA-42-   A23SO                FAR 23
                                    1000.
                                   PA-42-720R...............  A32SO                FAR 23
                                   PA-44-180, PA-44-180T....  A19SO                14 CFR 23
                                   PA-38-112................  A18SO                14 CFR 23
                                   PA-46-310P, PA-46-350P...  A25SO                14 CFR 23
Raytheon Aircraft Company........  H35, J35, K35, M35, 35-    3A15                 CAR 3
                                    33, N35, 35-A355, 35-
                                    B33, P35, S35, 35-C33,
                                    E33, F33, V35, V35A,
                                    V35B, 35-C33A, E33A,
                                    E33C, 36, A36, F33A,
                                    F33C, G33, A36TC, B36TC.
Raytheon Aircraft Company          95, B95, 95-55, 95-A55,    3A16                 CAR 3
 (cont'd).                          B95A, D95A, E95, 95-B55,
                                    95-B55A, 95-B55B, 95-
                                    C55, D55, 95-C55A, D55A,
                                    E55, E55A, 56TC, A56TC,
                                    58, 58A.
                                   58P, 58PA, 58TC, 58TCA...  A23CE                14 CFR 23
                                   F90......................  A31CE                FAR 23
                                   99, 99A, 99A (FACH), A99,  A14CE                FAR 23
                                    A99A, B99, C99, 100,
                                    A100 (U-21F), A100A,
                                    A100C, B100.
                                   200, A100-1 (U-21J),       A24CE                FAR 23
                                    200C, 200CT, 200T, A200
                                    (C-12A) or (C-12C),
                                    A200C (UC-12B), A200CT
                                    (C-12D) or (FWC-12D) or
                                    (RC-12D) or (C-12F) or
                                    (RC-12G), or (RC-12H) or
                                    (RC-12K) or (RC-12P) or
                                    (RC-12Q), B200, B200C (C-
                                    12F) or (UC-12F) or (UC-
                                    12M), or (C-12R),
                                    B200CT, B200T, 300,
                                    B300, B300C, 300LW,
                                    1900, 1900C (C-12J),
                                    1900D.
                                   65-90, 65-A90, B90, C90,   3A20                 CAR 3, FAR 23
                                    C90A.
Revo, Incorporated...............  Colonial C-1, Colonial C-  1A13                 CAR 3, 14 CFR 23
                                    2, Lake LA-4, LA-4A, LA-
                                    4P, Lake LA-4-200, Lake
                                    250.
Sky International................  Husky A-1, A-1A, A-1B....  A22NM                FAR 23
Socata Aerospatiale..............  TB 20, TB 10, TB 21, TB9,  A51EU                14 CFR 23
                                    TB 200.
                                   TBM 700..................  A60EU                14 CFR 23
Twin Commander Aircraft Corp.....  500, 500-A, 500-B, 500-U,  6A1                  CAR 23
                                    500-S, 520, 560, 560-A,
                                    560-E.
                                   560-F, 680, 680E, 680F,    2A4                  CAR 23
                                    720, 680FL, 680FL(P),
                                    680T, 680V, 680W, 681,
                                    685, 690, 690A, 690B,
                                    690C, 690D, 695, 695A,
                                    695B.
                                   700......................  A12SW                FAR 23
----------------------------------------------------------------------------------------------------------------

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) of Amendment 21-69.
    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

    Avidyne Corporation 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

[[Page 8554]]

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-GHz 6.....................................        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,
    (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 airplane models listed under the heading ``Type 
Certification Basis.'' Should Avidyne Corporation apply at a later date 
for a supplemental type certificate to modify any other model on the 
same type certificate to incorporate the same novel or unusual design 
feature, 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 
of one modification to several models of airplanes. 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 some airplane 
models, 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

0
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

0
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 airplane models listed under the 
``Type Certification Basis'' heading modified by Avidyne Corporation, 
to add an EFIS.
    1. Protection of Electrical and Electronic Systems from High 
Intensity Radiated Fields (HIRF). Each system

[[Page 8555]]

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 February 11, 2004.
James E. Jackson,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 04-4177 Filed 2-24-04; 8:45 am]
BILLING CODE 4910-13-P