[Federal Register Volume 59, Number 106 (Friday, June 3, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-13521]


[[Page Unknown]]

[Federal Register: June 3, 1994]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM-96; Special Conditions No. 25-ANM-85]

 

Special Conditions: Modified AMD/BA Falcon 50 Series Airplanes, 
High Intensity Radiated Fields (HIRF)

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final special conditions; request for comments.

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SUMMARY: These special conditions are issued for AMD/BA Falcon 50 
series airplanes modified by Duncan Aviation, Inc., of Lincoln, 
Nebraska. These airplanes are equipped with digital electronic flight 
instrument systems (EFIS) that perform critical functions. The 
applicable regulations do not contain adequate or appropriate safety 
standards for the protection of the EFIS from the effects of high-
intensity radiated fields (HIRF). These special conditions provide the 
additional safety standards that the Administrator considers necessary 
to ensure that the critical functions performed by these systems are 
maintained when the airplane is exposed to HIRF.

DATES: The effective date of these special conditions is May 24, 1994. 
Comments must be received on or before July 18, 1994.

ADDRESSES: Comments on these final special conditions; request for 
comments, may be mailed in duplicate to: Federal Aviation 
Administration, Office of the Assistant Chief Counsel, Attn.: Rules 
Docket (ANM-7), Docket No. NM-96, 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-96.'' 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:
Mark Quam, FAA, Standardization Branch, Transport Airplane Directorate, 
Aircraft Certification Service, 1601 Lind Avenue SW., Renton, 
Washington 98055-4056; telephone (206) 227-2145.

SUPPLEMENTARY INFORMATION: 

Comments Invited

    The FAA has determined that good cause exists for making these 
special conditions effective upon issuance; however, interested persons 
are invited to submit such written data, views, or arguments as they 
may desire. Communications should identify the regulatory docket and 
special conditions number and be submitted in duplicate to the address 
specified above. All communications received on or before the closing 
date for comments will be considered by the Administrator. These 
special conditions may be changed in light of the comments received. 
All comments submitted will be available in the Rules Docket for 
examination by interested persons, both before and after the closing 
date for comments. A report summarizing each substantive public contact 
with FAA personnel concerning this rulemaking will be filed in the 
docket. Persons wishing the FAA to acknowledge receipt of their 
comments submitted in response to this request must submit with those 
comments a self-addressed, stamped postcard on which the following 
statement is made: '`Comments to Docket No. NM-96.'' The postcard will 
be date stamped and returned to the commenter.

Background

    On April 15, 1994, Duncan Aviation, Inc., of Lincoln, Nebraska, 
applied for a supplemental type certificate to modify the AMD/BA Falcon 
50 series airplanes. The AMD/BA Falcon 50 is a business jet with three 
aft-mounted turbojet engines. The airplane can carry two pilots and 8 
to 19 passengers, depending on the exit and interior configuration, and 
is capable of operating to an altitude of 45,000 feet. The proposed 
modification incorporates the installation of digital avionics 
consisting of an electronic flight instrument system (EFIS) that is 
potentially vulnerable to high-intensity radiated fields (HIRF) 
external to the airplane.

Supplemental Type Certification Basis

    Under the provisions of Sec. 21.101 of the Federal Aviation 
Regulations (FAR), Duncan Aviation, Inc., must show that the altered 
AMD/BA Falcon 50 series airplanes continue to meet the applicable 
provisions of the regulations incorporated by reference in Type 
Certificate No. A46EU, or the applicable regulations in effect on the 
date of application for the change. The regulations incorporated by 
reference in the type certificate are commonly referred to as the 
``original type certification basis.''
    The regulations incorporated by reference in Type Certificate No. 
A46EU include the following for the AMD/BA Falcon 50 series: Sec. 21.29 
of part 21, and 14 CFR part 25, dated February 1, 1965, as amended by 
Amendments 25-1 through 25-34. In addition the following regulations 
apply to the EFIS installation: Secs. 25.1303(b) and 25.1322, as 
amended through Amendment 25-38; and Secs. 25.1309, 25.1321(a), (b), 
(d), and (e), 25.1331, 25.1333, and 25.1335, as amended by Amendment 
25-41. These special conditions will form an additional part of the 
supplemental type certification basis.
    If the Administrator finds that the applicable airworthiness 
regulations (i.e., part 25, as amended) do not contain adequate or 
appropriate safety standards for the AMD/BA Falcon 50 series airplanes 
because of a novel or unusual design feature, special conditions are 
prescribed under the provisions of Sec. 21.16 to establish a level of 
safety equivalent to that established in the regulations.
    Special conditions, as appropriate, are issued in accordance with 
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 applicant apply for a supplemental type 
certificate to modify any other model included on the same type 
certificate to incorporate the same novel or unusual design feature, 
the special conditions would also apply to the other model under the 
provisions of Sec. 21.101(a)(1).

Discussion

    There is no specific regulation that addresses protection 
requirements for electrical and electronic systems from high-intensity 
radiated fields (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, special 
conditions are needed for the modified AMD/BA Falcon 50 series 
airplanes that would require that the EFIS be designed and installed to 
preclude component damage and interruption of function due to the 
effects of HIRF.

High-Intensity Radiated Fields (HIRF)

    When the trend toward increased power levels from ground-based 
transmitters, plus the advent of space and satellite communications, 
coupled with electronic command and control of the airplane, the 
immunity of critical digital avionics systems, such as the EFIS, to 
HIRF must be established.
    It is not possible to precisely define the HIRF to which the 
airplane will be exposed in service. There is also uncertainty 
concerning the effectiveness of airframe shielding for HIRF. 
Furthermore, coupling to cockpit-installed equipment through the 
cockpit window apertures is undefined. Based on surveys and analysis of 
existing HIRF emitters, an adequate level of protection exists when 
compliance with the HIRF protection special condition is shown with 
either paragraphs 1 or 2 below:
    1. A minimum threat of 100 volts per meter peak electric field 
strength from 10 KHz to 18 GHz.
    a. The threat must be applied to the system elements and their 
associated wiring harnesses without the benefit of airframe shielding.
    b. Demonstration of this level of protection is established through 
system tests and analysis.
    2. A threat external to the airframe of the following field 
strengths for the frequency ranges indicated.

------------------------------------------------------------------------
                                                      Peak (V/   Average
                      Frequency                          M)       (V/M) 
------------------------------------------------------------------------
10 KHz-100 KHz......................................        50        50
100 KHz-500 KHz.....................................        60        60
500 KHz-2000 KHz....................................        70        70
2 MHz-30 MHz........................................       200       200
30 MHz-70 MHz.......................................        30        30
70 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-1000 MHz....................................     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
------------------------------------------------------------------------

    The envelope given in paragraph 2 above is a revision to the 
envelope used in previously issued special conditions in other 
certification projects. It is based on new data and SAE AE4R 
subcommittee recommendations. This revised envelope includes data from 
Western Europe and the U.S.
    As discussed above, these special conditions are applicable to the 
AMD/BA Falcon 50 series airplanes, modified by Duncan Aviation. Should 
Duncan Aviation apply at a later date for a supplemental type 
certificate to modify any other model included on Type Certificate No. 
A46EU 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(a)(1).

Conclusion

    This action affects only certain unusual or novel design features 
on the AMD/BA Falcon 50 series 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 the special conditions for these airplanes 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 from the substance contained herein. For 
this reason, and because a delay would significantly affect the 
certification of the airplane, which is imminent, the FAA has 
determined that prior public notice and comment are unnecessary and 
impracticable, and good cause exists for adopting these special 
conditions immediately. Therefore, these special conditions are being 
made effective upon issuance. The FAA is requesting comments to allow 
interested persons to submit views that may not have been submitted in 
response to the prior opportunities for comment described above.

List of Subjects in 14 CFR Part 25

    Aircraft, Aviation safety, Reporting and recordkeeping 
requirements.

    The authority citation for these special conditions is as follows:
    Authority: 49 U.S.C. app. 1344, 1348(c), 1352, 1354(a), 1355, 
1421 through 1431, 1502, 1651(b)(2), 42 U.S.C. 1857f-10, 4321 et 
seq.; E.O. 11514; and 49 U.S.C. 106(g).

The Special Conditions

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the following special conditions are issued as part of 
the supplemental type certification basis for the modified AMD/BA 
Falcon 50 series 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 external to the airplane.
    2. The following definition applies with respect to this special 
condition: Critical Function. 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 
May 24, 1994.

Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service, ANM-100.
[FR Doc. 94-13521 Filed 6-2-94; 8:45 am]
BILLING CODE 4910-13-M