[Federal Register Volume 67, Number 27 (Friday, February 8, 2002)]
[Rules and Regulations]
[Pages 5934-5936]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-3129]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM210, Special Conditions No. 25-196-SC]


Special Conditions: Boeing Model 747-100, -100B, -200B, -200C, -
200F, -300, SR, and SP Series Airplanes; 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 for Boeing Model 747-100, 
-100B, -200B, -200C, -200F, -300, SR, and SP series airplanes modified 
by Electronic Cable Specialists. These airplanes will have novel and 
unusual design features when compared to the state of technology 
envisioned in the airworthiness standards for transport category 
airplanes. The modification incorporates the installation of triple 
Honeywell Classic Navigator Systems. The applicable airworthiness 
regulations do not contain adequate or appropriate safety 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 that provided by the existing 
airworthiness standards.

DATES: The effective date of these special conditions is January 25, 
2002. Comments must be received on or before March 11, 2002.

ADDRESSES: Comments on these special conditions may be mailed in 
duplicate to: Federal Aviation Administration, Transport Airplane 
Directorate, Attn: Rules Docket (ANM-113), Docket No. NM210, 1601 Lind 
Avenue SW., Renton, Washington, 98055-4056; or delivered in duplicate 
to the Transport Airplane Directorate at the above address. All 
comments must be marked: Docket No. NM210. 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: Meghan Gordon, FAA, Standardization 
Branch, ANM-113, Transport Airplane Directorate, Aircraft Certification 
Service, 1601 Lind Avenue SW., Renton, Washington, 98055-4056; 
telephone (425) 227-2138; facsimile (425) 227-1149.

SUPPLEMENTARY INFORMATION:

[[Page 5935]]

Comments Invited

    The FAA invites interested persons to participate in this 
rulemaking by submitting written comments, data, or views. The most 
helpful comments reference a specific portion of the proposal, explain 
the reason for any recommended change, and include supporting data. We 
ask that you send us two copies of written comments.
    We will file in the docket all comments we receive, as well as a 
report summarizing each substantive public contact with FAA personnel 
concerning these proposed special conditions. The docket is available 
for public inspection before and after the comment closing date. If you 
wish to review the docket in person, go to the address in the ADDRESSES 
section of this preamble between 7:30 a.m. and 4 p.m., Monday through 
Friday, except Federal holidays.
    We will consider all comments we receive on or before the closing 
date for comments. We will consider comments filed late if it is 
possible to do so without incurring expense or delay. We may change 
this proposal for special conditions in light of the comments we 
receive.
    If you want the FAA to acknowledge receipt of your comments on this 
proposal, include with your comments a pre-addressed, stamped postcard 
on which the docket number appears. We will stamp the date on the 
postcard and mail it to you.

Background

    On September 18, 2001, Electronic Cable Specialists, 5300 West 
Franklin Drive, Franklin, WI 53132, applied for a supplemental type 
certificate (STC) to modify Boeing Model 747-100, -100B, -200B, -200C, 
-200F, -300, SR, and SP series airplanes approved under Type 
Certificate No. A20WE. The 747 series airplanes are 231 feet, 10.2 
inches long and have a wing span of 195 feet, 8 inches. The height at 
vertical stabilizer to ground is 63 feet, 5 inches. The passenger load 
is 366 to 496 passengers, and the range is from 6,100 to 7,700 statute 
miles. The modification incorporates the installation of triple 
Honeywell Classic Navigator Systems. Each system consists of a 
Honeywell HT9100 Navigation Management System, an Inertial Reference 
Unit, and a Digital to Analog Adapter. These advanced systems use 
electronics to a far greater extent than the original Inertial 
Navigation Systems and may be more susceptible to electrical and 
magnetic interference caused by high-intensity radiated fields (HIRF). 
This disruption of signals could result in loss of attitude or present 
misleading information to the pilot.

Type Certification Basis

    Under the provisions of 14 CFR 21.101, Electronic Cable Specialists 
must show that the Boeing Model 747-100, -100B, -200B, -200C, -200F, -
300, SR, and SP series airplanes, as changed, continue to meet the 
applicable provisions of the regulations incorporated by reference in 
Type Certificate No. A20WE, 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 certification basis for the 
modified Boeing Model 747-100, -100B, -200B, -200C, -200F, -300, SR, 
and SP series airplanes includes 14 CFR part 25, dated February 1, 
1965, as amended by amendments 25-1 through 25-77, except for special 
conditions and exceptions noted in Type Certificate Data Sheet (TCDS) 
A20WE.
    If the Administrator finds that the applicable airworthiness 
regulations (that is, 14 CFR part 25, as amended) do not contain 
adequate or appropriate safety standards for the Boeing Model 747-100, 
-100B, -200B, -200C, -200F, -300, SR, and SP series airplanes because 
of novel or unusual design features, special conditions are prescribed 
under the provisions of 14 CFR 21.16.
    In addition to the applicable airworthiness regulations and special 
conditions, the Boeing Model 747-100, -100B, -200B, -200C, -200F, -300, 
SR, and SP series airplanes must comply with the fuel vent and exhaust 
emission requirement of 14 CFR part 34 and the noise certification 
requirement of part 36.
    Special conditions, as defined in 14 CFR 11.19, are issued in 
accordance with Sec. 11.38, and become part of the type certification 
basis in accordance with 14 CFR 21.101(b)(2).
    Special conditions are initially applicable to the model for which 
they are issued. Should Electronic Cable Specialists apply at a later 
date 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 features, these special conditions would also 
apply to the other model under the provisions of 14 CFR 21.101(a)(1).

Novel or Unusual Design Features

    The Boeing Model 747-100, -100B, -200B, -200C, -200F, -300, SR, and 
SP series airplanes will incorporate triple Honeywell Classic Navigator 
Systems, which perform critical functions. Each system consists of a 
Honeywell HT9100 Navigation Management System, an Inertial Reference 
Unit, and a Digital to Analog Adapter. Because these advanced systems 
use electronics to a far greater extent than the original Inertial 
Navigation Systems, they may be more susceptible to electrical and 
magnetic interference caused by high-intensity radiated fields (HIRF) 
external to the airplane. The current airworthiness standards (14 CFR 
part 25) do not contain adequate or appropriate safety standards that 
address protecting this equipment from the adverse effects of HIRF. 
Accordingly, these instruments are considered to be a novel or unusual 
design feature.

Discussion

    There is no specific regulation that addresses protection 
requirements for electrical and electronic systems from HIRF. Increased 
power levels from ground-based radio transmitters and the growing use 
of sensitive avionics/electronics and electrical 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 Boeing Model 747-100, -100B, -200B, -
200C, -200F, -300, SR, and SP series airplanes modified to include the 
new navigation system. These special conditions will require that the 
new Honeywell Classic Navigator Systems, which perform critical 
functions, be designed and installed to preclude component damage and 
interruption of function due to both the direct and indirect effects of 
HIRF.

High-Intensity Radiated Fields (HIRF)

    With the trend toward increased power levels from ground-based 
transmitters, plus the advent of space and satellite communications, 
coupled with electronic command and control of the airplane, the 
immunity of critical digital avionic/electronics and electrical systems 
to HIRF must be established.
    It is not possible to precisely define the HIRF to which the 
airplane will be exposed in service. There is also uncertainty 
concerning the effectiveness of airframe shielding for HIRF. 
Furthermore, coupling of electromagnetic energy to cockpit-installed 
equipment through the cockpit window apertures is undefined. Based on 
surveys and analysis of existing HIRF emitters, an adequate level of 
protection

[[Page 5936]]

exists when compliance with the HIRF protection special condition is 
shown in accordance with either paragraph 1 OR 2 below:
    1. A minimum threat of 100 volts rms (root-mean-square) per meter 
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 field strengths 
indicated in Table 1 for the frequency ranges indicated. Both peak and 
average field strength components from Table 1 are to be demonstrated.

                                 Table 1
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                                                       Field strength
                                                      (volts per meter)
                     Frequency                     ---------------------
                                                       Peak     Average
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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
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The field strengths are expressed in terms of peak of the root-mean-
  square (rms) over the complete modulation period.

    The threat levels identified above are the result of an FAA review 
of existing studies on the subject of HIRF, in light of the ongoing 
work of the Electromagnetic Effects Harmonization Working Group of the 
Aviation Rulemaking Advisory Committee.

Applicability

    As discussed above, these special conditions are applicable to 
Boeing Model 747-100, -100B, -200B, -200C, -200F, -300, SR, and SP 
series airplanes modified by Electronic Cable Specialists to include 
the Honeywell Classic Navigator Systems. Should Electronic Cable 
Specialists apply at a later date for a supplemental type certificate 
to modify any other model already included on Type Certificate A20WE to 
incorporate the same novel or unusual design features, these special 
conditions would apply to that model as well under the provisions of 14 
CFR 21.101(a)(1).

Conclusion

    This action affects only certain design features on Boeing Model 
747-100, -100B, -200B, -200C, -200F, -300, SR, and SP series airplanes 
modified by Electronic Cable Specialists. 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 this airplane has been 
subjected to the notice and comment procedure in several prior 
instances and has been derived without substantive change from those 
previously issued. 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 25

    Aircraft, Aviation safety, Reporting and recordkeeping 
requirements.

    The authority citation for these special conditions is as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701, 44702, 44704.

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 Boeing Model 747-100, -
100B, -200B, -200C, -200F, -300, SR, and SP series airplanes modified 
by Electronic Cable Specialists.
    1. Protection from Unwanted Effects of High-Intensity Radiated 
Fields (HIRF). Each electrical and electronic system that performs 
critical functions must be designed and installed to ensure that the 
operation and operational capability of these systems to perform 
critical functions are not adversely affected when the airplane is 
exposed to high-intensity radiated fields.
    2. For the purpose of 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 Renton, Washington, on January 25, 2002.
Ali Bahrami,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 02-3129 Filed 2-7-02; 8:45 am]
BILLING CODE 4910-13-P