[Federal Register Volume 65, Number 85 (Tuesday, May 2, 2000)]
[Rules and Regulations]
[Pages 25435-25437]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-10912]



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Rules and Regulations
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Federal Register / Vol. 65, No. 85 / Tuesday, May 2, 2000 / Rules and 
Regulations

[[Page 25435]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM172, Notice No. 25-161-SC]


Special Conditions: Boeing Model 747-200 (E-4B) Series Airplanes; 
High Intensity Radiated Fields (HIRF)

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions; request for comments.

-----------------------------------------------------------------------

SUMMARY: These special conditions are issued for Boeing Model 747-200 
(E-4B) airplanes. These airplanes, modified by S.I.P. Technical 
Services, Inc., 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 a new Flight Management System (FMS) 
and an Electronic Flight Instrumentation System (EFIS). The applicable 
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 provide the additional 
safety standards that the Administrator considers necessary to ensure 
that the critical functions that this system performs are maintained 
when the airplane is exposed to HIRF.

DATES: The effective date of these special conditions is April 24, 
2000. Comments must be received on or before June 16, 2000.

ADDRESSES: Comments on these special conditions may be mailed in 
duplicate to: Federal Aviation Administration, Transport Airplane 
Directorate, Attention: Rules Docket (ANM-114), Docket No. NM172, 1601 
Lind Avenue SW., Renton, Washington, 98055-4056; or delivered in 
duplicate to the Transport Airplane Directorate at the above address. 
Comments must be marked: Docket No. NM172. Comments may be inspected in 
the Rules Docket weekdays, except Federal holidays, between 7:30 a.m. 
and 4:00 p.m.

FOR FURTHER INFORMATION CONTACT: Ross Landes, FAA, Transport Airplane 
Directorate, Aircraft Certification Service, Standardization Branch, 
ANM-113, 1601 Lind Avenue SW., Renton, Washington, 98055-4056; 
telephone (425) 227-1071; facsimile (425) 227-1149.

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 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 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. Persons wishing 
the FAA to acknowledge receipt of their comments submitted in response 
to these special conditions must include with those comments a self-
addressed, stamped postcard on which the following statement is made: 
``Comments to Docket No. NM172.'' The postcard will be date stamped and 
returned to the commenter.

Background

    On November 10, 1998, S.I.P. Technical Services, Inc., 10107 
McAllister Freeway, San Antonio, Texas 78216-4648, applied for a 
supplemental type certificate (STC) to modify Boeing Model 747-200 (E-
4B) airplanes listed on Type Certificate A20WE. The modification 
incorporates the installation of a new Flight Management System (FMS) 
and an Electronic Flight Instrumentation System (EFIS). The new FMS 
consists of three Flight Management Computers (FMC) and three Multi-
Purpose Control Display Units (MCDU). The new EFIS consists of Active 
Matrix Liquid Crystal Display (AMLCD) Electronic Flight Instrument 
(EFI) units with embedded symbol generators and new control panels. The 
installation of these systems may be vulnerable to high-intensity 
radiated fields (HIRF) external to the airplane.

Type Certification Basis

    Under the provisions of 14 CFR 21.101, S.I.P. Technical Services, 
Inc. must show that Boeing Model 747-200 (E-4B) 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 regulations incorporated by reference in 
Type Certificate No. A20WE are as follows:
    The certification basis for the modified Boeing Model 747-200 (E-
4B) airplanes include title 14 Code of Federal Regulations (14 CFR), 
part 25, effective February 1, 1965, as amended by Amendments 25-1 
through 25-8, plus Amendments 25-15, 25-17, 25-18, 25-20, and 25-39.
    In addition to the applicable airworthiness regulations and special 
conditions, the Model 747-200 (E-4B) must comply with the part 25 fuel 
vent and exhaust emission requirements of 14 CFR part 34 and the part 
25 noise certification requirements of 14 CFR part 36.
    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 Boeing Model 747-200 (E-4B) 
airplanes because of a novel or unusual design feature, special 
conditions are prescribed under the provisions of Sec. 21.16.
    Special conditions, as appropriate, are issued in accordance with 
Sec. 11.49, as required by Secs. 11.28 and 11.29(b), 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 S.I.P. Technical Services, Inc. apply for a 
supplemental

[[Page 25436]]

type certificate to modify any other model included on the same type 
certificate to incorporate the same novel or unusual design features, 
the special conditions would also apply to the other model under the 
provisions of Sec. 21.101(a)(1).

Novel or Unusual Design Features

    The modified Boeing Model 747-200 (E-4B) airplanes will incorporate 
the following new design features: the installation of new Flight 
Management System (FMS) and Electronic Flight Instrumentation System 
(EFIS). The new FMS consists of three Flight Management Computers (FMC) 
and three Multi-purpose Control Display Units (MCDU). The new EFIS 
consists of Active Matrix Liquid Crystal Display (AMLCD) Electronic 
Flight Instrument (EFI) units with embedded symbol generators and new 
control panels. The installation of these systems may be vulnerable to 
HIRF external to the airplane.

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 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 Boeing Model 747-200 (E-4B) airplanes. 
These special conditions require that new electrical and electronic 
systems, such as the FMS and EFIS that 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

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

------------------------------------------------------------------------
                                                       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 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 the 
Boeing Model 747-200 (E-4B) airplanes modified by S.I.P. Technical 
Services, Inc. Should S.I.P. Technical Services, Inc. apply at a later 
date for a supplemental type certificate to modify any other model 
included on the same type certificate to incorporate the same novel or 
unusual design features, these special conditions would apply to that 
model as well under the provisions of Sec. 21.101(a)(1).

Conclusion

    This action affects only certain novel or unusual design features 
on Boeing Model 747-200 (E-4B) airplanes modified by S.I.P. Technical 
Services, Inc. It is not a rule of general applicability, and it 
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. 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 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 type certification basis for Boeing Model 747-200 (E-4B) airplanes 
modified by S.I.P. Technical Services, Inc.
    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.


[[Page 25437]]


    Issued in Renton, Washington, on April 24, 2000.
Vi L. Lipski,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-10912 Filed 5-1-00; 8:45 am]
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