[Federal Register Volume 68, Number 88 (Wednesday, May 7, 2003)]
[Rules and Regulations]
[Pages 24338-24340]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-11227]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM252, Special Conditions No. 25-235-SC]


Special Conditions: McDonnell Douglas Model DC-9-81, -82, -83, 
and -87 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 McDonnell Douglas 
Model DC-9-81, -82, -83, and -87 airplanes modified by Electronic Cable 
Specialists. These airplanes will have novel or unusual design features 
when compared to the state of technology envisioned in the 
airworthiness standards for transport category airplanes. The 
modification involves installation of electronic flight displays that 
perform critical functions. 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 established by the existing 
airworthiness standards.

DATES: The effective date of these special conditions is April 14, 
2003. Comments must be received on or before June 6, 2003.

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. NM252, 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. NM252.

FOR FURTHER INFORMATION CONTACT: Meghan Gordon, FAA, Standardization 
Branch, ANM-113, Transport Airplane Directorate, Aircraft Certification

[[Page 24339]]

Service, 1601 Lind Avenue SW., Renton, Washington, 98055-4056; 
telephone (425) 227-2138; facsimile (425) 227-1149.

SUPPLEMENTARY INFORMATION:

Comments Invited

    The FAA has determined that notice and opportunity for public 
comment in accordance with 14 CFR 11.38 are unnecessary, because the 
FAA has provided previous opportunities to comment on substantially 
identical special conditions and has fully considered and addressed all 
the substantive comments received. Based on a review of the comment 
history and the comment resolution, the FAA is satisfied that new 
comments are unlikely. The FAA, therefore, finds that good cause exists 
for making these special conditions effective upon issuance.
    However, 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 special 
conditions, 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 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 
these special conditions, based on the comments we receive.
    If you want the FAA to acknowledge receipt of your comments on 
these special conditions, 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 back to you.

Background

    On September 12, 2002, Electronic Cable Specialists applied for a 
supplemental type certificate (STC) to modify McDonnell Douglas Model 
DC-9-81, -82, -83, and -87 airplanes. These airplanes are currently 
approved under Type Certificate A6WE. The modification installs 
electronic flight displays in the cockpit. The existing Captain's and 
First Officer's electro-mechanical attitude indicators (ADIs) and 
horizontal situation indicators (HSIs) will be replaced by flat panel 
displays with associated cockpit display controllers. These avionics/
electronics and electrical 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, Amendment 21-69, effective 
September 16, 1991, Electronic Cable Specialists must show that 
McDonnell Douglas Model DC-9-81, -82, -83, and -87 airplanes, as 
modified, continue to meet the applicable provisions of the regulations 
incorporated by reference in Type Certificate A6WE or the applicable 
regulations in effect on the date of application for the change. 
Subsequent changes have been made to Sec.  21.101 as part of Amendment 
21-77, but those changes do not become effective until June 10, 2003.
    The regulations incorporated by reference in the type certificate 
are commonly referred to as the ``original type certification basis.'' 
The certification basis for the McDonnell Douglas Model DC-9-81, -82, -
83, and -87 airplanes includes 14 CFR part 25, effective February 1, 
1965, as amended by amendments 25-1 through 25-40, except for special 
conditions and exceptions noted in Type Certificate A6WE.
    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 McDonnell Douglas Model DC-9-81, -
82, -83, and -87 airplanes modified by Electronic Cable Specialists 
because of novel or unusual design features, special conditions are 
prescribed under the provisions of Sec.  21.16.
    Special conditions, as defined in Sec.  11.19, are issued in 
accordance with Sec.  11.38 and become part of the type certification 
basis in accordance with Sec.  21.101(b)(2), Amendment 21-69, effective 
September 16, 1991.
    Special conditions are initially applicable to the model for which 
they are issued. Should Electronic Cable Specialists apply later for a 
supplemental type certificate to modify any other model included on 
Type Certificate A6WE to incorporate the same novel or unusual design 
features, these special conditions would also apply to the other model 
under the provisions of Sec.  21.101(a)(1), Amendment 21-69, effective 
September 16, 1991.

Novel or Unusual Design Features

    The McDonnell Douglas Model DC-9-81, -81, -83, and -87 airplanes 
modified by Electronic Cable Specialists will incorporate new 
electronic flight displays that perform critical functions. This system 
may be vulnerable to high-intensity radiated fields (HIRF) external to 
the airplane. The current airworthiness standards of part 25 do not 
contain adequate or appropriate safety standards for the protection of 
this equipment from the adverse effects of HIRF. Accordingly, these 
systems are considered to be novel or unusual design features.

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 McDonnell Douglas Model DC-9-81, -82, -
83, and -87 airplanes modified by Electronic Cable Specialists. These 
special conditions require that new avionics/ electronic and electrical 
systems 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 (HIRF)

    With the trend toward increased power levels from ground-based 
transmitters and the advent of space and satellite communications, 
coupled with electronic command and control of airplanes, the immunity 
of critical avionic/ electronic and electrical systems to HIRF must be 
established.
    It is not possible to precisely define the HIRF to which the 
airplanes 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 in accordance with either paragraph 1 OR 2 below:

[[Page 24340]]

    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 
identified in the table below 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 
McDonnell Douglas Model DC-9-81, -82, -83, and -87 airplanes modified 
by Electronic Cable Specialists. Should Electronic Cable Specialists 
apply later for design change approval to modify any other model 
included on Type Certificate A6WE to incorporate the same novel or 
unusual design feature, these special conditions would apply to that 
model as well under the provisions of Sec.  21.101(a)(1), Amendment 21-
69, effective September 16, 1991.

Conclusion

    This action affects only certain novel or unusual design features 
on McDonnell Douglas Model DC-9-81, -82, -83, and -87 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 these airplanes.
    The FAA has determined that notice and opportunity for public 
comment are unnecessary, because the FAA has provided previous 
opportunities to comment on substantially identical special conditions 
and has fully considered and addressed all the substantive comments 
received. The FAA is satisfied that new comments are unlikely and 
finds, therefore, that good cause exists for making these special 
conditions effective upon issuance.

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 McDonnell Douglas Model 
DC-9-81, -82, -83, and -87 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 April 14, 2003.
Ali Bahrami
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 03-11227 Filed 5-6-03; 8:45 am]
BILLING CODE 4910-13-P