[Federal Register Volume 64, Number 169 (Wednesday, September 1, 1999)]
[Rules and Regulations]
[Pages 47649-47651]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-22751]



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  Federal Register / Vol. 64, No. 169 / Wednesday, September 1, 1999 / 
Rules and Regulations  

[[Page 47649]]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM-163; Special Conditions No. 25-147-SC]


Special Conditions: Rockwell Collins; Boeing Model 737-300/-400/-
500 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 737-300/-
400/-500 series airplanes modified by Rockwell Collins. These modified 
airplanes will have a novel or unusual design feature associated with 
the Rockwell Collins Multi-Mode Receiver (MMR) System. The applicable 
airworthiness regulations do not contain adequate or appropriate safety 
standards for this design feature. 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 August 23, 
1999. Comments must be received on or before October 1, 1999.

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. NM-163, 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. NM-163. 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: Mark Quam, FAA, Standardization 
Branch, ANM-113, Transport Airplane Directorate, Aircraft Certification 
Service, 1601 Lind Avenue SW., Renton, Washington 98055-4056; telephone 
(425) 227-2145; facsimile (425) 227-1149.

SUPPLEMENTARY INFORMATION:

FAA's Determination as to Need for Public Process

    The FAA has determined that notice and opportunity for prior public 
comment hereon are impracticable because those procedures would 
significantly delay issuance of the approval design and, thus, the 
delivery of the affected aircraft. (The aircraft are scheduled for 
delivery in mid-September 1999.)
    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. Thus, the FAA has previously provided 
the public with a number of opportunities to comment on proposed 
special conditions that are substantively identical to those at issue; 
and the FAA is reasonably assured that all interested members of the 
public have had an opportunity to comment and that their comments have 
been fully considered. The FAA, therefore, finds that good cause exists 
for making these special conditions effective upon issuance.

Comments Invited

    Although this action is in the form of final special conditions 
and, for the reasons stated above, is not preceded by notice and an 
opportunity for public comment, comments are invited on this rule. 
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 NM-163.'' The postcard will be date stamped and 
returned to the commenter.

Background

    On October 15, 1998, Rockwell Collins, Business and Regional 
Systems, 400 Collins Road NE., Cedar Rapids, Iowa 52498, made 
application to the FAA for a Supplemental Type Certificate (STC) for 
the Boeing Model 737-300/-400/-500 series airplanes. These airplanes 
are low-wing, pressurized transport category airplanes with twin, wing-
mounted, jet engines. They are capable of seating between 110 and 147 
passengers, depending upon the model and configuration. The proposed 
configuration of these modified airplanes will incorporate a Multi-Mode 
Receiver (MMR) system manufactured by Rockwell Collins. The affected 
aircraft are scheduled for delivery to the first customers in mid-
September 1999.
    The Rockwell Collins MMR is a single integrated unit that enables 
approaches using instrument landing systems, microwave landing systems, 
and global navigation satellite system functions. These functions can 
be susceptible to disruption of both command and response signals as a 
result of electrical and magnetic interference caused by high-intensity 
radiated fields (HIRF) external to the airplane. This disruption of 
signals could result in loss of critical flight displays and 
annunciations, or could present misleading information to the pilot.

Type Certification Basis

    Under the provisions of 14 CFR 21.101 (``Designation of applicable 
regulations''), Rockwell Collins must show that the Boeing Model 737-
300/-400/-500 series airplanes, as modified to include the MMR 
installation, continue to meet the applicable provisions of the 
regulations incorporated by reference in Type Certificate No. A16WE or 
the applicable regulations in effect on the date of

[[Page 47650]]

application for the change. The regulations incorporated by reference 
in the type certificate are commonly referred to as the ``original type 
certification basis.'' The specific regulations included in the 
certification basis for the Boeing Model 737-300/-400/-500 series 
airplanes include 14 CFR part 25, as amended by amendment 25-1 through 
25-3, 25-7, 25-8, and 25-15.

Purpose of Special Conditions

    If the Administrator finds that the applicable airworthiness 
regulations (i.e., 14 CFR part 25) do not contain adequate or 
appropriate safety standards for the Boeing Model 737-300/-400/-500 
series airplanes because of a novel or unusual design feature, special 
conditions are prescribed under the provisions of Sec. 21.16 (``Special 
conditions'').
    In addition to the applicable airworthiness regulations and special 
conditions, the Boeing Model 737-300/-400/-500 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.
    Special conditions, as appropriate, are issued in accordance with 
Sec. 11.49, as required by Secs. 11.28 and 11.29, and become part of 
the airplane's 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 Rockwell Collins 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 
feature, these 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 737-300/-400/-500 series airplanes will 
incorporate the Rockwell Collins MMR system, which performs critical 
functions. The MMR system contains electronic equipment for which 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, this system is 
considered to be a ``novel or unusual design feature.''

Discussion

    There is no specific regulation that addresses requirements for 
protection of 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 that is equivalent to 
that intended by the regulations incorporated by reference, special 
conditions are needed for the Boeing Model 737-300/-400/-500 airplanes 
modified to include the Rockwell Collins MMR system. These special 
conditions will require that this system, which performs critical 
functions, must 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 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 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.

------------------------------------------------------------------------
                                                 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 root-mean-square
  (rms) values.

    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

[[Page 47651]]

Rulemaking Advisory Committee. In general, these standards are less 
critical than the threat level that was previously used as the basis 
for some earlier special conditions.

Applicability

    As discussed above, these special conditions are applicable to the 
Boeing Model 737-300/-400/-500 series airplanes modified by Rockwell 
Collins to include the MMR system. Should Rockwell Collins apply at a 
later date for a design change approval to modify any other model that 
may be included on Type Certificate A16WE and incorporating 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).

Conclusion

    This action affects only certain design features on the Boeing 737-
300/-400/-500 airplanes as modified to include the Rockwell Collins MMR 
system installation. 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 airplanes.
    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. 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 the Boeing Model 737-300/
-400/-500 series airplanes as modified by Rockwell Collins to include 
the Rockwell Collins Multi-Mode Receiver.
    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 
operations 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 August 23, 1999.
Vi L. Lipski,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-22751 Filed 8-31-99; 8:45 am]
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