[Federal Register Volume 65, Number 50 (Tuesday, March 14, 2000)]
[Rules and Regulations]
[Pages 13666-13668]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-6125]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM169; Special Conditions No. 25-157-SC]


Special Conditions: Boeing Model 727-200 and 727-200F Series 
Airplanes; as Modified by Rockwell Collins; 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 727-200 
and 727-200F 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 March 6, 2000. 
Comments must be received on or before April 13, 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. NM169, 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. NM169. 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:

Comments Invited

    Interested persons are invited to participate in the making of 
these proposed special conditions by submitting 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 proposals described in this notice 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

[[Page 13667]]

comments a self-addressed, stamped postcard on which the following 
statement is made: ``Comments to Docket No. NM169.'' The postcard will 
be date stamped and returned to the commenter.

Background

    On September 10, 1999, 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 727-200 and 727-200F series airplanes. These airplanes 
are low-wing, pressurized transport category airplanes with three 
fuselage-mounted jet engines. They are capable of seating between 170 
and 189 passengers, depending upon the model and configuration (727-
200F is not certificated to carry passengers). 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 April 
2000.
    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, Rockwell Collins must show 
that the Boeing Model 727-200 and 727-200F 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. A3WE 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 specific regulations 
included in the certification basis for the Boeing Model 727-200 and 
727-200F series airplanes include Civil Air Regulations (CAR) 4b, as 
amended by amendment 4b-1 through 4b-11.
    If the Administrator finds that the applicable airworthiness 
regulations (i.e., CAR 4b, as amended) do not contain adequate or 
appropriate safety standards for the Boeing Model 727-200 and 727-200F 
series 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, 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 727-200 and 727-200F 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. This system 
may be vulnerable to high-intensity radiated fields external to the 
airplane. 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 727-200 and 727-200F series 
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 rms 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 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
                       Frequency                             meter)
                                                       -----------------
                                                         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 computer 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

[[Page 13668]]

Working Group of the Aviation Rulemaking Advisory Committee.

Applicability

    As discussed above, these special conditions are applicable to the 
Boeing Model 727-200 and 727-200F 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 
included on Type Certificate A3WE 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).

Conclusion

    This action affects only certain design features on the Boeing 
Model 727-200 and 727-200F series airplanes modified by Rockwell 
Collins 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 727-200 
and 727-200F series airplanes as modified by Rockwell Collins.
    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 March 6, 2000.
Vi L. Lipski,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service, ANM-100.
[FR Doc. 00-6125 Filed 3-13-00; 8:45 am]
BILLING CODE 4910-13-P