[Federal Register Volume 66, Number 65 (Wednesday, April 4, 2001)]
[Rules and Regulations]
[Pages 17804-17806]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-8189]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM187; Special Conditions No. 25-176-SC]


Special Conditions: McDonnell Douglas Model DC-8-71/-73/-73F 
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 McDonnell Douglas 
Model DC-8-71/-73/-73F series airplanes modified by Hollingsead 
International, Inc. These modified 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 incorporates the installation of new Liquid Crystal Flight 
Instruments, the Attitude Directional Indicator (ADI) and the 
Horizontal Situation Indicator (HSI). The liquid crystal flight 
instruments will utilize electrical and electronic systems 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 March 27, 
2001. Comments must be received on or before May 21, 2001.

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. NM187, 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. NM187. 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: 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:

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 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. 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. 
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 No. NM187.'' The postcard will be date stamped and returned 
to the commenter.

Background

    On October 20, 2000, Hollingsead International, Inc., 7416 
Hollister Avenue, Goleta, California 93117-2538, applied for a 
Supplemental Type Certificate (STC) for the McDonnell Douglas Model DC-
8-71/-73/-73F

[[Page 17805]]

series airplanes. The McDonnell Douglas Model DC-8-71/-73/-73F series 
airplanes are equipped with four CFM56 high bypass turbofan engines. 
The aircraft have a crew of three with additional seating for four, 
consisting of two jump seats in the cockpit and two seats aft of the 
cockpit bulkhead. The aircraft are operated by Emery Worldwide Airlines 
as Class E freighters. The McDonnell Douglas Model DC-8-71/-73/-73F 
airplanes will incorporate Rockwell Collins FPI-920 liquid crystal 
flight instruments. The modified airplanes are scheduled for 
certification in October 2001.
    These functions can be susceptible to disruption of both command 
and response signals as a result of electrical and magnetic 
interference caused by 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, Hollingsead International, 
Inc, must show that the McDonnell Douglas Model DC-8-71/-73/-73F series 
airplanes, as changed, continue to meet the applicable provisions of 
the regulations incorporated by reference in Type Certificate No. 4A25, 
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 included in the certification 
basis for the McDonnell Douglas Model DC-8-71/-73/-73F series airplanes 
include Title 14, Code of Federal Regulations (14 CFR) part 25, as 
amended by Amendment 25-1 through Amendment 25-91.
    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-8-71/-
73/-73F series airplanes because of a novel or unusual design feature, 
special conditions are prescribed under the provisions of Sec. 21.16.
    In addition to the applicable airworthiness regulations and special 
conditions, the McDonnell Douglas Model DC-8-71/-73/-73F series 
airplanes must comply with the fuel vent and exhaust emission 
requirement of 14 CFR part 34 and the noise certification requirement 
of 14 CFR part 36.
    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).
    Special conditions are initially applicable to the model for which 
they are issued. Should the applicant apply 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 also apply to the other model under the 
provisions of Sec. 21.101(a)(1).

Novel or Unusual Design Features

    The McDonnell Douglas Model DC-8-71/-73/-73F series airplanes will 
incorporate the Rockwell Collins FPI-920 liquid crystal flight 
instruments, ADI and HSI, which perform critical functions. The liquid 
crystal flight instruments contain 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. These instruments may be 
vulnerable to HIRF external to the airplane. Accordingly, these 
instruments are considered to be a novel or unusual design feature.

Discussion

    There is no specific regulation that addresses the 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 McDonnell Douglas Model DC-8-71/ 
-73/-73F airplanes modified to include the Rockwell Collins FPI-920 
liquid crystal flight instruments, Attitude Directional Indicator (ADI) 
and Horizontal Situation Indicator (HSI). These special conditions will 
require that these instruments, 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 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.

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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

[[Page 17806]]

 
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.
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    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 
McDonnell Douglas Model DC-8-71/-73/-73F series airplanes modified by 
Hollingsead International, Inc. to include the Rockwell Collins FPI-920 
liquid crystal flight instruments, ADI and HSI. Should Hollingsead 
International apply at a later date for a supplemental type certificate 
to modify any other model included on Type Certificate No. 4A25 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 the McDonnell Douglas Model DC-8-71/ 
-73/-73F series airplanes modified by Hollingsead International, Inc. 
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 has been subjected to the 
notice and comment period 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, 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 the McDonnell Douglas 
Model DC-8-71/-73/-73F series airplanes modified by Hollingsead 
International, 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.

    Issued in Renton, Washington, on March 27, 2001.
Ali Bahrami,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-8189 Filed 4-3-01; 8:45 am]
BILLING CODE 4910-13-U