[Federal Register Volume 71, Number 69 (Tuesday, April 11, 2006)]
[Rules and Regulations]
[Pages 18192-18194]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 06-3423]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM344; Special Conditions No. 25-314-SC]


Special Conditions: McDonnell Douglas DC-8-72F 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 DC-
8-72F airplanes modified by Avionics and Systems Integration Group, 
LLC. These modified airplanes will have a novel or unusual design 
feature when compared to the state of technology envisioned in the 
airworthiness standards for transport category airplanes. The 
modification incorporates the installation of Universal Avionics 
Systems Corporation EFI-600 Electronic Flight Instruments 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 17, 
2006.
    We must receive your comments by May 11, 2006.

ADDRESSES: You must mail two copies of your comments to: Federal 
Aviation Administration, Transport Airplane Directorate, Attention: 
Rules Docket (ANM-113), Docket No. NM343, 1601 Lind Avenue SW., Renton, 
Washington 98055-4056. You may deliver two copies to the Transport 
Airplane Directorate at the above address. You must mark your comments: 
Docket No. NM343. You can inspect comments in the Rules Docket 
weekdays, except Federal Holidays, between 7:30 a.m. and 4 p.m.

FOR FURTHER INFORMATION CONTACT: Greg Dunn, FAA, Airplane and Flight 
Crew Interface Branch, ANM-111, Transport Airplane Directorate, 
Aircraft Certification Service, 1601 Lind Avenue SW., Renton, 
Washington 98055-4056; telephone (425) 227-2799; facsimile (425) 227-
1320.

SUPPLEMENTARY INFORMATION:

Comments Invited

    The FAA has determined that notice and opportunity for prior public 
comment is impracticable because these procedures would significantly 
delay certification of the airplane and thus delivery of the affected 
aircraft. 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. The FAA, therefore, finds that 
good cause exists for making these special conditions effective upon 
issuance; however, we invite interested people to take part in this 
rulemaking by sending 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. You may inspect the docket 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 2, 2005, Avionics and Systems Integration Group, LLC, 
2734 Burbank St., Dallas, Texas 75235, applied for a Supplemental Type 
Certificate (STC) to modify McDonnell Douglas DC-8-72F airplanes. These 
models are currently approved under Type Certificate No. 4A25. The 
McDonnell Douglas DC-8-72F is a transport category airplane. The 
airplanes are powered by 4 CFM International Turbofan CFM56-2-C1, 
CFM56-2-C3, CFM56-2-C5, or CFM56-2-C6 engines and have a maximum 
takeoff weight of 335,000 pounds. This airplane operates with a pilot, 
co-pilot, and flight engineer and can hold up to 201 passengers. The 
modification incorporates installation of Universal Avionics Systems 
Corporation EFI-600 Electronic Flight Instruments. The EFI-600 displays 
are replacements for the mechanical heading (HSI) and attitude (ADI) 
instruments. The avionics/electronics and electrical systems installed 
in this airplane have the potential to be vulnerable to high-intensity 
radiated fields (HIRF) external to the airplane.

Type Certification Basis

    Under 14 CFR 21.101, Avionics and Systems Integration Group, LLC, 
must show that the DC-8-72F, as modified, continues 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 certification basis for the 
DC-8-72F airplanes includes provisions from both the Civil Air 
Regulations Part 4B and 14 CFR part 25, as listed on Type Certificate 
No. 4A25. The certification basis also includes special conditions, 
additional requirements, and exemptions listed in the type certificate 
data sheet that are not relevant to these special conditions.
    If the Administrator finds that the applicable airworthiness 
regulations do not contain adequate or appropriate safety standards for 
the McDonnell Douglas DC-8-72F airplanes because of a novel or unusual 
design feature, special conditions are prescribed under Sec.  21.16.
    In addition to the applicable airworthiness regulations and special 
conditions, the DC-8-72F airplanes must comply with the fuel vent and 
exhaust emission requirements of 14 CFR part 34 and the noise 
certification requirements of 14 CFR part 36.
    Special conditions, as defined in 14 CFR 11.19, are issued under 
Sec.  11.38 and become part of the type certification basis under Sec.  
21.101.

[[Page 18193]]

    Special conditions are initially applicable to the model for which 
they are issued. Should the applicant subsequently apply for an STC to 
modify any other model included on Type Certificate No. 4A25 to 
incorporate the same or similar novel or unusual design feature, these 
special conditions would also apply to the other model under Sec.  
21.101.

Novel or Unusual Design Features

    As noted earlier, the McDonnell Douglas DC-8-72F airplanes modified 
by Avionics and Systems Integration Group, LLC, will incorporate dual 
Electronic Primary Flight Displays that perform critical functions. 
This system may be vulnerable to high-intensity radiated fields 
external to the airplane. The current airworthiness standards do not 
contain adequate or appropriate safety standards for the protection of 
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 protection for 
electrical and electronic systems from HIRF. Increased power levels 
from ground-based radio transmitters and the growing use of sensitive 
avionics/electronics and electrical 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 DC-8-72F airplanes 
modified by Avionics and Systems Integration Group, LLC. These special 
conditions require that new avionics/electronics 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 avionics/electronics and electrical 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 (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.

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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
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.
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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 
McDonnell Douglas DC-8-72F airplanes modified by Avionics and Systems 
Integration Group, LLC. Should the applicant subsequently apply for an 
STC to modify any other model included on Type Certificate No. 4A25 to 
incorporate the same or similar novel or unusual design feature, these 
special conditions would apply to that model as well under Sec.  
21.101.

Conclusion

    This action affects only certain novel or unusual design features 
on McDonnell Douglas DC-8-72F airplanes modified by Avionics and 
Systems Integration Group, LLC. It is not a rule of general 
applicability and affects only the applicant which applied to the FAA 
for approval of these features on the airplane.
    The substance of these special conditions has undergone the notice 
and comment procedure in several prior instances and has been derived 
without substantive change from those previously issued. 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

[[Page 18194]]

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 DC-
8-72F airplanes modified by Avionics and Systems Integration Group, 
LLC.
    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 the system 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 17, 2006.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 06-3423 Filed 4-10-06; 8:45 am]
BILLING CODE 4910-13-P