[Federal Register Volume 68, Number 182 (Friday, September 19, 2003)]
[Rules and Regulations]
[Pages 54800-54802]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-23970]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM265, Special Conditions No. 25-247-SC ]


Special Conditions: Douglas Models DC-8-61, -61F, -63, -63F, -71, 
-71F, -72, -72F, -73, and -73F 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 Douglas Models DC-8-
61, -61F, -63, -63F, -71, -71F, -72, -72F, -73, and -73F airplanes 
modified by ABX Air, Inc. These airplanes, as modified by ABX Air, 
Inc., will have novel and 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 the Innovative Solutions and Support (IS&S) Duplex 
Reduced Vertical Separation Minimum (RVSM) system which will allow for 
the removal of the existing altitude alerter, encoding altimeters, air 
data computer, and standby altimeter. 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 provided by the existing 
airworthiness standards.

DATES: The effective date of these special conditions is September 10, 
2003. Comments must be received on or before October 20, 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. NM265, 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. NM265.

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-
1149.

SUPPLEMENTARY INFORMATION:

Comments Invited

    The FAA has determined that notice and opportunity for prior public 
comment are 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, 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 4:00 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 November 25, 2002, ABX Air Inc. applied for a supplemental type 
certificate (STC) to modify Douglas Models DC-8-61, -61F, -63, -63F, -
71, -71F, -72, -72F, -73, and -73F airplanes. These models are 
currently approved under Type Certificate 4A25. The modification 
incorporates the installation of the IS&S Duplex RVSM system which will 
allow for the removal of the existing altitude alerter, encoding 
altimeters, air data computer, and standby altimeter. This system uses 
two Air Data Display Units (ADDU) and a single Analog Interface Unit 
(AIU) to replace altitude displays and the air data computer. These 
displays can be susceptible to disruption to both command and response 
signals as a result of electrical and magnetic interference. This 
disruption of signals could result in the loss of all critical flight 
information displays and annunciations or the presentation of 
misleading information to the pilot.

Type Certification Basis

    Under the provisions of 14 CFR 21.101, ABX Air Inc. must show that 
Douglas Models DC-8-61, -61F, -63, -63F, -71, -71F, -72, -72F, -73, and 
-73F 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 certification basis for the modified Douglas 
Models DC-8-61, -61F, -63, -63F, -71, -71F, -72, -72F, -73, and -73F 
airplanes include 14 CFR part 25 effective February 1, 1965 as 
described in Type Certificate Data Sheet 4A25.

[[Page 54801]]

    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 Douglas Models DC-8-61, -61F, -63, 
-63F, -71, -71F, -72, -72F, -73, and -73F 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 Douglas Models DC-8-61, -61F, -63, -63F, -71, -71F, -
72, -72F, -73, and -73F 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 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.
    Special conditions are initially applicable to the models for which 
they are issued. Should ABX Air, Inc., apply at a later date for a 
supplemental type certificate to modify any other models included on 
Type certificate No. 4A25 to incorporate the same or similar novel or 
unusual design feature, the special conditions would also apply to the 
other model under the provisions of Sec.  21.101.

Novel or Unusual Design Features

    The modified Douglas Models DC-8-61, -61F, -63, -63F, -71, -71F, -
72, -72F, -73, and -73F airplanes will incorporate a new altitude 
display system, the Innovative Solutions and Support (IS&S) Duplex 
Reduced Vertical Separation Minimum (RVSM) system, which was not 
available at the time of certification of these airplanes, that 
performs critical functions. This system may be vulnerable to high-
intensity radiated fields (HIRF) external to the airplane.

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 Douglas Models DC-8-61, -61F, -63, -63F, 
-71, -71F, -72, -72F, -73, and -73F airplanes, modified by ABX Air, 
Inc. These special conditions require that new electrical and 
electronic systems, such as the ADDU, 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 the airplane, the 
immunity of critical digital avionic/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 
indicated in the table below for the frequency ranges indicated. Both 
peak and average field strength components from the table below 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 Douglas 
Models DC-8-61, -61F, -63, -63F, -71, -71F, -72, -72F, -73, and -73F 
airplanes modified by ABX Air Inc. Should ABX Air Inc. 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 or 
similar novel or unusual design feature, these special conditions would 
apply to that model as well under the provisions of Sec.  21.101.

Conclusion

    This action affects only certain novel or unusual design features 
on Douglas Models DC-8-61, -61F, -63, -63F, -71, -71F, -72, -72F, -73, 
and -73F airplanes modified by ABX Air 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 these airplanes.
    The substance of these special conditions has been subjected to 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 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.

0
The authority citation for these special conditions is as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701, 44702, 44704.

[[Page 54802]]

The Special Conditions

0
Accordingly, pursuant to the authority delegated to me by the 
Administrator, the following special conditions are issued as part of 
the type certification basis for Douglas Models DC-8-61, -61F, -63, -
63F, -71, -71F, -72, -72F, -73, and -73F airplanes modified by ABX Air 
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 September 10, 2003.
Ali Bahrami,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 03-23970 Filed 9-18-03; 8:45 am]
BILLING CODE 4910-13-P