[Federal Register Volume 67, Number 249 (Friday, December 27, 2002)]
[Rules and Regulations]
[Pages 78961-78963]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-32786]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM241, Special Conditions No. 25-224-SC ]


Special Conditions: McDonnell Douglas Model DC-9-14, DC-9-15, DC-
9-31, DC-9-32, DC-9-32F, DC-9-33F, and DC-9-41 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 Model DC-9-14, 
DC-9-15, DC-9-31, DC-9-32, DC-9-32F, DC-9-33F, and DC-9-41 airplanes 
modified by ABX Air Inc. 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 the 
Innovative Solutions and Support (IS&S) Duplex Reduced Vertical 
Separation Minimum (RVSM) system that performs critical functions. The 
applicable airworthiness regulations do not contain adequate or 
appropriate safety standards for the protection of this system 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 December 10, 
2002. Comments must be received on or before January 27, 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. NM241, 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. NM241.

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 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 July 7, 2002, ABX Air Inc. applied for a Supplemental Type 
Certificate (STC) to modify McDonnell Douglas Model DC-9-14, DC-9-15, 
DC-9-31, DC-9-32, DC-9-32F, DC-9-33F, and DC-9-41 airplanes. The DC-9 
is a two-crew, two-engine, turbine airplane with a maximum weight up to 
122,200 pounds. These models are currently approved under Type 
Certificate A6WE. The modification incorporates the installation of the 
IS&S Duplex RVSM system which will allow for the removal of the 
existing altitude alerter, encoding

[[Page 78962]]

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, Amendment 21-69, effective 
September 16, 1991, ABX Air Inc. must show that McDonnell Douglas Model 
DC-9-14, DC-9-15, DC-9-31, DC-9-32, DC-9-32F, DC-9-33F, and DC-9-41 
airplanes, as changed, continue to meet the applicable provisions of 
the regulations incorporated by reference in Type Certificate No. A6WE, 
or the applicable regulations in effect on the date of application for 
the change. Subsequent changes have been made to Sec.  21.101 as part 
of Amendment 21-77, but those changes do not become effective until 
June 10, 2003. 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 
McDonnell Douglas Model DC-9-14, DC-9-15, DC-9-31, DC-9-32, DC-9-32F, 
DC-9-33F, and DC-9-41 airplanes includes 14 CFR part 25, effective 
February 1, 1965, as amended by Amendments 25-1 through 25-20, except 
for special conditions and exceptions noted in Type Certificate Data 
Sheet (TCDS) A6WE.
    If the Administrator finds that the applicable airworthiness 
regulations (that is, part 25, as amended) do not contain adequate or 
appropriate safety standards for the McDonnell Douglas Model DC-9-14, 
DC-9-15, DC-9-31, DC-9-32, DC-9-32F, DC-9-33F, and DC-9-41 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, McDonnell Douglas Model DC-9-14, DC-9-15, DC-9-31, DC-9-32, 
DC-9-32F, DC-9-33F, and DC-9-41 airplanes must comply with the fuel 
vent and exhaust emission requirements of part 34 and the noise 
certification requirements of 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), Amendment 21-69, effective 
September 16, 1991.
    Special conditions are initially applicable to the model for which 
they are issued. Should ABX Air Inc. apply at a later date for a 
Supplemental Type Certificate to modify any other model included on 
Type Certificate No. A6WE to incorporate the same or similar novel or 
unusual design feature, these special conditions would also apply to 
the other model under the provisions of Sec.  21.101(a)(1), Amendment 
21-69, effective September 16, 1991.

Novel or Unusual Design Features

    As noted earlier, the modified McDonnell Douglas Model DC-9-14, DC-
9-15, DC-9-31, DC-9-32, DC-9-32F, DC-9-33F, and DC-9-41 airplanes will 
incorporate a new altitude display system, the Innovative Solutions and 
Support (IS&S) Duplex Reduced Vertical Separation Minimum (RVSM) 
system, that performs critical functions. This system may be vulnerable 
to HIRF external to the airplane. The current airworthiness standards 
of part 25 do not contain adequate or appropriate safety standards for 
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 
requirements for electrical and electronic systems from HIRF. Increased 
power levels from ground-based radio transmitters and the growing use 
of sensitive avionic/electronic 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 Model DC-9-14, DC-9-15, 
DC-9-31, DC-9-32, DC-9-32F, DC-9-33F, and DC-9-41 airplanes modified by 
ABX Air Inc. These special conditions require that new avionics/
electronic 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

    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 avionic/electronic 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

[[Page 78963]]

 
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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Note.--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 to 
McDonnell Douglas Model DC-9-14, DC-9-15, DC-9-31, DC-9-32, DC-9-32F, 
DC-9-33F, and DC-9-41 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 A6WE 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(a)(1), Amendment 21-69, effective September 16, 1991.

Conclusion

    This action affects only certain novel or unusual design features 
on McDonnell Douglas Model DC-9-14, DC-9-15, DC-9-31, DC-9-32, DC-9-
32F, DC-9-33F, and DC-9-41 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.

    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 McDonnell Douglas Model 
DC-9-14, DC-9-15, DC-9-31, DC-9-32, DC-9-32F, DC-9-33F, and DC-9-41 
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 December 10, 2002.
Ali Bahrami,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 02-32786 Filed 12-26-02; 8:45 am]
BILLING CODE 4910-13-P