[Federal Register: December 27, 2002 (Volume 67, Number 249)]
[Rules and Regulations]
[Page 78961-78963]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr27de02-4]
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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]
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