[Federal Register Volume 61, Number 57 (Friday, March 22, 1996)]
[Rules and Regulations]
[Pages 11728-11730]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-7000]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. NM-122; Special Conditions No. 25-ANM-111]
Special Conditions: McDonnell Douglas Model DC9-10, -20, -30, -
40, -50, High-Intensity Radiated Fields
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final special conditions; request for comments.
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SUMMARY: These special conditions are issued for the McDonnell Douglas
DC9-10, -20, -30, -40, -50 airplane. This airplane will utilize new
avionics/electronic systems that provide critical data to the
flightcrew. The applicable regulations do not contain adequate or
appropriate safety standards for the protection of these systems from
the effects of high-intensity radiated fields. 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 14,
1996. Comments must be received on or before April 6, 1996.
ADDRESSES: Comments on these final special conditions, request for
comments, may be mailed in duplicate to: Federal Aviation
Administration, Office of the Assistant Chief Counsel, Attn: Rules
Docket (ANM-7), Docket No. NM-122, 1601 Lind Avenue SW., Renton,
Washington 98055-4056; or delivered in duplicate to the Office of the
Assistant Chief Counsel at the above address. Comments must be marked:
Docket No. NM-122. 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:
Gerald Lakin, FAA, Standardization Branch, ANM-113, Transport Airplane
[[Page 11729]]
Directorate, Aircraft Certification Service, 1601 Lind Avenue SW.,
Renton, Washington, 98055-4056, (206) 227-1187.
SUPPLEMENTARY INFORMATION:
Comments Invited
The FAA has determined that good cause exits 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 and
special conditions 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 comments received. All
comments submitted 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. Persons wishing the FAA to acknowledge receipt of their
comments submitted in response to this request must be submitted with
those comments a self-addressed, stamped postcard on which the
following statement is made: ``Comments to Docket No. NM-122.'' The
postcard will be date stamped and returned to the commenter.
Background
On June 25, 1995, JanzAir Consulting Services, Suite 202, Lee
Wagener Blvd., Fort Lauderdale, Florida 33315-3570, applied for a
supplemental type certificate in the transport airplane category for
the McDonnell Douglas Model DC9-10, -20, -30, -40, -50 airplane. The
DC9-10, -20, -30, -40, -50 is a low swept wing, commercial jet airplane
powered by two Pratt & Whitney JT8D turbofan engines mounted on pylons
extending from the aft fuselage. The airplane has a seating capacity of
80 to 125 passengers, and a maximum takeoff weight of 85,700 to 121,000
pounds. The flight controls will be powered and capable of manual
reversion.
Type Certification Basis
Under the provisions of Sec. 21.101 of the FAR, JanzAir must show,
except as provided in Sec. 25.2, that the modified DC9-10, -20, -30, -
40, -50 meets the applicable provisions of part 25, effective February
1, 1965, as amended by Amendments 25-1 through 25-83. In addition, the
proposed certification basis for the modified DC9-10, -20, -30, -40, -
50 includes part 34, effective September 10, 1990, plus any amendments
in effect at the time of certification; and part 36, effective December
1, 1969, as amended by Amendment 36-1 through the amendment in effect
at the time of certification. No exemptions are anticipated. The
special conditions incorporated herein form an additional part of the
type certification basis. In addition, the certification basis may
include other special conditions that are not relevant to these special
conditions.
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 modified DC9-10, -20, -30, -40, -
50 because of a novel or unusual design feature, special conditions are
prescribed under the provisions of Sec. 21.16 to establish a level of
safety equivalent to that established in the regulations.
Special conditions, as appropriate, are issued in accordance with
Sec. 11.49 of the FAR after public notice, as required by Secs. 11.28
and 11.29, 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 type certificate for that model be amended
later to include any other model that incorporates the same novel or
unusual design feature, or should any other model already included on
the same type certificate be modified to incorporate the same novel or
unusual design feature, the 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 DC9-10, -20, -30, -40, -50 airplane
avionics enhancement will utilize electronic systems that perform
critical functions, including a digital Electronic Flight Instrument
System (EFIS), attitude and heading reference systems (AHRS), and air
data systems (ADS). These systems 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 issued for the modified McDonnell Douglas DC9 which
require that new technology electrical and electronic systems, such as
the EFIS, AHRS and ADS, 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, 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 paragraphs 1 or 2 below.
1. A minimum threat of 100 volts per meter peak 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.
------------------------------------------------------------------------
Peak (V/ Average
Frequency M) (V/M)
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10 KHz-100 KHz........................................ 50 50
100 KHz-500 KHz....................................... 60 60
500 KHz-2000 KHz...................................... 70 70
2 MHz-30 MHz.......................................... 200 200
30 MHz-100 MHz........................................ 30 30
100 MHz-200 MHz....................................... 150 33
200 MHz-400 MHz....................................... 70 70
400 MHz-700 MHz....................................... 4,020 935
700 MHz-1000 MHz...................................... 1,700 170
1 GHz-2 GHz........................................... 5,000 990
2 GHz-4 GHz........................................... 6,680 840
4 GHz-6 GHz........................................... 6,850 310
6 GHz-8 GHz........................................... 3,600 670
8 GHz-12 GHz.......................................... 3,500 1,270
12 GHz-18 GHz......................................... 3,500 360
18 GHz-40 GHz......................................... 2,100 750
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[[Page 11730]]
As discussed above, these special conditions would be applicable
initially to the modified Model DC9-10, -20, -30, -40, -50. Should
JanzAir apply at a later date for a supplemental type certificate to
include another model incorporating the same novel or unusual design
feature, these special conditions would apply to that model as well,
under the provisions of Sec. 21.101(a)(1).
Under standard practice, the effective date of final special
conditions would be 30 days after the date of publication in the
Federal Register. However, as issuance of the supplemental type
certificate for the JanzAir modified DC9 airplane is planned for March
22, 1996, the FAA finds that good cause exists for making these special
conditions effective upon issuance.
Conclusion
This action affects certain design features only on the modified
DC9-10, -20, -30, -40, -50 airplane. It is not a rule of general
applicability and affects only the manufacturer who applied to the FAA
for approval of these features on the airplane.
List of Subjects in 14 CFR Part 25
Aircraft, Aviation safety, Federal Aviation Administration,
Reporting and record keeping requirements.
The authority citation for these proposed special conditions is as
follows:
Authority: 49 U.S.C. app. 1344, 1348(c), 1352, 1354(a), 1355,
1421 through 1431, 1502, 1651(b)(2), 42 U.S.C. 1857f-10, 4321 et
seq., E.O. 11514; and 49 U.S.C. 106(g).
The Special Conditions
Accordingly, the following special conditions are issued as part of
the type certification basis for the JanzAir modified DC9-10, -20, -30,
-40, -50 airplanes.
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 this 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 14, 1996.
James V. Devany,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service, ANM-100.
[FR Doc. 96-7000 Filed 3-21-96; 8:45 am]
BILLING CODE 4910-13-M
