Special Conditions: McDonnell Douglas DC-8-72F Airplanes; High-Intensity Radiated Fields (HIRF), 18192-18194 [06-3423]
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18192
§ 25.1335
Federal Register / Vol. 71, No. 69 / Tuesday, April 11, 2006 / Rules and Regulations
[Removed]
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:
3. Amend part 25 by removing
§ 25.1335.
I
Issued in Washington, DC, on April 5,
2006.
Marion C. Blakey,
Administrator.
[FR Doc. 06–3467 Filed 4–10–06; 8:45 am]
BILLING CODE 4910–13–P
DEPARTMENT OF TRANSPORTATION
Comments Invited
Federal Aviation Administration
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.
14 CFR Part 25
[Docket No. NM344; Special Conditions No.
25–314–SC]
Special Conditions: McDonnell
Douglas DC–8–72F Airplanes; HighIntensity Radiated Fields (HIRF)
Federal Aviation
Administration (FAA), DOT.
ACTION: Final special conditions; request
for comments.
AGENCY:
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
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SUMMARY:
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Background
On September 2, 2005, Avionics and
Systems Integration Group, LLC, 2734
Burbank St., Dallas, Texas 75235,
applied for a Supplemental Type
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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 highintensity 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
§ 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 § 11.38 and
become part of the type certification
basis under § 21.101.
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11APR1
Federal Register / Vol. 71, No. 69 / Tuesday, April 11, 2006 / Rules and Regulations
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 § 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.
18193
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 cockpitinstalled 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.
Field strength (volts per meter)
Frequency
Peak
10 kHz—100 kHz .............................................................................................................................................
50
100 kHz—500 kHz ...........................................................................................................................................
50
500 kHz—2 MHz .............................................................................................................................................
50
2 MHz—30 MHz ..............................................................................................................................................
100
30 MHz—70 MHz ............................................................................................................................................
50
70 MHz—100 MHz ..........................................................................................................................................
50
100 MHz—200 MHz ........................................................................................................................................
100
200 MHz—400 MHz ........................................................................................................................................
100
400 MHz—700 MHz ........................................................................................................................................
700
700 MHz—1 GHz ............................................................................................................................................
700
1 GHz—2 GHz .................................................................................................................................................
2000
2 GHz—4 GHz .................................................................................................................................................
3000
4 GHz—6 GHz .................................................................................................................................................
3000
6 GHz—8 GHz .................................................................................................................................................
1000
8 GHz—12 GHz ...............................................................................................................................................
3000
12 GHz—18 GHz .............................................................................................................................................
2000
18 GHz—40 GHz .............................................................................................................................................
600
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
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15:47 Apr 10, 2006
Jkt 208001
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 § 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
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Average
50
50
50
100
50
50
100
100
50
100
200
200
200
200
300
200
200
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
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18194
Federal Register / Vol. 71, No. 69 / Tuesday, April 11, 2006 / Rules and Regulations
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
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA–2005–22471; Directorate
Identifier 2005–NM–142–AD; Amendment
39–14550; AD 2006–07–23]
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RIN 2120–AA64
Airworthiness Directives; Boeing
Model 757 Airplanes
Federal Aviation
Administration (FAA), Department of
Transportation (DOT).
AGENCY:
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15:47 Apr 10, 2006
Jkt 208001
ACTION:
Final rule.
SUMMARY: The FAA is adopting a new
airworthiness directive (AD) for all
Boeing Model 757 airplanes. This AD
requires repetitive measurements of the
freeplay of each of the three power
control units (PCUs) that move the
rudder; repetitive lubrication of rudder
components; and corrective actions if
necessary. This AD results from a report
of freeplay-induced vibration of the
rudder. The potential for vibration of
the control surface should be avoided
because the point of transition from
vibration to divergent flutter is
unknown. We are issuing this AD to
prevent excessive vibration of the
airframe during flight, which could
result in divergent flutter and loss of
control of the airplane.
DATES: This AD becomes effective May
16, 2006.
The Director of the Federal Register
approved the incorporation by reference
of certain publications listed in the AD
as of May 16, 2006.
ADDRESSES: You may examine the AD
docket on the Internet at https://
dms.dot.gov or in person at the Docket
Management Facility, U.S. Department
of Transportation, 400 Seventh Street
SW., Nassif Building, room PL–401,
Washington, DC.
Contact Boeing Commercial
Airplanes, P.O. Box 3707, Seattle,
Washington 98124–2207, for service
information identified in this AD.
FOR FURTHER INFORMATION CONTACT:
Dennis Stremick, Aerospace Engineer,
Airframe Branch, ANM–120S, Seattle
Aircraft Certification Office, FAA, 1601
Lind Avenue, SW., Renton, Washington
98055–4056; telephone (425) 917–6450;
fax (425) 917–6590.
SUPPLEMENTARY INFORMATION:
Examining the Docket
You may examine the airworthiness
directive (AD) docket on the Internet at
https://dms.dot.gov or in person at the
Docket Management Facility office
between 9 a.m. and 5 p.m., Monday
through Friday, except Federal holidays.
The Docket Management Facility office
(telephone (800) 647–5227) is located on
the plaza level of the Nassif Building at
the street address stated in the
ADDRESSES section.
Discussion
The FAA issued a notice of proposed
rulemaking (NPRM) to amend 14 CFR
part 39 to include an AD that would
apply to all Boeing Model 757 airplanes.
That NPRM was published in the
Federal Register on September 21, 2005
(70 FR 55321). That NPRM proposed to
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require repetitive measurements of the
freeplay of each of the three power
control units (PCUs) that move the
rudder; repetitive lubrication of rudder
components; and corrective actions if
necessary.
Comments
We provided the public the
opportunity to participate in the
development of this AD. We have
considered the comments received.
Request To Revise Discussion Section’s
Reference to Freeplay-Induced Flutter
Boeing requests that we revise the
wording in the first sentence of the
Discussion section of the NPRM to
replace the phrase ‘‘freeplay-induced
flutter’’ with the phrase ‘‘freeplayinduced vibration.’’ Boeing states that
the event noted in the Discussion
section was not divergent flutter, but
was a constant amplitude event induced
by excessive freeplay. Boeing states that
the service event is consistently
described as freeplay-induced vibration
elsewhere in the NPRM. Boeing points
out that using the phrase ‘‘freeplayinduced flutter’’ in relation to the
service event may lead readers to the
incorrect conclusion that the service
event was divergent flutter.
We agree that the Discussion section
incorrectly stated that there has been
one report of ‘‘freeplay-induced flutter,’’
rather than ‘‘freeplay-induced
vibration.’’ Since the Discussion section
of the preamble does not reappear in the
final rule, we have not changed that
section. However, we have changed the
unsafe condition in the Summary
paragraph and in paragraph (d) of this
AD to include clarification about
freeplay-induced vibration.
Request To Clarify Paragraph (e),
‘‘Compliance’’
Boeing also requests that we change
paragraph (e), ‘‘Compliance,’’ which
states, ‘‘* * * unless the actions have
already been done.’’ Boeing requests
that we clarify the sentence by stating,
‘‘* * * unless the actions have already
been done per the appropriate service
bulletin referenced in paragraph (f)
below.’’ Boeing requests that we give
credit for lubrications accomplished
previously in accordance with the
airplane maintenance manual (AMM).
Boeing also states that the service
bulletins specified in paragraph (f) of
the NPRM institute significant
improvements in the freeplay
measurements and procedures over
those in the AMM. Boeing would like to
ensure that freeplay checks performed
per the AMM are not considered
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]]>Agencies
[Federal Register Volume 71, Number 69 (Tuesday, April 11, 2006)]
[Rules and Regulations]
[Pages 18192-18194]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 06-3423]
-----------------------------------------------------------------------
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.
-----------------------------------------------------------------------
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.
----------------------------------------------------------------------------------------------------------------
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 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
