`[Federal Register Volume 71, Number 21 (Wednesday, February 1, 2006)]
[Proposed Rules]
[Pages 5554-5567]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 06-895]



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Part V





Department of Transportation





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Federal Aviation Administration



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14 CFR Parts 23, 25, et al.



High-Intensity Radiated Fields (HIRF) Protection for Aircraft 
Electrical and Electronic Systems; Proposed Rule

  Federal Register / Vol. 71, No. 21 / Wednesday, February 1, 2006 / 
Proposed Rules  

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Parts 23, 25, 27, and 29

[Docket No. FAA-2006-23657; Notice No. 06-02]
RIN 2120-AI06


High-Intensity Radiated Fields (HIRF) Protection for Aircraft 
Electrical and Electronic Systems

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to add certification standards to protect 
aircraft electrical and electronic systems from high-intensity radiated 
fields (HIRF). This action is necessary due to the vulnerability of 
aircraft electrical and electronic systems and the increasing use of 
high-power radio frequency transmitters. The intended effect of this 
action is to create a safer operating environment for civil aviation by 
protecting aircraft and their systems from the adverse effects of HIRF.

DATES: Send your comments to reach us on or before May 2, 2006.

ADDRESSES: You may send comments, identified by Docket Number FAA-2006-
23657, using any of the following methods:
     DOT Docket Web site: Go to http://dms.dot.gov and follow 
the instructions for sending your comments.
     Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your 
comments.
     Mail: Docket Management Facility; U.S. Department of 
Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, 
Washington, DC 20590-001.
     Fax: 1-202-493-2251.
     Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    For more information, see the SUPPLEMENTARY INFORMATION section of 
this document.
    Privacy: We will post all comments we receive, without change, to 
http://dms.dot.gov, including any personal information you provide. For 
more information, see the Privacy Act discussion in the SUPPLEMENTARY 
INFORMATION section of this document.
    Docket: To read background documents or comments received, go to 
http://dms.dot.gov at any time or to Room PL-401 on the plaza level of 
the Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.

FOR FURTHER INFORMATION CONTACT: Richard E. Jennings, Aircraft 
Certification Service, Aircraft Engineering Division, AIR-130, 1895 
Phoenix Blvd., Suite 450, Atlanta, GA 30349. Telephone (770) 703-6090. 
Or, via e-mail at: [email protected].

SUPPLEMENTARY INFORMATION: 

We Invite Your Comments

    The FAA invites interested persons to participate in this 
rulemaking by submitting written comments, data, or views. We also 
invite comments relating to the economic, environmental, energy, or 
federalism impacts that might result from adopting the proposals in 
this document. The most helpful comments reference a specific portion 
of the proposal, explain the reason for any recommended change, and 
include supporting data.
    We will file in the docket all comments we receive, as well as a 
report summarizing each substantive public contact with FAA personnel 
concerning this proposed rulemaking. 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 9 a.m. and 5 p.m., Monday through Friday, 
except Federal holidays. You may also review the docket using the 
Internet at the web address in the ADDRESSES section.
    Before acting on this proposal, 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 this proposal in light of the comments 
we receive.
    If you want the FAA to acknowledge receipt of your comments on this 
proposal, 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 to you.
    Readers should note that the FAA is publishing elsewhere in today's 
Federal Register a notice of availability of a draft Advisory Circular. 
The Advisory Circular describes one way, but not the only way, to 
comply with the requirements contained in this NPRM. We also invite 
comments on the draft Advisory Circular. Refer to the notice of 
availability for instructions on how file comments on the draft 
Advisory Circular.

Privacy Act

    Anyone is able to search the electronic form of all comments 
received into any of our dockets by the name of the individual 
submitting the comment (or signing the comment, if submitted on behalf 
of an association, business, labor union, etc.). You may review DOT's 
complete Privacy Act Statement in the Federal Register published on 
April 11, 2000 (65 FR 19477-78) or you may visit http://dms.dot.gov.

Proprietary or Confidential Business Information

    Do not file in the docket information that you consider to be 
proprietary or confidential business information. Send or deliver this 
information directly to the person identified in the FOR FURTHER 
INFORMATION CONTACT section of this document. You must mark the 
information that you consider proprietary or confidential. If you send 
the information on a disk or CD ROM, mark the outside of the disk or CD 
ROM and also identify electronically within the disk or CD ROM the 
specific information that is proprietary or confidential.
    Under 14 CFR 11.35(b), when we are aware of proprietary information 
filed with a comment, we do not place it in the docket. We hold it in a 
separate file to which the public does not have access, and place a 
note in the docket that we have received it. If we receive a request to 
examine or copy this information, we treat it as any other request 
under the Freedom of Information Act (5 U.S.C. 552). We process such a 
request under the DOT procedures found in 49 CFR part 7.

Availability of NPRMs

    You can get an electronic copy of this NPRM using the Internet by:
     Searching the DOT electronic docket Web page (http://dms.dot.gov/search);
     Visiting the FAA's Regulations and Policies Web page at 
http://www.faa.gov/regulations_policies/; or
     Accessing the Government Printing Office's Web page 
(http://www.gpoaccess.gov/fr/index.html).
    You can also get a copy by sending a request to the Federal 
Aviation Administration, Office of Rulemaking, 800 Independence Avenue, 
SW., Washington, DC 20591; or by calling (202) 267-9680. Be sure to 
identify the docket number of this NPRM.

Authority for This Rulemaking

    The FAA's authority to issue rules regarding aviation safety is 
found in Title 49 of the United States Code.

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Subtitle I, section 106 describes the authority of the FAA 
Administrator. Subtitle VII, Aviation Programs, describes in more 
detail the agency's authority. This rulemaking is promulgated under the 
authority described in subtitle VII, part A, subpart III, section 
44701(a)(1). Under that section the FAA is charged to promote safe 
flight of civil aircraft in air commerce by prescribing minimum 
standards in the interest of safety for appliances and for the design, 
material, construction, quality of work, and performance of aircraft, 
aircraft engines, and propellers. By prescribing standards to protect 
aircraft electrical and electronic systems from high-intensity radiated 
fields, this proposed regulation is within the scope of the 
Administrator's authority.

Background

Statement of the Problem

    The electromagnetic HIRF environment results from the transmission 
of electromagnetic energy from radar, radio, television, and other 
ground-based, shipborne, or airborne radio frequency (RF) transmitters. 
This environment has the capability of adversely affecting the 
operation of aircraft electric and electronic systems.
    Although the HIRF environment did not pose a significant threat to 
earlier generations of aircraft, in the late 1970s designs for civil 
aircraft were first proposed that included flight-critical electronic 
controls, electronic displays, and electronic engine controls, such as 
those used in military aircraft. These systems are more susceptible to 
the adverse effects of operation in the HIRF environment. Accidents and 
incidents on civil aircraft with flight-critical electrical and 
electronic systems have also brought attention to the need to protect 
these critical systems from high-intensity radiated fields.
    On April 15, 1990, an Airship Industries Airship-600 traversed the 
beam of a highly directional RF broadcast from a Voice of America 
antenna and suffered a complete loss of power in both engines that 
resulted in a collision with trees and terrain during a forced landing 
in North Carolina. The National Transportation Safety Board stated in 
its investigation of the accident that the lack of HIRF certification 
standards for airships was a factor in the accident.
    On March 2, 1999, a Robinson R-44 helicopter passed within 1,000 
meters of the main beam of a high frequency (HF), high energy broadcast 
transmission antenna in Portugal. The pilot reported strong 
interference in the aircraft's communication systems, navigation 
radios, and intercom followed by illumination of the low rotor 
revolutions per minute (RPM) and clutch lights. He further noted that 
engine noise dropped to idle level and the engine and rotor RPM 
indicators dropped. The pilot entered autorotation and landed the 
helicopter successfully with damage only to the main rotor. Following 
landing, the pilot reported all cockpit indications were normal. The 
accident investigation division of Portugal's Instituto Nacional da 
Avia[ccedil][atilde]o Civil stated that the probable cause of the 
incident was severe electromagnetic and RF interference.
    The FAA has issued three airworthiness directives (ADs) in response 
to HIRF effects between 1991 and 1998. In AD 91-03-05, Airship 
Industries Skyship Model 600 Airships, the FAA required the 
installation of a modified ignition control unit because of the 
previously described dual-engine failure that occurred when the 
ignition control units were exposed to HIRF.
    In AD 96-21-13, LITEF GmbH Attitude and Heading System Reference 
(AHRS) Unit Model LCR-92, LCR-92S, and LCR-92H, the FAA stated there 
are indications of an unusual AHRS reaction to certain RF signals that 
could cause the AHRS to give misleading roll and pitch information. As 
a result, the FAA required either (1) the installation of a placard 
adjacent to each primary attitude indicator stating that flight is 
limited to day visual flight rules (VFR) operations only, or, if the 
primary attitude instruments have been deactivated, installation of a 
placard stating that flight is limited to VFR operations only, or (2) a 
modification and inspection of the AHRS wiring cables, a repetitive 
inspection of the cable shielding, and an insertion of a statement in 
the aircraft flight manual regarding unannounced heading errors that 
could occur after switching operation from DG to MAG or operation of 
the  switch in flight with any bank angle.
    In AD 98-24-05, HOAC-Austria Model DV-20 Katana Airplanes, the FAA 
required the replacement of engine electronic modules to prevent 
electromagnetic interference in the modules. The FAA required the 
replacement of the modules because electromagnetic interference could 
cause the airplane's engine to stop due to an interruption in the 
ignition system resulting in loss of control.
    Concern for the protection of electrical and electronic systems in 
aircraft has increased substantially in recent years because of--
    (1) A greater dependence on electrical and electronic systems 
performing functions required for the continued safe flight and landing 
of the aircraft;
    (2) The reduced electromagnetic shielding afforded by some 
composite materials used in aircraft designs;
    (3) The increase in susceptibility of electrical and electronic 
systems to HIRF because of increased data bus or processor operating 
speeds, higher density integrated circuits and cards, and greater 
sensitivities of electronic equipment;
    (4) Expanded frequency usage, especially above 1 gigahertz (GHz);
    (5) The increased severity of the HIRF environment because of an 
increase in the number and power of RF transmitters; and
    (6) The adverse effects experienced by some aircraft when exposed 
to HIRF.

History

    In 1987, the FAA contracted with the Department of Defense 
Electromagnetic Compatibility Analysis Center (ECAC) (currently the 
Joint Spectrum Center) to research and define the U.S. HIRF environment 
to be used for the certification of aircraft and the development of 
Technical Standard Orders. In February 1988, the FAA and the Joint 
Aviation Authorities (JAA) tasked the Society of Automotive Engineers 
(SAE) and the European Organization for Civil Aviation Equipment 
(EUROCAE) to develop guidance material and acceptable means of 
compliance (AMC) documents to support FAA and JAA efforts to develop 
HIRF certification requirements. In response, one SAE panel reviewed 
and revised the assumptions used for ECAC's definition of a HIRF 
environment and published several iterations of that HIRF environment 
for fixed-wing aircraft based on revised assumptions. Another SAE panel 
prepared advisory material to support the FAA's rulemaking efforts.
    Because of efforts undertaken by the FAA and the JAA to harmonize 
the JAA's airworthiness requirements and the FAA's airworthiness 
regulations in the early 1990s, the FAA and the JAA agreed that the 
proposed HIRF certification requirements needed further international 
harmonization before a rule could be adopted.
    As a result, the FAA established the Electromagnetic Effects 
Harmonization Working Group (EEHWG) under the Aviation Rulemaking 
Advisory Committee on Transport Airplane and Engine Issues (57 FR 
58843, December 11, 1992) and tasked it to develop, in coordination 
with the JAA, HIRF certification requirements for aircraft.

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The EEHWG expanded the existing HIRF environments developed by the ECAC 
with the SAE committee to include HIRF environments appropriate for 
aircraft certificated under parts 23, 25, 27, and 29.
    In 1994, the FAA tasked the Naval Air Warfare Center Aircraft 
Division (NAWCAD) to conduct a HIRF electromagnetic field survey study 
to support the efforts of the EEHWG. The EEHWG also received HIRF 
electromagnetic environment data on European transmitters from European 
governments. The EEHWG converted the U.S. and European data into a set 
of harmonized HIRF environments, prepared draft advisory circular/
advisory material joint (AC/AMJ), and also prepared a harmonized FAA 
draft HIRF NPRM and JAA draft HIRF Notice of Proposed Amendment (NPA).
    In November 1997, the EEHWG adopted a set of HIRF environments 
agreed on by the FAA, the JAA, and the industry participants. The HIRF 
environments contained in these proposed rules reflect the HIRF 
environments adopted by the EEHWG. In addition, the information 
contained in this NPRM is based on the draft NPRM/NPA document.

Current Requirements

    Currently, Sec. Sec.  23.1309, 25.1309, 27.1309, and 29.1309 
provide general certification requirements applicable to the 
installation of all aircraft systems and equipment, but they do not 
include specific certification requirements for protection against 
HIRF. AC 23.1309-1C, ``Equipment, Systems, and Installations in Part 23 
Airplanes,'' states that Sec.  23.1309 is not intended to include 
certification requirements for protection against HIRF. Because of the 
lack of specific HIRF certification requirements, special conditions to 
address HIRF have been imposed on applicants seeking issuance of a type 
certificate (TC), amended TC, or supplemental type certificate (STC) 
since 1986. Applicants have the option of demonstrating compliance 
using the external HIRF environment defined in HIRF special conditions 
or a system bench test level of 100 volts per meter (V/m), whichever is 
less. The FAA issued additional interim guidance for the certification 
of aircraft operating in HIRF environments in FAA Notice N8110.71, 
Guidance for the Certification of Aircraft Operating in High-Intensity 
Radiated Field (HIRF) Environments, dated April 2, 1998, with a 
cancellation date of April 2, 1999.

Development of the HIRF Environments

    The HIRF environment was originally categorized into the rotorcraft 
severe, fixed-wing severe, certification, and normal HIRF environments. 
Each of these four HIRF environments was developed based on specific 
assumptions dealing with distance between the aircraft and transmitter, 
appropriate for the class of aircraft under consideration. The EEHWG 
investigated the likelihood that fixed wing aircraft and rotorcraft 
operate in the vicinity of high power transmitters. The EEHWG also 
investigated testing practicality and availability of test facilities 
for the HIRF environment levels. The EEHWG used these factors to select 
the levels for the HIRF environments used in the proposal.
    The U.S. HIRF environments were calculated by the NAWCAD based on 
the assumptions agreed on by the EEHWG, using unclassified and 
classified data on government and civilian transmitters, such as 
electromagnetic effects databases, technical manuals, and information 
provided by transmitter operators.
    In developing the U.S. rotorcraft severe, fixed-wing severe, 
certification, and normal HIRF environments, the NAWCAD reviewed the 
Joint Spectrum Center's HIRF data and updated the transmitter 
information to ensure the most current licensed and authorized 
transmitters were used. A subset of data was created that contained the 
licensing information and equipment descriptions on the 25 highest 
radiated power transmitters in each of the following 17 HIRF frequency 
bands for each of the HIRF environments: 10 to 100 kilohertz (kHz), 100 
to 500 kHz, 500 kHz to 2 megahertz (MHz), 2 to 30 MHz, 30 to 70 MHz, 70 
to 100 MHz, 100 to 200 MHz, 200 to 400 MHz, 400 to 700 MHz, 700 MHz to 
1 GHz, 1 to 2 GHz, 2 to 4 GHz, 4 to 6 GHz, 6 to 8 GHz, 8 to 12 GHz, 12 
to 18 GHz, and 18 to 40 GHz.
    The NAWCAD then selected the five transmitters with the highest 
peak and the five transmitters with the highest average radiated power 
in each frequency band to develop the HIRF environments. The NAWCAD 
performed further analysis and investigation to confirm the 
transmitters were operating and producing the radiated power indicated 
in their licensing information. If one of the transmitters was located 
in prohibited or restricted airspace, the NAWCAD noted that 
information, removed the transmitter from consideration as a potential 
HIRF transmitter, and selected the next lower radiated power 
transmitter not in prohibited or restricted airspace. Once the five 
highest peak and five highest average power transmitters were 
identified and confirmed operational, the NAWCAD recalculated their 
electromagnetic field strengths, in V/m. Finally, the NAWCAD created 
each U.S. HIRF environment using the transmitters with the highest 
calculated field strength in each of the 17 frequency bands for peak 
and average power. JAA-member nations undertook similar efforts to 
develop the European HIRF environments.
    To create the harmonized HIRF environments, the EEHWG compared the 
U.S. and European HIRF environments and selected the transmitters with 
the highest field strength values for each of the 17 frequency bands 
for peak and average power.
    The harmonized HIRF environments are based on the individual U.S. 
and European HIRF environments and form an estimate of the 
international electromagnetic field strength, in V/m, over a frequency 
range from 10 kHz to 40 GHz. The FAA, JAA, and other governmental and 
international agencies, such as the International Civil Aviation 
Organization (ICAO) and the International Telecommunications Union, 
plan to monitor the future growth of the harmonized HIRF environment.
    The following general assumptions were used to develop the HIRF 
environments:
    (1) The HIRF environment was divided into 17 frequency bands, 
ranging from 10 kHz to 40 GHz.
    (2) The main-beam illumination and maximum-beam gain of the 
transmitting antenna were used.
    (3) The duty cycle of pulsed transmitters was used to calculate the 
average power; however, the modulation of a transmitted signal was not 
considered. The duty cycle was defined as the product of pulse width 
and pulse repetition frequency and applied only to pulsed systems.
    (4) Constructive ground reflections (direct and reflected waves) of 
HF signals were assumed to be in phase.
    (5) The noncumulative field strength was calculated; however, 
simultaneous illumination by more than one antenna was not considered.
    (6) Near-field corrections were used for aperture and phased-array 
antennas.
    (7) Field strengths were calculated at minimum distances dependent 
on the locations of the transmitter and the aircraft.
    (8) The field strength was calculated for each frequency band using 
the maximum field strength for all

[[Page 5557]]

transmitters within that band for peak and average power, given in V/m. 
The field strength values were expressed in root-mean-square (rms) 
units measured during the peak of the modulation cycle, as many 
laboratory instruments indicate amplitude. The true peak field strength 
values will be higher by a factor of the square root of two.
    (9) The peak field strength was based on the transmitter's maximum 
authorized peak power, maximum antenna gain, and system losses.
    (10) The average field strength was based on the transmitter's 
maximum authorized peak power, maximum duty cycle, maximum antenna 
gain, and system losses.
    (11) The aircraft's altitude and the transmitter's maximum antenna 
elevation were taken into account. The slant range was defined as the 
line-of-sight distance between the transmitter and the aircraft. The 
adjusted slant range was defined as the line-of-sight distance at which 
the aircraft encounters the maximum illumination from an elevation-
limited antenna's main beam. If the transmitter's maximum antenna 
elevation angle was not available, 90 degrees was assumed.
    (12) Transmitters located in prohibited areas, restricted areas, or 
warning areas (ICAO danger areas) were not included.
    (13) Proposed special-use airspace (SUA) boundaries were defined 
for selected high-power transmitters. The size of the proposed SUA was 
derived from transmitter data and, therefore, varied from transmitter 
site to transmitter site. For transmitters located within a proposed 
SUA, the transmitter field strength was assessed at the boundary of the 
proposed SUA.
    (14) Transmitters with experimental licenses and non-airport mobile 
tactical military transmitters were excluded.
    (15) Certain transmitters have the capability to reduce power or 
restrict scanning coverage if aircraft operate in close vicinity. This 
capability was assumed to be operating for calculating illumination and 
power density.
    (16) Transmitter losses into the antenna were estimated at 3 
decibels in the U.S. HIRF environment, unless transmitter data were 
available.
    For further information on the development of the HIRF 
environments, consult NAWCAD Technical Memorandum, Report No. 
NAWCADPAX-98-156-TM, High-intensity Radiated Field External 
Environments for Civil Aircraft Operating in the United States of 
America (Unclassified), dated November 12, 1998. A copy of the NAWCAD 
Technical Memorandum is available in the docket.

                                    Table I.--Summary of Transmitter Locations Used To Develop the HIRF Environments
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                     Transmitter distance from aircraft (feet, slant or adjusted (adj.) slant range)
     Geographic location of     ------------------------------------------------------------------------------------------------------------------------
       transmitter source              Rotorcraft severe              Fixed-wing severe       Certification (all aircraft)      Normal (all aircraft)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Airport \1\, heliport, and
 offshore platform \2\:
Fixed:
    Air route/Airport            300 adj. slant...............  500 adj. slant..............  500 adj. slant..............  500 adj. slant.
     surveillance radar.
    All others.................  100 slant....................  250 adj. slant..............  250 adj. slant..............  250 adj. slant.
Mobile:
    Aircraft weather radar.....  150 slant....................  150 slant...................  150 slant...................  250 slant.
    All others.................  50 slant.....................  50 slant....................  50 slant....................  50 slant.
Land-based (other than airport
 and heliport) \3\:
    HIRF SUA...................  Edge of SUA..................  Edge of SUA.................  Edge of SUA.................  Edge of SUA.
All others (distance from
 facility):
    > 0-3 nautical miles (nm)..  100 slant....................  500 adj. slant..............  500 adj. slant..............  500 adj. slant.
    3-5 nm.....................  100 slant....................  500 adj. slant..............  1000 adj. slant.............  1000 adj. slant.
    5-10 nm....................  100 slant....................  500 adj. slant..............  1000 adj. slant.............  1500 adj. slant.
    10-25 nm...................  100 slant....................  500 adj. slant..............  1000 adj. slant.............  2500 adj. slant.
    > 25 nm....................  100 slant....................  500 adj. slant..............  1000 adj. slant.............  1000 adj. slant.
Ship-based transmitters \4\:
    All ships..................  500 slant....................  500 adj. slant..............  1000 adj. slant.............  Not applicable.
Air-to-air \5\:
    Interceptor................  Not applicable...............  100 slant...................  100 slant...................  Not applicable.
    All others.................  Not applicable...............  500 slant...................  500 slant...................  Not applicable.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ The airport environment consisted of all fixed and mobile transmitters located within a 5-nm boundary around the airport. The fixed transmitters
  considered included the marker beacon, localizer, very-high-frequency omnirange (VOR) navigation, glide slope, tactical air navigation (TACAN),
  weather radar, telemetry, ground controlled approach radar, distance measuring equipment, microwave landing system (MLS), airport surveillance radar,
  air route surveillance radar, ultra high frequency/very high frequency (UHF/VHF) communications, and air traffic control radar beacon system (ATCRBS)
  interrogator. The mobile transmitters considered included all the ground transmitters not in a fixed location, such as VHF radios on ground support
  equipment and the following aircraft transmitters: High frequency (HF)/UHF communication, TACAN, Doppler navigation radar, radio altimeter, weather
  radar, and ATCRBS beacon.
\2\ The heliport and offshore platform environments consisted of all transmitters, fixed and mobile, located on commercial heliport and offshore
  platforms. The transmitters considered included satellite, HF, and UHF/VHF communications, VOR navigation, homing beacons, weather radar, surface
  search radar, and MLS.
\3\ The land-based environment (other than the airport and heliport environments) consisted of all ground transmitters not located on an airport,
  heliport, or offshore platform. The transmitters considered included sounders, submarine and UHF/VHF communication, radar astronomy, land mobile
  equipment, test and training equipment, weather radar, national defense radar, long-range navigation (LORAN), television broadcast, air route
  surveillance radar, and satellite uplinks.
\4\ The ship-based environment consisted of all transmitters located on all commercial and military ships located at sea or in harbors near airports.
  The transmitters considered included air search radar, fire control radar, satellite, HF, and UHF/VHF communications, TACAN, weather radar, surface
  search radar, MLS, and ATCRBS interrogator.
\5\ The air-to-air environment consisted only of those transmitters on military aircraft because the transmitters on civilian aircraft were considered
  in the mobile airport environment. For military aircraft on intercept courses all non-hostile transmitters were assumed to be operational, and for all
  military aircraft on intercept courses all transmitters were assumed to be operational.


[[Page 5558]]

HIRF Environments

 Table II.--HIRF Environments, as Developed by the EEHWG and as Proposed
                             in This Notice
------------------------------------------------------------------------
   HIRF Environment, as developed by the        HIRF Environment, as
                   EEHWG                       proposed in this notice
------------------------------------------------------------------------
Fixed-wing Severe.........................  Not used.
Rotorcraft Severe.........................  HIRF Environment III.
Certification.............................  HIRF Environment I.
Normal....................................  HIRF Environment II.
------------------------------------------------------------------------

    The fixed-wing severe and rotorcraft severe HIRF environments 
present worst-case estimates of the electromagnetic field strength in 
the airspace in which fixed-wing aircraft and rotorcraft operations, 
respectively, are permitted. The fixed-wing severe HIRF environment, as 
shown in table III, was used only to develop the certification HIRF 
environment. The rotorcraft severe HIRF environment, as shown in table 
IV, is identical to HIRF environment III as proposed in this notice.
    The certification HIRF environment, as shown in table V (HIRF 
environment I as proposed in this notice) provides test and analysis 
levels to demonstrate that an aircraft and its systems meet HIRF 
certification requirements. HIRF environment I is based on likely 
aircraft separation distances and takes into account high peak power 
microwave transmitters that typically do not operate continuously at 
their maximum output levels. Based on statistical analysis of aircraft 
operations, the EEHWG determined that the assumptions used for 
calculating HIRF environment I were more appropriate for aircraft 
certification than the assumptions of the fixed-wing severe HIRF 
environment; therefore, the fixed-wing severe HIRF environment is not 
used in the proposed rules.
    The normal HIRF environment, as shown in table VI (HIRF environment 
II as proposed in this notice) also provides test and analysis levels 
to demonstrate that the aircraft and its systems meet HIRF 
certification requirements. HIRF environment II is an estimate of the 
electromagnetic field strength in the airspace above an airport or 
heliport in which routine departure and arrival operations take place. 
HIRF environment II also takes into account high peak power microwave 
transmitters that typically do not operate continuously at their 
maximum output levels. The EEHWG determined that the assumptions used 
for HIRF environment II are most appropriate for aircraft operating in 
the vicinity of airports.

             Table III.--Fixed-Wing Severe HIRF Environment
------------------------------------------------------------------------
                                                    Field strength (V/m)
                     Frequency                     ---------------------
                                                       Peak     Average
------------------------------------------------------------------------
10 kHz-100 kHz....................................         50         50
100kHz-500 kHz....................................         60         60
500kHz-2 MHz......................................         70         70
2 MHz-30 MHz......................................        200        200
30 MHz-100 MHz....................................         30         30
100 MHz-200 MHz...................................         90         30
200 MHz-400 MHz...................................         70         70
400 MHz-700 MHz...................................        730         80
700 MHz-1 GHz.....................................      1,400        240
 1 GHz-2 GHz......................................      3,300        160
 2 GHz-4 GHz......................................      4,500        490
 4 GHz-6 GHz......................................      7,200        300
 6 GHz-8 GHz......................................      1,100        170
 8 GHz-12 GHz.....................................      2,600        330
 12 GHz-18 GHz....................................      2,000        330
 18 GHz-40 GHz....................................      1,000        420
------------------------------------------------------------------------


              Table IV.--Rotorcraft Severe HIRF Environment
                         [HIRF Environment III]
------------------------------------------------------------------------
                                                     Field strength  (V/
                                                             m)
                     Frequency                     ---------------------
                                                       Peak     Average
------------------------------------------------------------------------
10 kHz-100 kHz....................................        150        150
100 kHz-400 MHz...................................        200        200
400 MHz-700 MHz...................................        730        200
700 MHz-1 GHz.....................................      1,400        240
1 GHz-2 GHz.......................................      5,000        250
2 GHz-4 GHz.......................................      6,000        490
4 GHz-6 GHz.......................................      7,200        400
6 GHz-8 GHz.......................................      1,100        170
8 GHz-12 GHz......................................      5,000        330
12 GHz-18 GHz.....................................      2,000        330
18 GHz-40 GHz.....................................      1,000        420
------------------------------------------------------------------------


                Table V.--Certification HIRF Environment
                          [HIRF Environment I]
------------------------------------------------------------------------
                                                     Field strength  (V/
                                                             m)
                     Frequency                     ---------------------
                                                       Peak     Average
------------------------------------------------------------------------
10 MHz-2 MHz......................................         50         50
2 MHz-30 MHz......................................        100        100
30 MHz-100 MHz....................................         50         50
100 MHz-400 MHz...................................        100        100
400 MHz-700 GHz...................................        700         50
700 GHz-1 GHz.....................................        700        100
1 GHz-2 GHz.......................................      2,000        200
2 GHz-6 GHz.......................................      3,000        200
6 GHz-8 GHz.......................................      1,000        200
8 GHz-12 GHz......................................      3,000        300
12 GHz-18 GHz.....................................       2000        200
18 GHz-40 GHz.....................................        600        200
------------------------------------------------------------------------


                   Table VI.--Normal HIRF Environment
                          [HIRF Environment II]
------------------------------------------------------------------------
                                                     Field strength  (V/
                                                             m)
                     Frequency                     ---------------------
                                                       Peak     Average
------------------------------------------------------------------------
10 kHz-500 kHz....................................         20         20
500 kHz-2 MHz.....................................         30         30
2 MHz-30 MHz......................................        100        100
30 MHz-100 MHz....................................         10         10
100 MHz-200 MHz...................................         30         10
200 MHz-400 MHz...................................         10         10
400 MHz-1 GHz.....................................        700         40
1 GHz-2 GHz.......................................      1,300        160
2 GHz-4 GHz.......................................      3,000        120
4 GHz-6 GHz.......................................      3,000        160
6 GHz-8 GHz.......................................        400        170
8 GHz-12 GHz......................................      1,230        230
12 GHz-18 GHz.....................................        730        190
18 GHz-40 GHz.....................................        600        150
------------------------------------------------------------------------

Equipment Test Levels

    The EEHWG developed four equipment HIRF test levels, which have 
been included in this proposal. The four test levels were created using 
typical aircraft HIRF protection characteristics and data from aircraft 
service experience to provide the ability to perform testing in a 
laboratory environment.
    Equipment HIRF test levels 1 and 2 are based on the normal HIRF 
environment reduced by typical aircraft attenuation. The typical 
aircraft attenuation was determined using the mean attenuation measured 
on a number of transport airplanes, small airplanes, and rotorcraft. 
Equipment HIRF test level 3 is based on the normal HIRF environment 
reduced by the aircraft attenuation for a specific aircraft. Equipment 
HIRF test level 4 was developed to provide assurance for HIRF 
protection based on service experience for certain aircraft systems. To 
develop test level 4, the EEHWG reviewed all available reports of HIRF 
interference. This equipment HIRF test level was selected to minimize 
the effects of HIRF and is 5 to 10 times higher than the system test 
levels currently used.

General Discussion of the Proposal

HIRF Certification Requirements

    The proposed HIRF certification requirements would apply to an 
applicant for a new type certificate and to an applicant for a change 
to an existing type certificate when the certification basis for the 
aircraft includes the proposed requirements. The applicability of the 
proposed requirements to an applicant for a change to an existing type 
certificate would be governed by the provisions

[[Page 5559]]

contained in current Sec.  21.101 Designation of applicable regulations 
(generally referred to as the ``changed product rule''). Specifically, 
Sec.  21.101 would apply when an applicant intends to change a type 
certificate to obtain approval for the installation of an electrical or 
electronic system on an existing aircraft model. Accordingly, an 
electrical or electronic system that has previously met HIRF special 
conditions may require additional testing for it to be found in 
compliance with the HIRF environments specified in this proposal. The 
FAA specifically invites comments that discuss the effect (including 
any potential costs) of Sec.  21.101 on the ability of applicants to 
comply with the proposed HIRF certification requirements.
    The hazard assessment conducted to show compliance with Sec. Sec.  
23.1309, 25.1309, 27.1309, and 29.1309 then could be used to assist in 
determining the appropriate HIRF certification requirements for the 
aircraft electrical and electronic systems. HIRF certification 
requirements in the proposed rule would be established only for 
aircraft electrical and electronic systems whose failure would: (1) 
Prevent the continued safe flight and landing of the aircraft; (2) 
significantly reduce the capability of the aircraft or the ability of 
the flightcrew to respond to an adverse operating condition; or (3) 
reduce the capability of the aircraft or the ability of the flightcrew 
to respond to an adverse operating condition. This resulting failure 
classification would determine which HIRF environment the aircraft and/
or electrical and electronic systems would be exposed to during 
certification testing.
    Under the proposed rule, electrical and electronic systems that 
perform a function whose failure would prevent the continued safe 
flight and landing of the aircraft must be designed and installed so 
that--
    (1) Each function is not affected adversely during and after the 
aircraft is exposed to HIRF environment I;
    (2) Each electrical and electronic system automatically recovers 
normal operation, in a timely manner, after the aircraft is exposed to 
HIRF environment I, unless this conflicts with other operational or 
functional requirements of that system; and
    (3) Each electrical and electronic system is not adversely affected 
during and after the aircraft is exposed to HIRF environment II.

An example of an electrical or electronic system whose failure would 
prevent the continued safe flight and landing of the aircraft is a full 
authority digital electronic engine control (FADEC).
    In addition, rotorcraft would be required to meet additional HIRF 
certification standards because rotorcraft operating under VFR do not 
have to comply with the same minimum safe altitude restrictions for 
airplanes in Sec.  91.119 and, therefore, may operate closer to 
transmitters. Accordingly, for functions required during operation 
under VFR whose failure would prevent the continued safe flight and 
landing of the rotorcraft, the electrical and electronic systems that 
perform such a function, considered separately and in relation to other 
systems, would be required to be designed and installed so that each 
function is not adversely affected during and after the time the 
rotorcraft is exposed to HIRF environment III. Rotorcraft operating 
under instrument flight rules (IFR) have to comply with more 
restrictive altitude limitations and, therefore, electrical and 
electronic systems with functions required for IFR operations would be 
required to not be adversely affected when the rotorcraft is only 
exposed to HIRF environment I.
    The proposal would mandate that each electrical and electronic 
system that performs a function whose failure would reduce 
significantly the capability of the aircraft or the ability of the 
flightcrew to respond to an adverse operating condition be designed and 
installed so the system is not affected adversely when the equipment 
providing these functions is exposed to equipment HIRF test level 1, 2, 
or 3. A system that is not adversely affected by any one of these test 
levels would be considered acceptable. Test levels 1 and 2 have 
equivalent energy, but provide different modulation applications. This 
flexibility permits test laboratories to use existing test equipment. 
Test level 2 allows an applicant to use equipment test levels developed 
for the specific aircraft being certificated. Any one of these test 
levels may be used to demonstrate HIRF protection. Examples of 
electrical and electronic systems whose failure would significantly 
reduce the capability of the aircraft or the ability of the flightcrew 
to respond to an adverse operating condition are an instrument landing 
system (ILS) receiver or a VHF communications receiver.
    Lastly, under the proposed rule, each electrical and electronic 
system that performs a function whose failure would reduce the 
capability of the aircraft or the ability of the flightcrew to respond 
to an adverse operating condition must be designed and installed so the 
system is not affected adversely when the equipment providing these 
functions is exposed to equipment HIRF test level 4. An example of an 
electrical or electronic system whose failure would reduce the 
capability of the aircraft or the ability of the flightcrew to respond 
to an adverse operating condition is a cabin pressurization system.
    HIRF environments I, II, and III, and equipment HIRF test levels 1, 
2, 3, and 4 would be found in proposed appendixes to the affected 
parts.

Compliance With HIRF Certification Requirements

    Acceptable operation of a system or equipment installation during 
exposure to a HIRF environment or equipment HIRF test level could be 
shown through similarity with existing systems, analyses, testing, or 
any combination acceptable to the FAA. However, certification by 
similarity could not be used for a combination of new aircraft design 
and new equipment design. In addition, service experience alone would 
not be acceptable because such experience may not include exposure to 
HIRF environments. Acceptable system performance could be attained by 
demonstrating that the system under consideration continued to perform 
its intended function. Deviations from the performance specifications 
of systems under consideration could be acceptable, but they would need 
to be assessed independently to ensure the effects of the deviations 
neither cause nor contribute to conditions that would affect adversely 
aircraft operational capabilities. When deviations in performance occur 
as a consequence of the system's or equipment's exposure to the HIRF 
environment or equipment HIRF test level, an assessment of the 
acceptability of the performance should be made. This assessment should 
be supported by data and analyses.
    Because aircraft control system failures and malfunctions could 
contribute more directly and abruptly to the continued safe flight and 
landing of an aircraft than display system failures and malfunctions, 
compliance with the proposed rule for systems performing display 
functions would not require aircraft level testing. Therefore, systems 
performing display functions could demonstrate compliance with the 
appropriate HIRF certification requirements in a laboratory using 
generic HIRF attenuation curves for that aircraft developed during 
previous HIRF aircraft level testing. The compliance should address 
instructions for continued airworthiness of the HIRF protection 
features.

[[Page 5560]]

Paperwork Reduction Act

    In accordance with the Paperwork Reduction Act of 1995 (44 U.S.C. 
3507(d)), the FAA has determined that there are no requirements for 
information collection associated with this proposed rule.

International Compatibility

    In keeping with U.S. obligations under the Convention on 
International Civil Aviation, it is FAA policy to comply with 
International Civil Aviation Organization (ICAO) Standards and 
Recommended Practices to the maximum extent practicable. The FAA 
determined that there are no ICAO Standards and Recommended Practices 
that correspond to these proposed regulations.

Economic Evaluation, Regulatory Flexibility Determination, 
International Trade Impact Assessment, and Unfunded Mandate Assessment

    Changes to Federal regulations must undergo several economic 
analyses. First, Executive Order 12866 directs that each Federal agency 
shall propose or adopt a regulation only upon a reasoned determination 
that the benefits of the intended regulation justify its costs. Second, 
the Regulatory Flexibility Act of 1980 requires agencies to analyze the 
economic impact of regulatory changes on small entities. Third, the 
Trade Agreements Act of 1979 (19 U.S.C. 2531-2533) prohibits agencies 
from setting standards that create unnecessary obstacles to the foreign 
commerce of the United States. In developing U.S. standards, this Trade 
Act requires agencies to consider international standards and, where 
appropriate, to be the basis of U.S. standards. Fourth, the Unfunded 
Mandates Reform Act of 1995 (Pub. L. 104-4) requires agencies to 
prepare a written assessment of the costs, benefits, and other effects 
of proposed or final rules that include a Federal mandate likely to 
result in the expenditure by State, local, or tribal governments, in 
the aggregate, or by the private sector, of $100 million or more 
annually (adjusted for inflation). This portion of the preamble 
summarizes the FAA's analysis of the economic impacts of this NPRM. We 
suggest readers seeking greater detail read the full regulatory 
evaluation, a copy of which we have placed in the docket for this 
rulemaking.
    In conducting these analyses, FAA has determined that this 
proposal: (1) Has benefits that justify its costs; (2) is not an 
economically ``significant regulatory action'' as defined in section 
3(f) of Executive Order 12866; (3) is not ``significant'' as defined in 
DOT's Regulatory Policies and Procedures; (4) would not have a 
significant economic impact on a substantial number of small entities; 
(5) is consistent with the Trade Agreements Act of 1979 in that it 
appropriately adopts international standards as the basis of U.S. 
standards; and (6) would not impose an unfunded mandate on state, 
local, or tribal governments, or on the private sector.

Who Is Affected By This Rulemaking

    Manufacturers of transport category airplanes incur no incremental 
costs; manufacturers of transport category rotorcraft and non-transport 
category aircraft incur varying costs.
    Occupants in affected aircraft receive safety benefits.

Assumptions and Standard Values

     Discount rate: 7%.
     Period of analysis: Costs--based on a 10-year production 
period. Benefits--based on 25-year operating lives of newly-
certificated aircraft.
     Value of statistical fatality avoided: $3 million.
     Benefits/costs are evaluated from two perspectives: (1) 
The ``base case''--a comparison of the costs and associated benefits of 
current industry practice to those of the proposed rule, and (2) the 
``regulatory case''--a comparison of the costs and associated benefits 
of complying with current U.S. special conditions to those of the 
proposed rule. Current industry practice for manufacturers of all 
airplanes certificated under part 25, for manufacturers of the majority 
of parts 23/29 aircraft, and for manufacturers of a sizeable minority 
of part 27 rotorcraft, is to comply with JAA's (now EASA's) HIRF 
interim standards (JAA's version of special conditions), which are 
equivalent to those of the NPRM. On the other hand, manufacturers of 
the remaining aircraft (some part 23 and part 29 aircraft and most part 
27 rotorcraft) currently meet only U.S. special conditions, which are 
not as stringent as those set forth in the NPRM. These affected 
aircraft manufacturers would experience additional costs under the 
proposed rule.
     The proposed rule is assumed to be 100 percent effective 
in preventing HIRF-related accidents.

Alternatives Considered

    Although earlier and current special condition levels of HIRF 
protection were considered, JAA's HIRF standards were selected for this 
NPRM because of both the proven high levels of protection demonstrated 
and the potential cost savings resulting from harmonization of FAA and 
JAA/EASA requirements.

Costs and Benefits of This Rulemaking

Costs

                       Estimated Discounted Costs
                    [$millions over a 10-year period]
------------------------------------------------------------------------
                                              Current         Special
                                           practice  to    conditions to
                                               NPRM            NPRM
------------------------------------------------------------------------
Part 23 certificated airplanes..........            21.8            72.8
Part 25 certificated airplanes..........               0           308.1
Part 27 certificated rotorcraft.........             1.5             2.0
Part 29 certificated rotorcraft.........             5.3            26.6
                                         -----------------
    Total estimated costs...............           $28.6          $409.5
------------------------------------------------------------------------

    In the first column (or, the base case, which reflects actual costs 
to industry), there are no additional HIRF-protection costs for 
manufacturers of part 25 airplanes and relatively low incremental costs 
for manufacturers of the majority of parts 23 and 29 aircraft, since 
U.S. manufacturers of these compliant aircraft currently meet JAA's/
EASA's HIRF standards in order to market their aircraft in Europe. 
There are moderate incremental costs for manufacturers of the remaining 
portion of parts 23/29 aircraft and relatively lower costs for the 
majority of part 27 rotorcraft that do not currently meet JAA's/EASA's 
HIRF standards (equivalent to the requirements in this proposal) either

[[Page 5561]]

because (1) their aircraft do not yet have complex electronic systems 
installed or (2) they have chosen not to market their aircraft abroad. 
This ``current practice to proposed rule'' is the base perspective in 
this analysis. The total estimated ten-year costs of $28.6 million (the 
sum of column one) represent the true incremental impact on the 
industry.
    However, most manufacturers of parts 23, 25, 27, and 29 aircraft 
believe that U.S. special conditions afford sufficient protection from 
HIRF. Therefore, in the second column (or, the regulatory case, 
``special conditions to NPRM''), the FAA shows the incremental 
compliance costs between the current U.S. special condition levels 
(essentially equivalent to industry's self-determined protection) and 
the NPRM's more stringent requirements. These regulatory costs equal 
$409.5 million, and represent the costs for more robust HIRF protection 
that industry would not have voluntarily incurred.

Benefits

    Estimated benefits of this proposal are the accidents, incidents, 
and fatalities avoided as a result of increased protection from HIRF-
effects provided to electric and electronic systems. Quantified 
benefits are partly based on a study titled ``High-Intensity Radiated 
Fields (HIRF) Risk Analysis,'' by EMA Electro Magnetic Applications, 
Inc. of Denver, Co. (report DOT/FAA/AR-99/50, July 1999); the complete 
study is available in the docket for this rulemaking. Using the study's 
risk analysis results for airplanes certificated under parts 23 and 25 
and FAA accident/incident data for rotorcraft certificated under parts 
27 and 29, the FAA calculated the difference between the expected 
number of accidents under the proposed standards versus those that 
could be expected if current U.S. special condition levels were 
maintained in the future in lieu of the proposed standards.

                      Estimated Discounted Benefits
                    [$millions over a 34-year period]
------------------------------------------------------------------------
                                              Current         Special
                                           practice  to   conditions  to
                                               NPRM            NPRM
------------------------------------------------------------------------
Part 23 certificated airplanes..........            37.1           123.5
Part 25 certificated airplanes..........               0         3,683.9
Part 27 certificated rotorcraft.........            33.3            44.4
Part 29 certificated rotorcraft.........            17.7            88.6
                                         -----------------
    Total estimated benefits............           $88.1        $3,940.4
------------------------------------------------------------------------

    Following FAA's rationale as stated in the cost section earlier, 
column one (the base case) in the benefits table above shows 
incremental benefits of $88.1 million resulting from averted accidents 
in future compliant parts 23/27/29 aircraft; part 25 airplanes already 
meet similar JAA standards, hence no additional benefits attributable 
to part 25 airplanes accrue to society. Column two in the table 
presents the regulatory case; it shows the additional benefits 
associated with going from industry's self-determined protection 
standards (or current special conditions) to the NPRM's HIRF standards. 
Total regulatory incremental benefits equal $3,940.4 million and 
represent the value of avoiding the following numbers of accidents over 
the 34-year analysis period: (1) Part 23 airplanes, 24 accidents; (2) 
part 25 airplanes, 22 accidents; (3) part 27 rotorcraft, 41 accidents, 
and (4) part 29 rotorcraft, 14 accidents. The FAA believes that, based 
on the aforementioned risk assessment (by EMA Electro Magnetic 
Applications, Inc.), this would be the potential result absent the 
proposed standards if all airplanes certificated under part 25, the 
majority of aircraft certificated under parts 23 and 29, and a sizeable 
minority of part 27 rotorcraft, currently or in the future did not meet 
the JAA/EASA HIRF requirements (i.e., equivalent to those in the NPRM).

Summary of Costs and Benefits

    The incremental costs of meeting the NPRM requirements versus 
current industry practice equal $28.6 million and the associated 
benefits are $88.1 million, for a benefit-to-cost ratio of 3.1 to 1. 
Alternatively, the incremental costs of meeting the NPRM requirements 
versus current U.S. special conditions equal $409.5 million and the 
benefits are $3,940.4 million, for a benefit-to-cost ratio of 9.6 to 1. 
From either perspective, the proposed rule is clearly cost-beneficial.

Regulatory Flexibility Determination

    The Regulatory Flexibility Act of 1980 (RFA) establishes ``as a 
principle of regulatory issuance that agencies shall endeavor, 
consistent with the objective of the rule and of applicable statutes, 
to fit regulatory and informational requirements to the scale of the 
business, organizations, and governmental jurisdictions subject to 
regulation.'' To achieve that principle, the Act requires agencies to 
solicit and consider flexible regulatory proposals and to explain the 
rationale for their actions. The Act covers a wide-range of small 
entities, including small businesses, not-for-profit organizations and 
small governmental jurisdictions.
    Agencies must perform a review to determine whether a rulemaking 
action will have a significant economic impact on a substantial number 
of small entities. If an agency determines that it will, the agency 
must prepare a regulatory flexibility analysis as described in the Act. 
However, if an agency determines that a proposed or final rule is not 
expected to have a significant economic impact on a substantial number 
of small entities, section 605(b) of the 1980 act provides that the 
head of the agency may so certify and a regulatory flexibility analysis 
is not required. The certification must include a statement providing 
the factual basis for this determination, and the reasoning should be 
clear.
    The proposed rule would affect manufacturers of parts 23, 25, 27, 
and 29 aircraft produced under future new type-certificates. For 
manufacturers, a small entity is one with 1,500 or fewer employees. 
None of the part 25 or part 29 manufacturers has 1,500 or fewer 
employees; consequently, none is considered a small entity. There are, 
however, currently about four part 27 (utility rotorcraft) and ten part 
23 (small non-transport category airplanes) manufacturers, who have 
fewer than 1,500 employees and are considered small entities.
    With respect to the part 27 entities, the incremental costs of this 
NPRM are estimated at $875 per new-production rotorcraft. Part 27 
rotorcraft at the small

[[Page 5562]]

end generally sell for about $200,000; thus the incremental cost would 
represent only a fraction of one percent of each unit's sales price and 
clearly less than one percent of the typical small manufacturer's 
annual revenues. Consequently, the FAA does not consider the 
incremental cost to constitute a significant economic impact. Further, 
most utility rotorcraft are engaged in specialized activities such as 
logging, offshore oil drilling, construction, etc., the demand for 
which is highly price-inelastic; the manufacturers can readily pass on 
the relatively low incremental costs to purchasers of these highly-
specialized rotorcraft.
    The FAA contacted the ten part 23 small airframe manufacturers 
actively producing airplanes. The majority of these manufacture piston-
engine airplanes, most of which do not include sophisticated electrical 
systems. Six of the ten companies are in the initial stages of 
developing new airplane models that will include full-authority-
digital-engine-controls (FADEC). About one-half of these, however, 
could not yet estimate new development costs. One manufacturer, 
sufficiently into the pre-certification process, did provide estimates 
of incremental costs related to the FADECs (costs were based on data 
received from the engine supplier). Additional non-recurring design/
testing costs for engines in the new model would total $170,000 
(recurring costs were not specified and thus assumed not significant). 
Annualizing the cost at 7% over a 10-year production period equals 
$24,200. The company expects to produce 100 airplanes annually, each 
selling for $130,000; expected annual sales revenue therefore equals 
$13,000,000. Thus, the $24,200 total annual incremental cost 
attributable to HIRF represents less than two-tenths of one percent of 
annual sales ($24,200/$13,000,000), which the FAA believes does not 
constitute a significant economic impact.
    Two other small airframe manufacturers were contacted for similar 
cost data. When the FAA determined that the engine supplier in both 
cases was the same company referred to in the previous paragraph, that 
supplier was queried in order to save time. The incremental costs 
associated with HIRF-testing were similar, but less, than those 
estimated in the first case described, i.e., ranging from $120,000 to 
$140,000 per type certification. Annualizing the upper-end estimate of 
$140,000 at 7% over a 10-year production run equates to about $20,000. 
At a selling price of $130,000 per airplane (see first example above) 
and sales of 100 units annually, the $20,000 total annual incremental 
cost attributable to HIRF is between one-tenth/two-tenths of one 
percent of annual sales ($20,000/$13,000,000), which does not 
constitute a significant economic impact.
    Based on there being no small manufacturers of part 25 or part 29 
aircraft, and based on the described expense/revenue relationships for 
the part 23 and part 27 small manufacturers, the FAA certifies that 
this proposed rule would not have a significant economic impact on a 
substantial number of small entities. The FAA invites comments on the 
estimated small entity impact from interested and affected parties.

International Trade Impact Assessment

    The Trade Agreements Act of 1979 prohibits Federal agencies from 
engaging in any standards or related activities that create unnecessary 
obstacles to the foreign commerce of the United States. Legitimate 
domestic objectives, such as safety, are not considered unnecessary 
obstacles. The statute also requires consideration of international 
standards and where appropriate, that they be the basis for U.S. 
standards.
    In accordance with the above statute, the FAA has assessed the 
potential effect of this proposed rule for aircraft produced under the 
affected parts. This rulemaking is consistent with the Trade Agreements 
Act in that it adopts international standards as the basis of U.S. 
standards.

Unfunded Mandates Reform Act

    The Unfunded Mandates Reform Act of 1995 (the Act) is intended, 
among other things, to curb the practice of imposing unfunded Federal 
mandates on State, local, and tribal governments. Title II of the Act 
requires each Federal agency to prepare a written statement assessing 
the effects of any Federal mandate in a proposed or final agency rule 
that may result in an expenditure of $100 million or more (adjusted 
annually for inflation) in any one year by State, local, and tribal 
governments, in the aggregate, or by the private sector; such a mandate 
is deemed to be a ``significant regulatory action.'' The FAA currently 
uses an inflation-adjusted value of $120.7 million in lieu of $100 
million. This proposed rule does not contain such a mandate. The 
requirements of Title II do not apply.

Environmental Analysis

    FAA Order 1050.1E identifies FAA actions that are categorically 
excluded from preparation of an environmental assessment or 
environmental impact statement under the National Environmental Policy 
Act in the absence of extraordinary circumstances. The FAA has 
determined this proposed rulemaking action qualifies for the 
categorical exclusion identified in paragraph 308(c)(1) and involves no 
extraordinary circumstances.

Executive Order 13132, Federalism

    The FAA has analyzed this NPRM under the principles and criteria of 
Executive Order 13132, Federalism. We have determined that this action 
would not have a substantial direct affect on the States, on the 
relationship between the national Government and the States, or on the 
distribution of power and responsibilities among the various levels of 
government, and therefore would not have federalism implications.

Plain English

    Executive Order 12866 (58 FR 51735, Oct. 4, 1993) requires each 
agency to write regulations that are simple and easy to understand. We 
invite your comments on how to make these proposed regulations easier 
to understand, including answers to questions such as the following:
     Are the requirements in the proposed regulations clearly 
stated?
     Do the proposed regulations contain unnecessary technical 
language or jargon that interferes with their clarity?
     Would the regulations be easier to understand if they were 
divided into more (but shorter) sections?
     Is the description in the preamble helpful in 
understanding the proposed regulations?
    Please send your comments to the address specified in the ADDRESSES 
section.

Regulations That Significantly Affect Energy Supply, Distribution, or 
Use

    The FAA has analyzed this NPRM under Executive Order 13211, Actions 
Concerning Regulations that Significantly Affect Energy Supply, 
Distribution, or Use (May 18, 2001). We have determined that it is not 
a ``significant energy action'' under the executive order because it is 
not a ``significant regulatory action'' under Executive Order 12866, 
and it is not likely to have a significant adverse effect on the 
supply, distribution, or use of energy.

List of Subjects

14 CFR Part 23

    Air transportation, Aircraft, Aviation safety, Certification, 
Safety.

[[Page 5563]]

14 CFR Part 25

    Air transportation, Aircraft, Aviation safety, Certification, 
Safety.

14 CFR Part 27

    Air transportation, Aircraft, Aviation safety, Certification, 
Rotorcraft, Safety.

14 CFR Part 29

    Air transportation, Aircraft, Aviation safety, Certification, 
Rotorcraft, Safety.

The Proposed Amendment

    In consideration of the foregoing, the Federal Aviation 
Administration proposes to amend parts 23, 25, 27, and 29 of Title 14, 
Code of Federal Regulations (14 CFR) as follows:

PART 23--AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND 
COMMUTER CATEGORY AIRPLANES

    1. The authority citation for part 23 continues to read as follows:

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

    2. Add Sec.  23.1308 to subpart F to read as follows:


Sec.  23.1308  High-intensity Radiated Fields (HIRF) Protection.

    (a) Each electrical and electronic system that performs a function 
whose failure would prevent the continued safe flight and landing of 
the airplane must be designed and installed so that--
    (1) The function is not adversely affected during and after the 
time the airplane is exposed to HIRF environment I, as described in 
appendix J to this part;
    (2) The system automatically recovers normal operation, in a timely 
manner, after the airplane is exposed to HIRF environment I, as 
described in appendix J to this part, unless the system's recovery 
conflicts with other operational or functional requirements of the 
system; and
    (3) The system is not adversely affected during and after the time 
the airplane is exposed to HIRF environment II, as described in 
appendix J to this part.
    (b) Each electrical and electronic system that performs a function 
whose failure would significantly reduce the capability of the airplane 
or the ability of the flightcrew to respond to an adverse operating 
condition must be designed and installed so the system is not adversely 
affected when the equipment providing the function is exposed to 
equipment HIRF test level 1, 2, or 3, as described in appendix J to 
this part.
    (c) Each electrical and electronic system that performs a function 
whose failure would reduce the capability of the airplane or the 
ability of the flightcrew to respond to an adverse operating condition 
must be designed and installed so the system is not adversely affected 
when the equipment providing the function is exposed to equipment HIRF 
test level 4, as described in appendix J to this part.
    3. Add appendix J to part 23 to read as follows:

Appendix J to Part 23--HIRF Environments and Equipment HIRF Test Levels

    This appendix specifies the HIRF environments and equipment HIRF 
test levels for electrical and electronic systems under Sec.  23.1308. 
The field strength values for the HIRF environments and equipment HIRF 
test levels are expressed in root-mean-square units measured during the 
peak of the modulation cycle.
    (a) HIRF environment I is specified in the following table:

                      Table I.--HIRF Environment I
------------------------------------------------------------------------
                                                       Field strength
                                                        (volts/meter)
             Frequency (cycles/second)             ---------------------
                                                       Peak     Average
------------------------------------------------------------------------
10 kHz-2 MHz......................................         50         50
2 MHz-30 MHz......................................        100        100
30 MHz-100 MHz....................................         50         50
100 MHz-400 MHz...................................        100        100
400 MHz-700 MHz...................................        700         50
700 MHz-1 GHz.....................................        700        100
1 GHz-2 GHz.......................................      2,000        200
2 GHz-6 GHz.......................................      3,000        200
6 GHz-8 GHz.......................................      1,000        200
8 GHz-12 GHz......................................      3,000        300
12 GHz-18 GHz.....................................      2,000        200
18 GHz-40 GHz.....................................        600        200
------------------------------------------------------------------------

    (b) HIRF environment II is specified in the following table:

                     Table II.--HIRF Environment II
------------------------------------------------------------------------
                                                       Field strength
                                                        (volts/meter)
             Frequency (cycles/second)             ---------------------
                                                       Peak     Average
------------------------------------------------------------------------
10 kHz-500 kHz....................................         20         20
500 kHz-2 MHz.....................................         30         30
2 MHz-30 MHz......................................        100        100
30 MHz-100 MHz....................................         10         10
100 MHz-200 MHz...................................         30         10
200 MHz-400 MHz...................................         10         10
400 MHz-1 GHz.....................................        700         40
1 GHz-2 GHz.......................................      1,300        160
2 GHz-4 GHz.......................................      3,000        120
4 GHz-6 GHz.......................................      3,000        160
6 GHz-8 GHz.......................................        400        170
8 GHz-12 GHz......................................      1,230        230
12 GHz-18 GHz.....................................        730        190
18 GHz-40 GHz.....................................        600        150
------------------------------------------------------------------------

    (c) Equipment HIRF Test Level 1. (1) From 10 kilohertz (kHz) to 400 
megahertz (MHz), use conducted susceptibility tests with continuous 
wave (CW) and 1 kHz square wave modulation with 90 percent depth or 
greater. The conducted susceptibility current must start at a minimum 
of 0.6 milliamperes (mA) at 10 kHz, increasing 20 decibels (dB) per 
frequency decade to a minimum of 30 mA at 500 kHz.
    (2) From 500 kHz to 400 MHz, the conducted susceptibility current 
must be at least 30 mA.
    (3) From 100 MHz to 400 MHz, use radiated susceptibility tests at a 
minimum of 20 volts per meter (V/m) peak, with CW and 1 kHz square wave 
modulation with 90 percent depth or greater.
    (4) From 400 MHz to 8 gigahertz (GHz), use radiated susceptibility 
tests at a minimum of 150 V/m peak with pulse modulation of 0.1 percent 
duty cycle with 1 kHz pulse repetition frequency. This signal must be 
switched on and off at a rate of 1 Hz with a duty cycle of 50 percent.
    (5) From 400 MHz to 8 GHz, use radiated susceptibility tests at a 
minimum of 28 V/m peak with 1 kHz square wave modulation with 90 
percent depth or greater. This signal must be switched on and off at a 
rate of 1 Hz with a duty cycle of 50 percent.
    (d) Equipment HIRF Test Level 2. (1) From 10 kHz to 400 MHz, use 
conducted susceptibility tests with CW and 1 kHz square wave modulation 
with 90 percent depth or greater. The conducted susceptibility current 
must start at a minimum of 0.6 mA at 10 kHz, increasing 20 dB per 
frequency decade to a minimum of 30 mA at 500 kHz.
    (2) From 500 kHz to 400 MHz, the conducted susceptibility current 
must be at least 30 mA.
    (3) From 100 MHz to 400 MHz, use radiated susceptibility tests at a 
minimum of 20 V/m peak with CW and 1 kHz square wave modulation with 90 
percent depth or greater.
    (4) From 400 MHz to 8 GHz, use radiated susceptibility tests at a 
minimum of 150 V/m peak with pulse modulation of 4 percent duty cycle 
with a 1 kHz pulse repetition frequency. This signal must be switched 
on and off at a rate of 1 Hz with a duty cycle of 50 percent.
    (e) Equipment HIRF Test Level 3. Test level 3 is HIRF environment 
II in table II of this appendix reduced by acceptable aircraft transfer 
function and attenuation curves. Testing must cover the frequency band 
of 10 kHz to 8 GHz.
    (f) Equipment HIRF Test Level 4. (1) From 10 kHz to 400 MHz, use 
conducted susceptibility tests, starting

[[Page 5564]]

at a minimum of 0.15 mA at 10 kHz, increasing 20 dB per frequency 
decade to a minimum of 7.5 mA at 500 kHz.
    (2) From 500 kHz to 400 MHz, use conducted susceptibility tests at 
a minimum of 7.5 mA.
    (3) From 100 MHz to 8 GHz, use radiated susceptibility tests at a 
minimum of 5 V/m.

PART 25--AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES

    4. The authority citation for part 25 continues to read as follows:

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

    5. Add Sec.  25.1317 to subpart F to read as follows:


Sec.  25.1317  High-intensity Radiated Fields (HIRF) Protection.

    (a) Each electrical and electronic system that performs a function 
whose failure would prevent the continued safe flight and landing of 
the airplane must be designed and installed so that--
    (1) The function is not adversely affected during and after the 
time the airplane is exposed to HIRF environment I, as described in 
appendix K to this part;
    (2) The system automatically recovers normal operation, in a timely 
manner, after the airplane is exposed to HIRF environment I, as 
described in appendix K to this part, unless the system's recovery 
conflicts with other operational or functional requirements of the 
system; and
    (3) The system is not adversely affected during and after the time 
the airplane is exposed to HIRF environment II, as described in 
appendix K to this part.
    (b) Each electrical and electronic system that performs a function 
whose failure would significantly reduce the capability of the airplane 
or the ability of the flightcrew to respond to an adverse operating 
condition must be designed and installed so the system is not adversely 
affected when the equipment providing these functions is exposed to 
equipment HIRF test level 1, 2, or 3, as described in appendix K to 
this part.
    (c) Each electrical and electronic system that performs a function 
whose failure would reduce the capability of the airplane or the 
ability of the flightcrew to respond to an adverse operating condition 
must be designed and installed so the system is not adversely affected 
when the equipment providing the function is exposed to equipment HIRF 
test level 4, as described in appendix K to this part.
    6. Add appendix K to part 25 to read as follows:

Appendix K to Part 25--HIRF Environments and Equipment HIRF Test Levels

    This appendix specifies the HIRF environments and equipment HIRF 
test levels for electrical and electronic systems under Sec.  25.1317. 
The field strength values for the HIRF environments and equipment HIRF 
test levels are expressed in root-mean-square units measured during the 
peak of the modulation cycle.
    (a) HIRF environment I is specified in the following table:

                      Table I.--HIRF Environment I
------------------------------------------------------------------------
                                                       Field strength
                                                        (volts/meter)
            Frequency  (cycles/second)             ---------------------
                                                       Peak     Average
------------------------------------------------------------------------
10 kHz-2 MHz......................................         50         50
2 MHz-30 MHz......................................        100        100
30 MHz-100 MHz....................................         50         50
100 MHz-400 MHz...................................        100        100
400 MHz-700 MHz...................................        700         50
700 MHz-1 GHz.....................................        700        100
1 GHz-2 GHz.......................................      2,000        200
2 GHz-6 GHz.......................................      3,000        200
6 GHz-8 GHz.......................................      1,000        200
8 GHz-12 GHz......................................      3,000        300
12 GHz-18 GHz.....................................      2,000        200
18 GHz-40 GHz.....................................        600        200
------------------------------------------------------------------------

    (b) HIRF environment II is specified in the following table:

                     Table II.--HIRF Environment II
------------------------------------------------------------------------
                                                       Field strength
                                                        (volts/meter)
            Frequency  (cycles/second)             ---------------------
                                                       Peak     Average
------------------------------------------------------------------------
10 kHz-500 kHz....................................         20         20
500 kHz-2 MHz.....................................         30         30
2 MHz-30 MHz......................................        100        100
30 MHz-100 MHz....................................         10         10
100 MHz-200 MHz...................................         30         10
200 MHz-400 MHz...................................         10         10
400 MHz-1 GHz.....................................        700         40
1 GHz-2 GHz.......................................      1,300        160
2 GHz-4 GHz.......................................      3,000        120
4 GHz-6 GHz.......................................      3,000        160
6 GHz-8 GHz.......................................        400        170
8 GHz-12 GHz......................................      1,230        230
12 GHz-18 GHz.....................................        730        190
18 GHz-40 GHz.....................................        600        150
------------------------------------------------------------------------

    (c) Equipment HIRF Test Level 1. (1) From 10 kilohertz (kHz) to 400 
megahertz (MHz), use conducted susceptibility tests with continuous 
wave (CW) and 1 kHz square wave modulation with 90 percent depth or 
greater. The conducted susceptibility current must start at a minimum 
of 0.6 milliamperes (mA) at 10 kHz, increasing 20 decibels (dB) per 
frequency decade to a minimum of 30 mA at 500 kHz.
    (2) From 500 kHz to 400 MHz, the conducted susceptibility current 
must be at least 30 mA.
    (3) From 100 MHz to 400 MHz, use radiated susceptibility tests at a 
minimum of 20 volts per meter (V/m) peak with CW and 1 kHz square wave 
modulation with 90 percent depth or greater.
    (4) From 400 MHz to 8 gigahertz (GHz), use radiated susceptibility 
tests at a minimum of 150 V/m peak with pulse modulation of 0.1 percent 
duty cycle with 1 kHz pulse repetition frequency. This signal must be 
switched on and off at a rate of 1 Hz with a duty cycle of 50 percent.
    (5) From 400 MHz to 8 GHz, use radiated susceptibility tests at a 
minimum of 28 V/m peak with 1 kHz square wave modulation with 90 
percent depth or greater. This signal must be switched on and off at a 
rate of 1 Hz with a duty cycle of 50 percent.
    (d) Equipment HIRF Test Level 2. (1) From 10 kHz to 400 MHz, use 
conducted susceptibility tests with CW and 1 kHz square wave modulation 
with 90 percent depth or greater. The conducted susceptibility current 
must start at a minimum of 0.6 mA at 10 kHz, increasing 20 dB per 
frequency decade to a minimum of 30 mA at 500 kHz.
    (2) From 500 kHz to 400 MHz, the conducted susceptibility current 
must be at least 30 mA.
    (3) From 100 MHz to 400 MHz, use radiated susceptibility tests at a 
minimum of 20 V/m peak with CW and 1 kHz square wave modulation with 90 
percent depth or greater.
    (4) From 400 MHz to 8 GHz, use radiated susceptibility tests at a 
minimum of 150 V/m peak with pulse modulation of 4 percent duty cycle 
with a 1 kHz pulse repetition frequency. This signal must be switched 
on and off at a rate of 1 Hz with a duty cycle of 50 percent.
    (e) Equipment HIRF Test Level 3. Test level 3 is HIRF environment 
II in table II of this appendix reduced by acceptable aircraft transfer 
function and attenuation curves. Testing must cover the frequency band 
of 10 kHz to 8 GHz.
    (f) Equipment HIRF Test Level 4. (1) From 10 kHz to 400 MHz, use 
conducted susceptibility tests, starting at a minimum of 0.15 mA at 10 
kHz, increasing 20 dB per frequency decade to a minimum of 7.5 mA at 
500 kHz.
    (2) From 500 kHz to 400 MHz, use conducted susceptibility tests at 
a minimum of 7.5 mA.

[[Page 5565]]

    (3) From 100 MHz to 8 GHz, use radiated susceptibility tests at a 
minimum of 5 V/m.

PART 27--AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT

    7. The authority citation for part 27 continues to read as follows:

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

    8. Add Sec.  27.1317 to subpart F to read as follows:


Sec.  27.1317  High-intensity Radiated Fields (HIRF) Protection.

    (a) Each electrical and electronic system that performs a function 
whose failure would prevent the continued safe flight and landing of 
the rotorcraft must be designed and installed so that--
    (1) The function is not adversely affected during and after the 
time the rotorcraft is exposed to HIRF environment I, as described in 
appendix D to this part;
    (2) The system automatically recovers normal operation, in a timely 
manner, after the rotorcraft is exposed to HIRF environment I, as 
described in appendix D to this part, unless this conflicts with other 
operational or functional requirements of that system;
    (3) The system is not adversely affected during and after the time 
the rotorcraft is exposed to HIRF environment II, as described in 
appendix D to this part; and
    (4) Each function required during operation under visual flight 
rules is not adversely affected during and after the time the 
rotorcraft is exposed to HIRF environment III, as described in appendix 
D to this part.
    (b) Each electrical and electronic system that performs a function 
whose failure would significantly reduce the capability of the 
rotorcraft or the ability of the flightcrew to respond to an adverse 
operating condition must be designed and installed so the system is not 
adversely affected when the equipment providing these functions is 
exposed to equipment HIRF test level 1, 2, or 3, as described in 
appendix D to this part.
    (c) Each electrical and electronic system that performs a function 
whose failure would reduce the capability of the rotorcraft or the 
ability of the flightcrew to respond to an adverse operating condition, 
must be designed and installed so the system is not adversely affected 
when the equipment providing these functions is exposed to equipment 
HIRF test level 4, as described in appendix D to this part.
    9. Add appendix D to part 27 to read as follows:

Appendix D to Part 27--HIRF Environments and Equipment HIRF Test Levels

    This appendix specifies the HIRF environments and equipment HIRF 
test levels for electrical and electronic systems under Sec.  27.1317. 
The field strength values for the HIRF environments and laboratory 
equipment HIRF test levels are expressed in root-mean-square units 
measured during the peak of the modulation cycle.
    (a) HIRF environment I is specified in the following table:

                      Table I.--HIRF Environment I
------------------------------------------------------------------------
                                                       Field strength
                                                        (volts/meter)
            Frequency  (cycles/second)             ---------------------
                                                       Peak     Average
------------------------------------------------------------------------
10 kHz-2 MHz......................................         50         50
2 MHz-30 MHz......................................        100        100
30 MHz-100 MHz....................................         50         50
100 MHz-400 MHz...................................        100        100
400 MHz-700 MHz...................................        700         50
700 MHz-1 GHz.....................................        700        100
1 GHz-2 GHz.......................................      2,000        200
2 GHz-6 GHz.......................................      3,000        200
6 GHz-8 GHz.......................................      1,000        200
8 GHz-12 GHz......................................      3,000        300
12 GHz-18 GHz.....................................      2,000        200
18 GHz-40 GHz.....................................        600        200
------------------------------------------------------------------------

    (b) HIRF environment II is specified in the following table:

                     Table II.--HIRF Environment II
------------------------------------------------------------------------
                                                    Field Srength (Volts/
                                                           Meter)
            Frequency  (cycles/second)             ---------------------
                                                       Peak     Average
------------------------------------------------------------------------
10 kHz-500 kHz....................................         20         20
500 kHz-2 MHz.....................................         30         30
2 MHz-30 MHz......................................        100        100
30 MHz-100 MHz....................................         10         10
100 MHz-200 MHz...................................         30         10
200 MHz-400 MHz...................................         10         10
400 MHz-1 GHz.....................................        700         40
1 GHz-2 GHz.......................................      1,300        160
2 GHz-4 GHz.......................................      3,000        120
4 GHz-6 GHz.......................................      3,000        160
6 GHz-8 GHz.......................................        400        170
8 GHz-12 GHz......................................      1,230        230
12 GHz-18 GHz.....................................        730        190
18 GHz-40 GHz.....................................        600        150
------------------------------------------------------------------------

    (c) HIRF environment III is specified in the following table:

                    Table III.--HIRF Environment III
------------------------------------------------------------------------
                                                       Field strength
                                                        (volts/meter)
            Frequency  (cycles/second)             ---------------------
                                                       Peak     Average
------------------------------------------------------------------------
10 kHz-100 kHz....................................        150        150
100 kHz-400 MHz...................................        200        200
400 MHz-700 MHz...................................        730        200
700 MHz-1 GHz.....................................      1,400        240
1 GHz-2 GHz.......................................      5,000        250
2 GHz-4 GHz.......................................      6,000        490
4 GHz-6 GHz.......................................      7,200        400
6 GHz-8 GHz.......................................      1,100        170
8 GHz-12 GHz......................................      5,000        330
12 GHz-18 GHz.....................................      2,000        330
18 GHz-40 GHz.....................................      1,000        420
------------------------------------------------------------------------

    (d) Equipment HIRF Test Level 1. (1) From 10 kilohertz (kHz) to 400 
megahertz (MHz), use conducted susceptibility tests with continuous 
wave (CW) and 1 kHz square wave modulation with 90 percent depth or 
greater. The conducted susceptibility current must start at a minimum 
of 0.6 milliamperes (mA) at 10 kHz, increasing 20 decibels (dB) per 
frequency decade to a minimum of 30 mA at 500 kHz.
    (2) From 500 kHz to 400 MHz, the conducted susceptibility current 
must be at least 30 mA.
    (3) From 100 MHz to 400 MHz, use radiated susceptibility tests at a 
minimum of 20 volts per meter (V/m) peak with CW and 1 kHz square wave 
modulation with 90 percent depth or greater.
    (4) From 400 MHz to 8 gigahertz (GHz), use radiated susceptibility 
tests at a minimum of 150 V/m peak with pulse modulation of 0.1 percent 
duty cycle with 1 kHz pulse repetition frequency. This signal must be 
switched on and off at a rate of 1 Hz with a duty cycle of 50 percent.
    (5) From 400 MHz to 8 GHz, use radiated susceptibility tests at a 
minimum of 28 V/m peak with 1 kHz square wave modulation with 90 
percent depth or greater. This signal must be switched on and off at a 
rate of 1 Hz with a duty cycle of 50 percent.
    (e) Equipment HIRF Test Level 2. (1) From 10 kHz to 400 MHz, use 
conducted susceptibility tests with CW and 1 kHz square wave modulation 
with 90 percent depth or greater. The conducted susceptibility current 
must start at a minimum of 0.6 mA at 10 kHz, increasing 20 dB per 
frequency decade to a minimum of 30 mA at 500 kHz.
    (2) From 500 kHz to 400 MHz, the conducted susceptibility current 
must be at least 30 mA.
    (3) From 100 MHz to 400 MHz, use radiated susceptibility tests at a 
minimum of 20 V/m peak with CW and 1 kHz square wave modulation with 90 
percent depth or greater.

[[Page 5566]]

    (4) From 400 MHz to 8 GHz, use radiated susceptibility tests at a 
minimum of 150 V/m peak with pulse modulation of 4 percent duty cycle 
with a 1 kHz pulse repetition frequency. This signal must be switched 
on and off at a rate of 1 Hz with a duty cycle of 50 percent.
    (f) Equipment HIRF Test Level 3. Test level 3 is HIRF environment 
II in table II of this appendix reduced by acceptable aircraft transfer 
function and attenuation curves. Testing must cover the frequency band 
of 10 kHz to 8 GHz.
    (g) Equipment HIRF Test Level 4. (1) From 10 kHz to 400 MHz, use 
conducted susceptibility tests, starting at a minimum of 0.15 mA at 10 
kHz, increasing 20 dB per frequency decade to a minimum of 7.5 mA at 
500 kHz.
    (2) From 500 kHz to 400 MHz, use conducted susceptibility tests at 
a minimum of 7.5 mA.
    (3) From 100 MHz to 8 GHz, use radiated susceptibility tests at a 
minimum of 5 V/m.

PART 29--AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT

    10. The authority citation for part 29 continues to read as 
follows:

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

    11. Add Sec.  29.1317 to subpart F to read as follows:


Sec.  29.1317  High-intensity Radiated Fields (HIRF) Protection.

    (a) Each electrical and electronic system that performs a function 
whose failure would prevent the continued safe flight and landing of 
the rotorcraft must be designed and installed so that--
    (1) The function is not adversely affected during and after the 
time the rotorcraft is exposed to HIRF environment I, as described in 
appendix E to this part;
    (2) The system automatically recovers normal operation, in a timely 
manner, after the rotorcraft is exposed to HIRF environment I, as 
described in appendix E to this part, unless this conflicts with other 
operational or functional requirements of that system;
    (3) The system is not adversely affected during and after the time 
the rotorcraft is exposed to HIRF environment II, as described in 
appendix E to this part; and
    (4) Each function required during operation under visual flight 
rules is not adversely affected during and after the time the 
rotorcraft is exposed to HIRF environment III, as described in appendix 
E to this part.
    (b) Each electrical and electronic system that performs a function 
whose failure would significantly reduce the capability of the 
rotorcraft or the ability of the flightcrew to respond to an adverse 
operating condition must be designed and installed so the system is not 
adversely affected when the equipment providing these functions is 
exposed to equipment HIRF test level 1, 2, or 3, as described in 
appendix E to this part.
    (c) Each electrical and electronic system that performs such a 
function whose failure would reduce the capability of the rotorcraft or 
the ability of the flightcrew to respond to an adverse operating 
condition must be designed and installed so the system is not adversely 
affected when the equipment providing these functions is exposed to 
equipment HIRF test level 4, as described in appendix E to this part.
    12. Add appendix E to part 29 to read as follows:

Appendix E to Part 29--HIRF Environments and Equipment HIRF Test Levels

    This appendix specifies the HIRF environments and equipment HIRF 
test levels for electrical and electronic systems under Sec.  29.1317. 
The field strength values for the HIRF environments and laboratory 
equipment HIRF test levels are expressed in root-mean-square units 
measured during the peak of the modulation cycle.
    (a) HIRF environment I is specified in the following table:

                      Table I.--HIRF Environment I
------------------------------------------------------------------------
                                                       Field strength
                                                        (volts/meter)
             Frequency (cycles/second)             ---------------------
                                                       Peak     Average
------------------------------------------------------------------------
10 kHz-2 MHz......................................         50         50
2 MHz-30 MHz......................................        100        100
30 MHz-100 MHz....................................         50         50
100 MHz-400 MHz...................................        100        100
400 MHz-700 MHz...................................        700         50
700 MHz-1 GHz.....................................        700        100
1 GHz-2 GHz.......................................      2,000        200
2 GHz-6 GHz.......................................      3,000        200
6 GHz-8 GHz.......................................      1,000        200
8 GHz-12 GHz......................................      3,000        300
12 GHz-18 GHz.....................................      2,000        200
18 GHz-40 GHz.....................................        600        200
------------------------------------------------------------------------

    (b) HIRF environment II is specified in the following table:

                     Table II.--HIRF Environment II
------------------------------------------------------------------------
                                                       Field strength
                                                        (volts/meter)
             Frequency (cycles/second)             ---------------------
                                                       Peak     Average
------------------------------------------------------------------------
10 kHz-500 kHz....................................         20         20
500 kHz-2 MHz.....................................         30         30
2 MHz-30 MHz......................................        100        100
30 MHz-100 MHz....................................         10         10
100 MHz-200 MHz...................................         30         10
200 MHz-400 MHz...................................         10         10
400 MHz-1 GHz.....................................        700         40
1 GHz-2 GHz.......................................      1,300        160
2 GHz-4 GHz.......................................      3,000        120
4 GHz-6 GHz.......................................      3,000        160
6 GHz-8 GHz.......................................        400        170
8 GHz-12 GHz......................................      1,230        230
12 GHz-18 GHz.....................................        730        190
18 GHz-40 GHz.....................................        600        150
------------------------------------------------------------------------

    (c) HIRF environment III is specified in the following table:

                    Table III.-- HIRF Environment III
------------------------------------------------------------------------
                                                       Field strength
                                                        (volts/meter)
             Frequency (cycles/second)             ---------------------
                                                       Peak     Average
------------------------------------------------------------------------
10 kHz-100 kHz....................................        150        150
100 kHz-400 MHz...................................        200        200
400 MHz-700 MHz...................................        730        200
700 MHz-1 GHz.....................................      1,400        240
1 GHz-2 GHz.......................................      5,000        250
2 GHz-4 GHz.......................................      6,000        490
4 GHz-6 GHz.......................................      7,200        400
6 GHz-8 GHz.......................................      1,100        170
8 GHz-12 GHz......................................      5,000        330
12 GHz-18 GHz.....................................      2,000        330
18 GHz-40 GHz.....................................      1,000        420
------------------------------------------------------------------------

    (d) Equipment HIRF Test Level 1. (1) From 10 kilohertz (kHz) to 400 
megahertz (MHz), use conducted susceptibility tests with continuous 
wave (CW) and 1 kHz square wave modulation with 90 percent depth or 
greater. The conducted susceptibility current must start at a minimum 
of 0.6 milliamperes (mA) at 10 kHz, increasing 20 decibels (dB) per 
frequency decade to a minimum of 30 mA at 500 kHz.
    (2) From 500 kHz to 400 MHz, the conducted susceptibility current 
must be at least 30 mA.
    (3) From 100 MHz to 400 MHz, use radiated susceptibility tests at a 
minimum of 20 volts per meter (V/m) peak, with CW and 1 kHz square wave 
modulation with 90 percent depth or greater.
    (4) From 400 MHz to 8 gigahertz (GHz), use radiated susceptibility 
tests at a minimum of 150 V/m peak with pulse modulation of 0.1 percent 
duty cycle with 1 kHz pulse repetition frequency. This signal must be 
switched on and off at a rate of 1 Hz with a duty cycle of 50 percent.
    (5) From 400 MHz to 8 GHz, use radiated susceptibility tests at a

[[Page 5567]]

minimum of 28 V/m peak with 1 kHz square wave modulation with 90 
percent depth or greater. This signal must be switched on and off at a 
rate of 1 Hz with a duty cycle of 50 percent.
    (e) Equipment HIRF Test Level 2. (1) From 10 kHz to 400 MHz, use 
conducted susceptibility tests with CW and 1 kHz square wave modulation 
with 90 percent depth or greater. The conducted susceptibility current 
must start at a minimum of 0.6 mA at 10 kHz, increasing 20 dB per 
frequency decade to a minimum of 30 mA at 500 kHz.
    (2) From 500 kHz to 400 MHz, the conducted susceptibility current 
must be at least 30 mA.
    (3) From 100 MHz to 400 MHz, use radiated susceptibility tests at a 
minimum of 20 V/m peak with CW and 1 kHz square wave modulation with 90 
percent depth or greater.
    (4) From 400 MHz to 8 GHz, use radiated susceptibility tests at a 
minimum of 150 V/m peak with pulse modulation of 4 percent duty cycle 
with a 1 kHz pulse repetition frequency. This signal must be switched 
on and off at a rate of 1 Hz with a duty cycle of 50 percent.
    (f) Equipment HIRF Test Level 3. Test level 3 is HIRF environment 
II in table II of this appendix reduced by acceptable aircraft transfer 
function and attenuation curves. Testing must cover the frequency band 
of 10 kHz to 8 GHz.
    (g) Equipment HIRF Test Level 4. (1) From 10 kHz to 400 MHz, use 
conducted susceptibility tests, starting at a minimum of 0.15 mA at 10 
kHz, increasing 20 dB per frequency decade to a minimum of 7.5 mA at 
500 kHz.
    (2) From 500 kHz to 400 MHz, use conducted susceptibility tests at 
a minimum of 7.5 mA.
    (3) From 100 MHz to 8 GHz, use radiated susceptibility tests at a 
minimum of 5 V/m.

    Issued in Washington, DC, on January 25, 2006.
Dorenda D. Baker,
Acting Director, Aircraft Certification Service.
[FR Doc. 06-895 Filed 1-31-06; 8:45 am]
BILLING CODE 4910-13-P`