Document ID: FAA-2010-0224-0001
Agency: faa
Document Type: Rule
Title: Airworthiness Standards: Electrical and Electronic System Lightning Protection
Posted Date: 2010-04-02T04:00Z

[Federal Register: April 2, 2010 (Volume 75, Number 63)]
[Proposed Rules]               
[Page 16676-16683]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr02ap10-18]                         

========================================================================
Proposed Rules
                                                Federal Register
________________________________________________________________________

This section of the FEDERAL REGISTER contains notices to the public of 
the proposed issuance of rules and regulations. The purpose of these 
notices is to give interested persons an opportunity to participate in 
the rule making prior to the adoption of the final rules.

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[[Page 16676]]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Parts 23, 25, 27, and 29

[Docket No. FAA-2010-0224; Notice No. 10-05]
RIN 2120-AJ57

 
Airworthiness Standards; Electrical and Electronic System 
Lightning Protection

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: The Federal Aviation Administration (FAA) proposes to amend 
the lightning protection airworthiness standards by establishing new 
lightning protection regulations for electrical and electronic systems 
installed on aircraft certificated under parts 23, 27, and 29, and 
revising lightning protection regulations for electrical and electronic 
systems installed on airplanes certificated under part 25. The proposed 
rulemaking would establish two levels of lightning protection for 
aircraft systems based on consequences of system function failure: 
Catastrophic consequences which would prevent continued safe flight and 
landing and hazardous or major consequences which would reduce the 
capability of the aircraft or the ability of the flightcrew to respond 
to an adverse operating condition. The proposed rulemaking would also 
establish lightning protection for aircraft systems according to the 
aircraft's potential for lightning exposure. Compliance with the new 
requirements would be based on demonstration of effective lightning 
protection for electrical and electronic systems. The proposed 
airworthiness standards would establish consistent lightning protection 
requirements for electrical and electronic systems.

DATES: Send your comments on or before July 1, 2010.

ADDRESSES: You may send comments identified by Docket Number [Insert 
docket number, for example, FAA-200X-XXXXX] using any of the following 
methods:
     Federal eRulemaking Portal: Go to http://
www.regulations.gov and follow the online instructions for sending your 
comments electronically.
     Mail: Send comments to Docket Operations, M-30; U.S. 
Department of Transportation, 1200 New Jersey Avenue, SE., Room W12-
140, West Building Ground Floor, Washington, DC 20590-0001.
     Hand Delivery or Courier: Take comments to Docket 
Operations in Room W12-140 of the West Building Ground Floor at 1200 
New Jersey Avenue, SE., Washington, DC, between 9 a.m. and 5 p.m., 
Monday through Friday, except Federal holidays.
     Fax: Fax comments to Docket Operations at 202-493-2251.

For more information on the rulemaking process, see the SUPPLEMENTARY 
INFORMATION section of this document.
    Privacy: We will post all comments we receive, without change, to 
http://www.regulations.gov, including any personal information you 
provide. Using the search function of our docket Web site, anyone can 
find and read the electronic form of all comments received into any of 
our dockets, including the name of the individual sending the comment 
(or signing the comment for 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://DocketsInfo.dot.gov.
    Docket: To read background documents or comments received, go to 
http://www.regulations.gov at any time and follow the online 
instructions for accessing the docket or Docket Operations in Room W12-
140 of the West Building Ground Floor at 1200 New Jersey Avenue, SE., 
Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, 
except Federal holidays.

FOR FURTHER INFORMATION CONTACT: For technical questions concerning 
this proposed rule contact Lee Nguyen, AIR-130, Federal Aviation 
Administration, Suite 4102, 470 L'Enfant Plaza, Washington, DC 20591; 
telephone (202) 385-4676; facsimile (202) 385-4651, e-mail 
lee.nguyen@faa.gov. For legal questions concerning this proposed rule 
contact Viola Pando, AGC-220, Federal Aviation Administration, 800 
Independence Ave., SW., Washington, DC 20591; telephone (202) 493-5293; 
facsimile (202) 267-7971, e-mail viola.pando@faa.gov.

SUPPLEMENTARY INFORMATION: 
    Later in this preamble under the Additional Information section, we 
discuss how you can comment on this proposal and how we will handle 
your comments. Included in this discussion is related information about 
the docket, privacy, and the handling of proprietary or confidential 
business information. We also discuss how you can get a copy of related 
rulemaking documents.

Authority for This Rulemaking

    The FAA's authority to issue rules on aviation safety is found in 
Title 49 of the United States Code. Subtitle I, Section 106 describes 
the authority of the FAA Administrator. Subtitle VII, Aviation 
Programs, describes in more detail the scope of 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 with prescribing regulations 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 the effects of 
lightning, this regulation is within the scope of the Administrator's 
authority.

Background and History

    Existing regulations for lightning protection of electrical and 
electronic systems installed on aircraft certificated under 14 CFR 
parts 23, 27 and 29 require the type certification applicant only to 
``consider'' the effects of lightning. Unlike system lightning 
protection regulations for part 25 airplanes, these regulations have 
not been significantly amended since they were first adopted, and do 
not reflect current advances in technology.

A. History of Lightning Regulations

    In the 1960s, regulations applicable to lightning protection for 
aircraft design, construction, and fuel systems were adopted for 
aircraft certificated under

[[Page 16677]]

parts 23, 25, 27 and 29. The regulations required that the aircraft be 
protected against catastrophic effects of lightning, but did not have 
specific requirements for electrical and electronic system lightning 
protection. At the time, most aircraft were designed with mechanical 
systems, or simple electrical and electronic systems. Airframe 
components were made from aluminum materials, with high electrical 
conductivity, and offered good protection against lightning.
    The early 1980s ushered in part 25 transport airplane designs that 
routinely included more complex electrical and electronic systems. 
Flight-critical electronic primary flight controls, electronic primary 
flight displays, and full-authority electronic engine controls became 
common on transport airplanes certificated under part 25. At this time, 
the FAA began to impose lightning protection requirements for critical 
and essential electrical and electronic systems through special 
conditions, when appropriate, for part 25 airplane certification 
projects.
    As electrical and electronic systems became more common on part 25 
airplanes, the FAA issued Sec.  25.1316, specifically requiring 
protection for electrical and electronic systems on part 25 transport 
category airplanes. The final rule was published on April 28, 1994 (59 
FR 22112). This regulation, in effect today, requires lightning 
protection for electrical and electronic systems based on the 
consequences of failure for functions these systems perform. The 
present regulation provides specific considerations that the applicant 
must design for to validate that the electrical and electronic systems 
and functions are protected from the effects of lightning strikes.

B. Related Rulemaking Activity

    The FAA tasked the Aviation Rulemaking Advisory Committee (ARAC) on 
Transport Airplane and Engine Issues (57 FR 58843; December 11, 1992) 
to develop recommendations for specific electrical and electronic 
systems lightning protection requirements for aircraft certificated 
under parts 23, 27, and 29 standards.
    The ARAC submitted recommendations to the FAA in November 1998. The 
recommendations included lightning protection requirements, based on 
the consequences of the failure of system functions, similar to the 
requirements in Sec.  25.1316. The ARAC also recommended changes to 
Sec.  25.1316 consistent with its recommendations for classification of 
the failure conditions for parts 23, 27, and 29. ARAC recommended the 
same requirements for all four parts.
    The FAA considered the ARAC recommendations in developing this 
notice of proposed rulemaking (NPRM) and agrees with these 
recommendations, with one exception. After careful consideration, the 
FAA is unable to endorse the ARAC recommendation to provide an 
exception to the requirement for automatic and timely recovery of a 
system that performs a function for which failure is catastrophic. ARAC 
recommended an exception to recovery of such a system in instances 
where the recovery of the system would conflict with other operational 
or functional requirements of the system. We are unable to identify a 
situation where such an exception would be appropriate, nor could we 
justify the need for such an exception and propose requirements that 
could ensure an equivalent level of safety.
    The recommendations of the ARAC are available at the following Web 
address: http://www.faa.gov/regulations_policies/rulemaking/
committees/arac/issue_areas/tae/eeh/.

C. Advisory Material

    In the absence of performance standards for protection of 
electrical and electronic systems from lightning effects, the FAA has 
issued Advisory Circular (AC) 20-136A, ``Protection of Aircraft 
Electrical/Electronic System against the Indirect Effects of 
Lightning.'' Since advisory circulars are not mandatory, a type 
certificate applicant may elect to ignore or deviate from the guidance 
therein, while still satisfying the requirement to ``consider'' 
lightning. The lack of specific performance standards has resulted in a 
variety of different interpretations and means of compliance for system 
lightning protection.

General Discussion of the Proposal

    The proposed rulemaking would establish type certification 
standards for lightning protection of electrical and electronic systems 
for aircraft certificated under parts 23, 27 and 29. This action also 
proposes to revise Sec.  25.1316 for transport category airplanes to be 
consistent in format with the proposed regulations applicable to other 
aircraft.
    This rulemaking reflects a change in our approach to achieving 
lightning protection for aircraft by protecting functions of electrical 
and electronic systems. The current part 25 regulation for lightning 
protection focuses on protection of electrical and electronic systems 
that perform critical and essential functions and are no longer 
compatible or consistent with the latest classification concepts, 
terminology, and practices. Parts 23, 27 and 29 regulations for 
lightning protection are less precise, and require the applicant only 
to ``consider'' lightning. While the focus on protection of electrical 
and electronic systems that perform critical or essential functions was 
fundamental to the wording of earlier airworthiness standards regarding 
systems, and associated advisory circulars, this proposal focuses on 
the effects that failure conditions would have on aircraft safety. The 
FAA proposes that lightning protection design required for each 
aircraft would be determined by the type of electrical and electronic 
systems installed on the aircraft, and how critical the system or 
function is to either continued flight and landing, or the aircraft 
capability and flightcrew's ability to respond to adverse operating 
conditions.
    In aircraft, the term ``electrical and electronic system'' refers 
to the electrical and electronic equipment, associated software, and 
interconnecting wires installed on aircraft to perform one or more 
functions. The term ``function'' refers to the action that the system 
performs. An aircraft system may perform multiple functions with 
different failure conditions. For example, an engine control system may 
perform the function of the engine thrust control--for which failure 
could have catastrophic effects on the continued safe flight and 
landing of the aircraft. The engine control system may also perform the 
function of engine condition monitoring--for which failure could have 
hazardous or major effects on continued safe operation of the aircraft. 
A function may also be performed by multiple systems or subsystems. For 
example, the function of controlling engine thrust may be provided by 
an electronic engine control subsystem, with a separate backup 
mechanical control subsystem.

A. Proposed Performance Standards

    The proposed regulations would establish consistent performance 
standards to design lightning protection for those aircraft electrical 
and electronic systems that provide:
    1. Functions for which failure would prevent the continued safe 
flight and landing of the aircraft: Failure of these functions could 
result in catastrophic consequences such as loss of life and loss of 
the aircraft;
    2. Functions for which failure would reduce the capability of the 
aircraft or the ability of the flightcrew to cope with adverse 
operating conditions: Failure of

[[Page 16678]]

these functions could have hazardous or major consequences.
    This NPRM identifies system lightning performance standards for 
item 1 as ``protection against catastrophic failure.'' These standards 
are addressed by paragraph (a) of the proposed regulations. System 
lightning performance standards for item 2 will be referenced as 
``protection against hazardous or major failure.'' These standards are 
addressed by paragraph (b) of the proposed regulations.
    The proposed standards for protection against catastrophic failure 
would require an applicant to show that the function would not be 
adversely affected during or after the time the aircraft is exposed to 
lightning. Compliance with the standard would depend on the specific 
aircraft function, the system that performs that function, and the 
effects of failure on the system and function. Further guidance on 
defining the adverse effects for specific aircraft system functions can 
be found in various FAA advisory materials.
    The system could be affected during lightning exposure because a 
backup system continues to provide the function, even though the 
function may not be adversely affected. Accordingly, the applicant 
would be required to show that the system would automatically recover 
normal operation after the lightning exposure in a timely manner. 
``Normal operation'' means the ability of the system to perform 
functions to the extent necessary to continue safe flight and landing. 
For systems that provide one or more functions, the proposal would 
require the system to automatically recover normal operations of those 
functions for which failure could be catastrophic. Other functions 
would not be required to return to normal operation. The FAA would 
determine what constitutes ``timely'' automatic recovery on a case-by-
case evaluation, based on engineering judgment of the specific function 
and its failure effects.
    The aircraft engine thrust/power control is an example of a 
function for which failure would have catastrophic effects on the 
aircraft's ability to continue safe flight and landing. A full-
authority electronic engine control system may provide this function, 
and perform aircraft engine thrust/power control by automatically 
regulating fuel flow and airflow to the engine(s). The loss or 
malfunction of this function could stop the engines or result in engine 
overspeed, which could result in a catastrophic failure condition. In 
this situation, the applicant would be required to ensure the aircraft 
engine thrust/power control function is not adversely affected during 
or after lightning exposure.
    The aircraft display is another function for which failure would 
have catastrophic effects on continued safe flight and landing. This 
function provides aircraft attitude, altitude, and airspeed information 
to the pilot, which are required for continued safe flight and landing 
of the aircraft. The aircraft display may be provided by two systems: 
An electronic primary display and an electromechanical standby display. 
In this situation, the primary display may momentarily blank while the 
aircraft is exposed to lightning, provided the information is available 
from a standby display. The applicant would be required to demonstrate 
that the primary display system automatically recovers normal operation 
in a timely manner with no adverse effect on providing the attitude, 
altitude, and airspeed information.
    The proposed requirements for protection against hazardous or major 
failure would require the applicant to show that the system would not 
be damaged, and the function would recover normal operation in a timely 
manner after the aircraft is exposed to lightning. This proposed 
requirement would primarily focus on the recovery of the function to 
normal operation. For these systems, ``damaged'' refers to the 
inability to recover. As with the proposed standard for protection 
against catastrophic failure, the FAA would determine what constitutes 
a ``timely'' recovery of normal function based on engineering judgment 
of the specific function and its failure effects upon the design 
submitted for certification.
    An example of a function for which failure could result in or have 
a hazardous or major effect on aircraft operation is voice 
communication provided by radio. Failure of this function would 
increase the flightcrew's normal workload and affect their ability to 
maintain situational awareness, as the flightcrew would no longer be 
able to transmit or receive voice communication information with other 
pilots or air traffic control. As proposed, the applicant would be 
required to ensure the radio system is not damaged after lightning 
exposure and the voice communication function would recover in a timely 
manner. Recovery may require flightcrew interaction.

B. Applicability of the Proposed Lightning Protection Requirements

    Application of the proposed standards for aircraft electrical and 
electronic system lightning protection would be based on the aircraft's 
potential for lightning exposure and the consequences of system 
failure. The proposed requirements for parts 25 and 29 would apply to 
all aircraft certificated under part 25 and part 29. The proposed 
requirements would also apply to part 23 and part 27 aircraft approved 
for operations under instrument flight rules (IFR). In addition, the 
proposed requirements would apply to part 23 airplanes and part 27 
rotorcraft approved solely for operations under visual flight rules 
(VFR); for those electrical and electronic systems that perform 
functions for which failures would be catastrophic.
Parts 25 and 29 Aircraft
    Parts 25 and 29 transport category aircraft are now routinely 
equipped with complex electrical and electronic systems. These systems 
are highly integrated, and provide a range of flight-critical 
functions. The FAA has tentatively determined that these transport 
category aircraft should be required to provide full protection for 
those systems that perform functions for which failure could result in 
both catastrophic and hazardous or major failure effects.
Part 23 Airplanes
    Application of the proposed requirements for airplanes certificated 
to part 23 standards depends on whether the airplane is approved for 
IFR or VFR-only operations. This difference exists because, compared to 
part 23 VFR-only airplanes, part 23 IFR-approved airplanes are more 
likely equipped with complex electrical and electronic systems that 
allow them to operate into instrument meteorological conditions (IMC), 
where lightning strikes are prevalent. As a result, part 23 IFR-
approved airplanes are designed for, and expected to operate into, 
weather conditions that present greater potential for exposure to 
lightning.
    In contrast, part 23 VFR-only airplanes are prohibited by 
regulation from operating into IMC. Nevertheless, there is still some 
likelihood of the airplanes being exposed to lightning. Therefore, the 
FAA has determined that the resulting risk to part 23 VFR-only 
airplanes for which failure would be catastrophic may be sufficiently 
great to require lightning protection to prevent catastrophic failures. 
However, the FAA has tentatively determined that the resulting risk to 
part 23 VFR-only airplanes with electrical or electronic systems 
installed for which failure would be hazardous or major remains 
sufficiently low as to not require lightning protection.

[[Page 16679]]

Part 27 Rotorcraft
    Similar to the applicability of proposed changes to part 23, 
application of the proposed requirements for part 27 would depend on 
whether the rotorcraft is approved for IFR or VFR-only operations. The 
proposed lightning protection requirements would apply to IFR-approved 
rotorcraft in the same way, and for the same reasons. Likewise, part 27 
VFR-only rotorcraft would be required to protect those systems that 
perform functions where failure could have catastrophic effects. This 
requirement is intended to address the unique performance capabilities 
that make rotorcraft VFR operations vulnerable to lightning. Rotorcraft 
are inherently more maneuverable, and have more versatile landing 
capability than fixed wing aircraft. Accordingly, they are permitted to 
operate with low minimum altitude, low flight visibility, and nearer to 
clouds. Although prohibited from operating directly into IMC, part 27 
VFR-only rotorcraft are able to operate close to meteorological 
conditions that have a high potential for lightning strikes. This means 
rotorcraft certificated to part 27 standards in VFR-only operations are 
likely to encounter lightning exposure. The FAA has determined that the 
resulting risk to part 27 VFR-only rotorcraft systems for which failure 
would be catastrophic is sufficiently great to propose requiring 
lightning protection to prevent catastrophic failures. As with part 23 
VFR-only airplanes, the FAA has determined that the resulting risk to 
rotorcraft certificated to part 27 standards that operate in VFR-only 
operations with electrical or electronic systems installed for which 
failure would be hazardous or major likely remains sufficiently low as 
to not require lightning protection.

C. Specific Changes to Part 25

    The proposed changes to Sec.  25.1316 are intended to rephrase the 
existing regulation to clarify intent, to reformat it so that it is in 
keeping with the other three parts, and to delete Sec.  25.1316(c) 
which sets forth specific requirements for compliance. If adopted, the 
proposal would not change the current part 25 practices for lightning 
protection. Rather, the proposal would shift the emphasis placed on 
protecting functions of electrical and electronic systems, and focus on 
the effects that systems and equipment failure conditions have on 
aircraft safety. The most significant change would be to clearly set 
forth lightning protection performance standards for the function and 
the system, based on the failure effects of the function.
    Section 25.1316(a) currently requires those electrical and 
electronic systems that provide functions where failure would be 
catastrophic to be designed and installed so their operation and 
operational capabilities are not adversely affected when the airplane 
is exposed to lightning. Section 25.1316(b) requires that lightning 
protection for electrical and electronic systems that perform functions 
for which failure would be hazardous or major must be designed and 
installed to ensure that these functions can be timely recovered after 
exposure to lightning.
    The proposed regulation is distinguishable from existing Sec.  
25.1316 in that it places the emphasis on the function and also sets 
forth specific standards for the function and the system respectively. 
By focusing on functions performed by systems, rather than the systems 
themselves, the proposed revision would allow the applicant to choose 
appropriate system configurations and designs to comply with this 
regulation, but would also require that the applicant demonstrate that 
the proposed configuration provides effective protection.
    Finally, the proposal would remove Sec.  25.1316(c), which contains 
specific step-by-step actions required to show compliance. The ARAC 
recommended removing Sec.  25.1316(c) because this information is more 
appropriately addressed in guidance for means of compliance. Since 
Sec.  25.1316 was adopted in 1994, significant guidance has been 
developed by the FAA and lightning technical committees. Advisory 
circulars 20-136A and 20-155 provide much more comprehensive guidance 
on means of compliance with the lightning regulations. Removing Sec.  
25.1316(c) allows for the use of means of compliance that achieve the 
intent of Sec.  25.1316(a) and (b) without the prescriptive list that 
is currently in Sec.  25.1316(c). The technology for showing compliance 
with Sec.  25.1316(a) and (b) has progressed substantially since Sec.  
25.1316 was adopted in 1994, which makes the prescriptive list in Sec.  
25.1316(c) obsolete.

D. Miscellaneous Changes

    This rulemaking would remove Sec. Sec.  27.1309(d) and 29.1309(h), 
and delete ``lightning and'' from Sec. Sec.  27.610(d)(4) and 
29.610(d)(4). Section 27.1309(d) currently governs lightning protection 
for part 27 electrical and electronic systems, and requires only that 
the applicant ``consider'' the effects of lightning according to Sec.  
27.610. Section 29.1309(h) requires only that the applicant 
``consider'' the effects of lightning. Sections 27.610(d)(4) and 
29.610(d)(4) both address general design requirements for electrical 
bonding and protection against lightning and static electricity. They 
require electrical bonding against lightning to reduce to an acceptable 
level the effects of lightning on the functioning of essential 
electrical and electronic equipment. Adoption of the proposed 
Sec. Sec.  27.1316 and 29.1316 would replace these references to 
lightning with specific performance standards for lightning protection 
of parts 27 and 29 electrical and electronic systems.
    Also, we propose to add a cross reference to Sec.  27.1316 in 
Appendix B of Part 27 on electrical and electronic system lightning 
protection for rotorcraft approved for IFR operation.

Paperwork Reduction Act

    The Paperwork Reduction Act of 1995 (44 U.S.C. 3507(d)) requires 
that the FAA consider the impact of paperwork and other information 
collection burdens imposed on the public. We have determined that there 
is no new information collection requirement 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 conform to 
International Civil Aviation Organization (ICAO) Standards and 
Recommended Practices to the maximum extent practicable. The FAA has 
determined that there are no ICAO Standards and Recommended Practices 
that correspond to these proposed regulations.

Regulatory Evaluation, Regulatory Flexibility Determination, 
International Trade Impact Assessment, and Unfunded Mandates 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 (Pub. L. 96-354) requires 
agencies to analyze the economic impact of regulatory changes on small 
entities. Third, the Trade Agreements Act (Pub. L. 96-39) 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, that they be the basis of

[[Page 16680]]

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 with 
base year of 1995). This portion of the preamble summarizes the FAA's 
analysis of the economic impact of the proposed rule.
    Department of Transportation Order DOT 2100.5 prescribes policies 
and procedures for simplification, analysis, and review of regulations. 
If the expected cost impact is so minimal that a proposed or final rule 
does not warrant a full evaluation, this order permits that a statement 
to that effect and the basis for it be included in the preamble. Such a 
determination has been made for this proposed rule. The reasoning for 
this determination follows:
    In a cost survey of industry conducted by the FAA, six of the seven 
replying firms reported no incremental cost from this proposed rule. 
One firm reported ``little or no cost.'' The reason for little or no 
incremental cost is that these firms (six out of seven) reported usage 
of Advisory Circular (AC) 20-136A, ``Protection of Aircraft Electrical/
Electronic Systems Against the Indirect Effects of Lightning,'' as 
guidance for demonstrating compliance with lightning requirements. 
Consequently, these firms are already in compliance with the proposed 
rule as it represents a codification of AC 20-136A. For manufacturers 
of Part 25 airplanes, cost changes should be minimal in any case, as 
the proposed changes in the rule are clarifying only. Moreover, four of 
the seven respondents reported at least some expected benefits from the 
proposed rule (See ``Benefits'' section below). The FAA therefore has 
determined that this proposed rule would have minimal costs with 
positive net benefits and does not warrant a full regulatory 
evaluation. The FAA requests comments with supporting justification on 
the FAA determination of minimal impact. Our analysis follows below.
    The FAA has also determined that this proposed rule is not a 
``significant regulatory action'' as defined in section 3(f) of 
Executive Order 12866, and is not ``significant'' as defined in DOT's 
Regulatory Policies and Procedures.

Total Costs and Benefits of This Rulemaking

    As noted above, there are little or no expected costs for this 
proposed rule and some benefits. The benefits therefore justify the 
costs. See details in the separate costs and benefits sections below.

Who Is Potentially Affected by This Rulemaking?

    Manufacturers of Parts 23, 25, 27, and 29 aircraft and 
manufacturers of electrical and electronic systems for those aircraft.

Assumptions and Sources of Information

     We use a ten-year period of analysis, 2009-2018.
     Data on costs of compliance and benefits of this rule were 
obtained from an FAA survey of industry.
     Firms are defined as ``small'' or ``large'' using Small 
Business Administration (SBA) size standards (U.S. SBA. Table of Small 
Business Size Standards Matched to North American Industry 
Classification System Codes, July 21, 2006).

Costs of This Rulemaking

    On February 9, 2009, we sent a detailed cost survey to six 
manufacturers of Parts 23, 25, 27, and 29 aircraft and three 
manufacturers of electrical and electronic systems for those aircraft. 
In addition to several detailed cost questions, the survey also asked 
one question about potential benefits from the proposed rule. We 
received four responses to this initial survey. On March 17, 2009, we 
resurveyed the five non-respondents and received three additional 
replies, although the last response came only on August 8, 2009. The 
seven responses we received were from manufacturers ranging from a 
small aircraft manufacturer (less than 1,500 employees) to the largest 
U.S. aircraft manufacturer. As shown in the table below, the 
respondents indicated little or no cost from the proposed rule.

Summary of Cost Survey Results

--------------------------------------------------------------------------------------------------------------------------------------------------------
          Firm                    Type                  Products certified to:                         Costs                           Benefits
--------------------------------------------------------------------------------------------------------------------------------------------------------
A......................  Airplane manufacturer.  Part 23.............................  No cost.............................  ``The certification process
                                                                                                                              will be less ambiguous and
                                                                                                                              slightly streamlined by
                                                                                                                              writing some of the AC 20-
                                                                                                                              136A requirements directly
                                                                                                                              into the regulations.''
B......................  Airplane manufacturer.  Parts 23 & 25.......................  No cost.............................  ``The commonality between
                                                                                                                              parts and the ability to
                                                                                                                              use the same
                                                                                                                              substantiation across
                                                                                                                              product lines is a very
                                                                                                                              large benefit.''
C......................  Airplane manufacturer.  Parts 23 & 25.......................  No cost.............................  ``Harmonization of Part 23
                                                                                                                              and Part 25 rules will
                                                                                                                              simplify our certification
                                                                                                                              process as our internal
                                                                                                                              procedures benefit from
                                                                                                                              any similarity of the two
                                                                                                                              Parts.''
D......................  Airplane manufacturer.  Part 25.............................  Little or no cost...................  No response to benefits
                                                                                                                              question.
E......................  Electrical/electronic   Parts 23 & 25.......................  No cost.............................  ``NA.''
                          systems manufacturer.
F......................  Electrical/electronic   Parts 23, 25, 27, & 29..............  No cost.............................  ``None.''
                          systems manufacturer.
G......................  Electrical/electronic   Parts 23, 25, 27, & 29..............  No cost.............................  ``Standardization of the
                          systems manufacturer.                                                                               rule across all aircraft
                                                                                                                              types may simplify
                                                                                                                              requirements capture
                                                                                                                              resulting in some
                                                                                                                              limit[ed] non-recurring
                                                                                                                              cost reduction.''
--------------------------------------------------------------------------------------------------------------------------------------------------------

Benefits of This Rulemaking

    As supported by the responses to the benefits question, shown in 
the table, the proposed rule and the standardization of rule language 
would reduce firm costs by clarifying and simplifying the certification 
process.

Regulatory Flexibility Determination

    The Regulatory Flexibility Act of 1980 (Pub. L. 96-354) (RFA) 
establishes ``as a principle of regulatory issuance that

[[Page 16681]]

agencies shall endeavor, consistent with the objectives of the rule and 
of applicable statutes, to fit regulatory and informational 
requirements to the scale of the businesses, organizations, and 
governmental jurisdictions subject to regulation. To achieve this 
principle, agencies are required to solicit and consider flexible 
regulatory proposals and to explain the rationale for their actions to 
assure that such proposals are given serious consideration.'' The RFA 
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 rule will 
have a significant economic impact on a substantial number of small 
entities. If the agency determines that it will, the agency must 
prepare a regulatory flexibility analysis as described in the RFA. 
However, if an agency determines that a rule is not expected to have a 
significant economic impact on a substantial number of small entities, 
section 605(b) of the RFA 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.
    As noted above, in a cost survey of industry, the FAA found little 
or no expected costs from this proposed rule. The reason for this 
finding is that all but one respondent reported usage of AC 20-136A, 
``Protection of Aircraft Electrical/Electronic Systems Against the 
Indirect Effects of Lightning,'' as guidance for complying with system 
lightning requirements. Accordingly, this proposed rule represents 
current practice and imposes no more requirements than those previously 
recommended by AC 20-136A. Consequently, these firms are already in 
compliance with the proposed rule as it represents a codification of AC 
20-136A. For manufacturers of Part 25 airplanes, cost changes should, 
in any case, be minimal as the proposed changes in the rule are 
clarifying only. Therefore, the FAA certifies that this proposed rule 
would not have a significant economic impact on a substantial number of 
small entities. The FAA solicits comments regarding this determination.

International Trade Impact Assessment

    The Trade Agreements Act of 1979 (Pub. L. 96-39), as amended by the 
Uruguay Round Agreement Act (Pub. L. 103-465), prohibits Federal 
agencies from establishing any standards or engaging in related 
activities that create unnecessary obstacles to the foreign commerce of 
the United States. Pursuant to these Acts, the establishment of 
standards is not considered not considered an unnecessary obstacle to 
the foreign commerce of the United States, so long as the standard have 
a legitimate domestic objective, such as the protection of safety, and 
do not operate in a manner that excludes imports that meet this 
objective. The statute also requires consideration of international 
standards and, where appropriate, that they be the basis for U.S. 
standards. The FAA notes the purpose is to ensure the safety of the 
American public, and has assessed the effect of this proposed rule to 
ensure that it does not exclude imports that meet this objective. As a 
result, this proposed rule is not considered as creating an unnecessary 
obstacle to foreign commerce because the FAA found little or no 
expected costs from this proposed rule.

Unfunded Mandates Assessment

    Title II of the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-
4) 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 
(in 1995 dollars) 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 $136.1 million in lieu of $100 
million.
    This proposed rule does not contain such a mandate. The 
requirements of Title II do not apply.

Executive Order 13132, Federalism

    The FAA has analyzed this proposed rule under the principles and 
criteria of Executive Order 13132, Federalism. We determined that this 
action would not have a substantial direct effect 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.

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.

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, it is not a 
``significant regulatory action'' under Executive Order 12866 and DOT's 
Regulatory Policies and Procedures.

Additional Information

Comments Invited

    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. To ensure the docket does not contain 
duplicate comments, please send only one copy of written comments, or 
if you are filing comments electronically, please submit your comments 
only one time.
    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. 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 after the comment period has 
closed if it is possible to do so without incurring expense or delay. 
We may change this proposal in light of the comments we receive.

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.

[[Page 16682]]

    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 we 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 Rulemaking Documents

    You can get an electronic copy of rulemaking documents using the 
Internet by--
    1. Searching the Federal eRulemaking Portal (http://
www.regulations.gov);
    2. Visiting the FAA's Regulations and Policies Web page at http://
www.faa.gov/regulations_policies or
    3. Accessing the Government Printing Office's Web page at 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, ARM-1, 800 Independence 
Avenue, SW., Washington, DC 20591, or by calling (202) 267-9680. Make 
sure to identify the docket or notice number of this rulemaking.
    You may access all documents the FAA considered in developing this 
proposed rule, including economic analyses and technical reports, from 
the Internet through the Federal eRulemaking Portal referenced in 
paragraph (1).

List of Subjects

14 CFR Part 23

    Aircraft, Aviation safety, Signs and symbols.

14 CFR Part 25

    Aircraft, Aviation safety, Reporting and recordkeeping 
requirements.

14 CFR Part 27

    Aircraft, Aviation safety.

14 CFR Part 29

    Aircraft, Aviation 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, 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 new Sec.  23.1306 to read as follows:

Sec.  23.1306  Electrical and electronic system lightning protection.

    (a) Each electrical and electronic system that performs a function, 
for which 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 lightning; and
    (2) The system automatically recovers normal operation of that 
function in a timely manner after the airplane is exposed to lightning.
    (b) For airplanes approved for instrument flight rules operation, 
each electrical and electronic system that performs a function, for 
which 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 that--
    (1) The system is not damaged after the airplane is exposed to 
lightning; and
    (2) The function recovers normal operation in a timely manner after 
the airplane is exposed to lightning.

PART 25--AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES

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

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

    4. Revise Sec.  25.1316 to read as follows:

Sec.  25.1316  Electrical and electronic system lightning protection.

    (a) Each electrical and electronic system that performs a function, 
for which 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 lightning; and
    (2) The system automatically recovers normal operation of that 
function in a timely manner after the airplane is exposed to lightning.
    (b) Each electrical and electronic system that performs a function, 
for which 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 that--
    (1) The system is not damaged after the airplane is exposed to 
lightning; and
    (2) The function recovers normal operation in a timely manner after 
the airplane is exposed to lightning.

PART 27--AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT

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

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

    6. Amend Sec.  27.610 by revising paragraph (d)(4) to read as 
follows:

Sec.  27.610  Lightning and static electricity protection.

* * * * *
    (d) * * *
    (4) Reduce to an acceptable level the effects of static electricity 
on the functioning of essential electrical and electronic equipment.

Sec.  27.1309  [Amended]

    7. Amend Sec.  27.1309 by removing paragraph (d).
    8. Add a new Sec.  27.1316 to read as follows:

Sec.  27.1316  Electrical and electronic system lightning protection.

    (a) Each electrical and electronic system that performs a function, 
for which 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 lightning; and
    (2) The system automatically recovers normal operation of that 
function in a timely manner after the rotorcraft is exposed to 
lightning.
    (b) For rotorcraft approved for instrument flight rules operation, 
each electrical and electronic system that performs a function, for 
which 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 that--
    (1) The system is not damaged after the rotorcraft is exposed to 
lightning; and
    (2) The function recovers normal operation in a timely manner after 
the rotorcraft is exposed to lightning.
    9. Add paragraph X. to Appendix B of part 27 to read as follows:

[[Page 16683]]

Appendix B to Part 29--Airworthiness Criteria for Helicopter Instrument 
Flight

* * * * *
    X. Electrical and electronic system lightning protection. For 
regulations concerning lightning protection for electrical and 
electronic systems, see Sec.  27.1316.

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. Amend Sec.  29.610 by revising paragraph (d)(4) to read as 
follows:

Sec.  29.610  Lightning and static electricity protection.

* * * * *
    (d) * * *
    (4) Reduce to an acceptable level the effects of static electricity 
on the functioning of essential electrical and electronic equipment.

Sec.  29.1309  [Amended]

    12. Amend Sec.  29.1309 by removing paragraph (h).
    13. Add new Sec.  29.1316 to read as follows:

Sec.  29.1316  Electrical and electronic system lightning protection.

    (a) Each electrical and electronic system that performs a function, 
for which 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 lightning; and
    (2) The system automatically recovers normal operation of that 
function in a timely manner after the rotorcraft is exposed to 
lightning.
    (b) Each electrical and electronic system that performs a function, 
for which 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 that--
    (1) The system is not damaged after the rotorcraft is exposed to 
lightning; and
    (2) The function recovers normal operation in a timely manner after 
the rotorcraft is exposed to lightning.

    Issued in Washington, DC, on March 29, 2010.
Kalene C. Yanamura,
Acting Director, Aircraft Certification Service.
[FR Doc. 2010-7525 Filed 4-1-10; 8:45 am]
BILLING CODE 4910-13-P