Safety Standards for Flight Guidance Systems, 18183-18192 [06-3467]

Agencies

• Federal Aviation Administration
• DEPARTMENT OF TRANSPORTATION

[Federal Register Volume 71, Number 69 (Tuesday, April 11, 2006)]
[Rules and Regulations]
[Pages 18183-18192]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 06-3467]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No.: FAA-2004-18775; Amendment No. 25-119]
RIN 2120-AI41


Safety Standards for Flight Guidance Systems

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: This action amends the airworthiness standards for new designs 
and significant product changes for transport category airplanes 
concerning flight guidance systems. The standards address the 
performance, safety, failure protection, alerting, and basic 
annunciation of these systems. This rule is necessary to address flight 
guidance system vulnerabilities and to consolidate and standardize 
regulations for functions within those systems. In addition, this rule 
updates the current regulations regarding the latest technology and 
functionality. Adopting this rule eliminates significant regulatory 
differences between the U.S. and European airworthiness standards.

DATES: Effective Date: This amendment becomes effective May 11, 2006.

FOR FURTHER INFORMATION CONTACT: Gregg Bartley, FAA, Airplane and 
Flight Crew Interface Branch (ANM-111), Transport Airplane Directorate, 
Aircraft Certification Service, 1601 Lind Avenue SW., Renton, 
Washington 98055-4056; telephone (425) 227-2889; facsimile 425-227-
1320; e-mail gregg.bartley@faa.gov.

SUPPLEMENTARY INFORMATION:

Availability of Rulemaking Documents

    You can get an electronic copy using the Internet by:
    (1) Searching the Department of Transportation's electronic Docket 
Management System (DMS) web page (https://dms.dot.gov/search);
    (2) Visiting the FAA's Regulations and Policies Web page at https://
www.faa.gov/regulations_policies; or
    (3) Accessing the Government Printing Office's Web page at https://
www.gpoaccess.gov/fr/.
    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 amendment number or docket number of this 
rulemaking.

[[Page 18184]]

    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 (Volume 65, Number 70; Pages 19477-78) or you may visit 
https://dms.dot.gov.

Small Business Regulatory Enforcement Fairness Act

    The Small Business Regulatory Enforcement Fairness Act (SBREFA) of 
1996 requires the FAA to comply with small entity requests for 
information or advice about compliance with statutes and regulations 
within its jurisdiction. If you are a small entity and you have a 
question regarding this document, you may contact its local FAA 
official, or the person listed under FOR FURTHER INFORMATION CONTACT. 
You can find out more about SBREFA on the Internet at https://
www.faa.gov/regulations_policies/rulemaking/sbre_act/.

Authority for This Rulemaking

    The FAA's authority to issue rules regarding 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, ``General 
requirements.'' Under that section, the FAA is charged with promoting 
safe flight of civil aircraft in air commerce by prescribing minimum 
standards required in the interest of safety for the design and 
performance of aircraft; regulations and minimum standards in the 
interest of safety for inspecting, servicing, and overhauling aircraft; 
and regulations for other practices, methods, and procedures the 
Administrator finds necessary for safety in air commerce. This 
regulation is within the scope of that authority because it 
prescribes--New safety standards for the design of transport category 
airplanes, and New requirements that are necessary for safety for the 
design, production, operations, and maintenance of those airplanes, and 
for other practices, methods and procedures relating to those 
airplanes.

I. Executive Summary

    This rule revises the airworthiness standards for transport 
category airplanes to improve the performance of flight guidance 
systems in assisting the flightcrew in the basic control and guidance 
of the airplane. As discussed in more detail later, for purposes of 
this rulemaking, a ``flight guidance system'' consists of equipment 
providing autopilot, autothrust, flight director, and related 
functions. This rule adopts requirements to provide workload relief to 
the flightcrew and a means to fly an intended flight path more 
accurately. This rule responds to a series of incidents and accidents 
that have highlighted difficulties for flightcrews interacting with the 
increasing automation of flight decks.

Accident History

    The National Transportation Safety Board (NTSB) issued the 
following safety recommendations that are addressed by this rule:
     NTSB Safety Recommendation A-92-035 is a result of the 
Airbus Industries A300 accident in Nagoya, Japan, on April 26, 1994, 
where 264 people died. Contributing to that accident were conflicting 
actions taken by the flightcrew and the airplane's autopilot. The NTSB 
recommended that the FAA ``revise Advisory Circular 25.1329-1A to add 
guidance regarding autopilot failures that can result in changes in 
attitude at rates that may be imperceptible to the flightcrew and thus 
remain undetected until the airplane reaches significant attitude 
deviations.''
     NTSB Safety Recommendation A-98-098 is a result of an 
accident on November 12, 1995. A Boeing MD-80 operated by American 
Airlines descended below the minimum descent altitude, clipped some 
trees, and landed short of the runway in what was very nearly a fatal 
accident. The NTSB recommended that the FAA ``require all manufacturers 
of transport-category airplanes to incorporate logic into all new and 
existing transport-category airplanes that have autopilots installed to 
provide a cockpit aural warning to alert pilots when the airplane's 
bank and/or pitch exceeds the autopilot's maximum bank and/or pitch 
command limits.''
     NTSB Safety Recommendation A-99-043 is a result of an 
accident on July 13, 1996. A Boeing MD-11 operated by American Airlines 
experienced an in-flight upset during the descent to 24,000 feet by 
means of the autopilot. During the descent, the captain instructed the 
first officer to slow the rate of descent. Flight data recorder data 
show the airplane experienced an immediate 2.3 G pitch upset followed 
by more oscillations, resulting in four injuries. The NTSB recommended 
that the FAA ``require all new transport category airplane autopilot 
systems to be designed to prevent upsets when manual inputs to the 
flight controls are made.''
    In response to these NTSB safety recommendations and several 
incidents and accidents that highlight difficulties for flightcrews 
interacting with the increasing automation of flight decks, the FAA 
formed a Human Factors Team (HFT). The HFT issued a report on June 18, 
1996, titled ``The Interfaces Between Flightcrews and Modern Flight 
Deck Systems.''

Past Regulatory Approach

    Currently, Sec.  25.1329, ``Automatic pilot system'' addresses only 
the autopilot system, and Sec.  25.1335, ``Flight director systems'' 
addresses the flight director switch position. Not addressed is the 
autothrust system and how it relates to flight guidance. The existing 
regulations need to be updated to match technology advances. Current 
regulations do not fully address the latest technology or newly 
available functionality. In addition, proposed and recent rulemaking 
activity regarding the interaction of systems and structure, flight 
test, and human factors will make certain aspects of the existing 
flight guidance systems regulations redundant, in conflict with other 
regulations, or confusing and difficult to understand.

Summary of the Rule

    This rule adopts new airworthiness standards specifically to 
address potential pilot confusion about various aspects of the 
operation of flight guidance systems (FGS), including automatic mode 
reversions, hazardous disengagement transients, speed protection, and 
potential hazards during an autopilot override. These new standards 
will apply to new designs and some design changes (as required under 14 
CFR 21.101) for transport category airplanes.
    This rule revises, reorganizes, and adds additional material to 
address the performance, safety, failure protection, alerting, and 
basic annunciation of these systems. This rule addresses the autopilot, 
autothrust, and flight director in a single section. This rule covers 
the portion of the head up display (HUD) that contains flight-guidance 
information displayed to the pilot while manually flying the airplane.
    Finally, this rule harmonizes the regulations for FGS between the 
FAA

[[Page 18185]]

and the European Airworthiness Authorities. This harmonization will not 
only benefit the aviation industry economically, but also maintain the 
necessary high level of aviation safety.

Summary of the Regulatory Evaluation

    The FAA's analysis of the economic impacts of this final rule is 
consistent with various Federal directives and orders. The FAA 
determined that this rule:
     Has benefits that justify its costs;
     Is not a significant regulatory action;
     Will not have a significant impact on a substantial number 
of small entities;
     Is in compliance with the Trade Agreements Act; and
     Will not impose an unfunded mandate of $100 million or 
more, in any one year, on state, local, or tribal governments, or on 
the private sector.
    This rule affects manufacturers of small part 25 airplanes and the 
occupants of these airplanes. The manufacturers may incur costs; 
however, the occupants in the affected airplanes will receive safety 
benefits.
    This rule incorporates the FAA and European Aviation Safety 
Agency's (EASA) harmonized standards that result in the assessed 
improvements in the operation of autopilot systems and has potential 
cost savings.
    The FAA has determined that this rule will be cost-beneficial if 
seven accidents are averted over a 34-year benefits period.\1\ Although 
it is not certain that earlier events could have been prevented by 
these autopilot changes (or, how many of any potential future accidents 
would be catastrophic), the expected prevalence of more sophisticated 
autopilot systems in business jets, combined with the occurrence of 
serious accidents involving large transport category airplanes, 
mandates regulatory action. For these reasons, the FAA finds this rule 
to be cost-beneficial.
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    \1\ A copy of the full regulatory evaluation is available in the 
Docket.
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II. Background

A. General Discussion of the Rule

    This amendment is based on notice of proposed rulemaking (NPRM), 
Notice No. 04-11, which was published in the Federal Register on August 
13, 2004 (69 FR 50240). In the Notice, you will find the background 
material and a discussion of the safety considerations supporting our 
course of action. You also will find a discussion of the current 
requirements and why they do not adequately address the problem. We 
refer to the recommendations of the Aviation Rulemaking Advisory 
Committee (ARAC) and the NTSB that we relied on in developing the final 
rule. The ARAC report is available at the following Web address: http:/
/dms.dot.gov. The NTSB recommendations No. A-98-098 and A-99-043 are 
available at the following Web address: https://www.ntsb.gov/Recs/
letters/letters.htm. The FAA Human Factors Report and NTSB 
recommendation No. A-92-035 are available in the public docket for this 
rulemaking. The NPRM also discusses each alternative that we considered 
and the reasons for rejecting the ones we did not propose.
    The background material in the NPRM contains the basis and 
rationale for this rule and, except where we have specifically expanded 
on the background elsewhere in this preamble, supports this final rule 
as if it were contained here. The table in the NPRM describing non-
normal conditions has been updated. Refer to the table in Advisory 
Circular (AC) 25.1329-1B, ``Approval of Flight Guidance Systems'' for 
the newest language. We refer inquiries regarding the intent of the 
requirements to the background in the NPRM as though it was in the 
final rule itself. It is therefore not necessary to repeat the 
background in this document.

B. Overview of the Flight Guidance System

    The FGS is intended to assist the flightcrew in the basic control 
and guidance of the airplane. The FGS provides workload relief to the 
flightcrew and a means to fly an intended flight path more accurately. 
The following functions make up the flight guidance system:
    1. Autopilot--automated airplane maneuvering and handling 
capabilities.
    2. Autothrust--automated propulsion control.
    3. Flight Director--the display of steering commands that provide 
vertical and horizontal path guidance, whether displayed ``head down'' 
or ``head up.'' A head up display is a flight instrumentation that 
allows the pilot of an airplane to watch the instruments while looking 
ahead of the airplane for the approach lights or the runway.
    Flight guidance system's functions also include flight deck 
alerting, status, mode annunciations (instrument displays), and any 
situational information required by those functions displayed to the 
flightcrew. Also included are those functions necessary to provide 
guidance and control with an approach and landing system, such as:
     Instrument landing system (ILS).
     Microwave landing system (MLS) (an instrument landing 
system operating in the microwave spectrum that provides lateral and 
vertical guidance to airplanes having compatible avionics equipment).
     Global navigation satellite system landing system (GLS).
    The FGS definition does not include flight planning, flight path 
construction, or any other function normally associated with a flight 
management system (FMS).

C. Authorities

    In addition to the FAA and JAA, a new aviation regulatory body, the 
EASA, was established recently by the European community to develop 
standards to ensure the highest level of safety and environmental 
protection, oversee their uniform application across Europe, and 
promote them internationally. The EASA formally became operational for 
certification of aircraft, engines, parts, and appliances on September 
28, 2003. The EASA will eventually absorb all of the functions and 
activities of the JAA, including its efforts to harmonize the European 
airworthiness certification regulations with those of the U.S.
    The Joint Aviation Regulation (JAR)-25 standards have been 
incorporated into the EASA's ``Certification Specifications for Large 
Aeroplanes,'' (CS)-25, in similar if not identical language. The EASA's 
CS-25 became effective October 17, 2003.
    The standards in this amendment were developed before the EASA 
began operations. They were developed in coordination with the JAA and 
JAR-25. However, since the JAA's JAR-25 and the EASA's CS-25 are 
essentially the same, all of the discussions relative to JAR-25 also 
apply to CS-25.

D. Harmonization of U.S. and European Regulatory Standards

    When airplanes are type certificated to both sets of standards, the 
differences between part 25 and JAR-25 can result in substantial added 
costs to manufacturers and operators. These added costs, however, 
frequently do not bring about an increase in safety.
    Representatives of the FAA and JAA, proposed an accelerated process 
to reach harmonization, the ``Fast Track Harmonization Program.'' The 
FAA initiated the Fast Track Harmonization Program on November 26, 
1999.
    For ``fast track harmonization'' projects, the FAA and the JAA 
agreed that, ``During the development of the NPRM, the rulemaking team 
should coordinate closely with the JAA HWG [Harmonization Working 
Group]

[[Page 18186]]

representative to ensure continued harmonization of approaches between 
the NPRM and JAA NPA [Notice of Proposed Amendment]. During these 
discussions, it should be emphasized that harmonization means that the 
regulations would have the same effect, thereby allowing single 
certification/validation, rather than be worded identically. To the 
extent necessary, the rulemaking team will have cooperation from other 
HWG members to ensure a full understanding of the issues.'' \2\ This 
rulemaking has been identified as a ``fast track'' project.
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    \2\ See Fast Track Harmonization Program (ANM-99-356-A) referred 
to in FAA Order 1100.160, and the NPRM mentioned above.
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    Further details on ARAC, and its role in harmonization rulemaking 
activity, and the Fast Track Harmonization Program can be found in the 
tasking statement (64 FR 66522, November 26, 1999) and the first NPRM 
published under this program, ``Fire Protection Requirements for 
Powerplant Installations on Transport Category Airplanes'' (65 FR 
36978, June 12, 2000).

III. Disposition of Comments

Safety Standards for Flight Guidance Systems

    In response to the NPRM request for comments, ten commenters 
responded (with one commenter sending a duplicate). The commenters 
include one foreign regulatory authority, foreign and domestic airplane 
operators and manufacturers and the aviation organizations representing 
them, and individuals. One supportive comment finds the level of safety 
significantly improved. A number of comments, while generally 
supporting the proposal, suggest changes. Two comments ask for 
clarification of a term or definition. A few comments suggest 
rulemaking actions not addressed by the proposal, and several comments 
concern changes to the proposed AC. No substantive changes were made to 
the proposed rule; however, we revised the rule text in paragraph (h) 
to clarify our intent. The comments and our responses are below.\3\
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    \3\ The full text of each commenter's submission is available in 
the Docket.
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1. Significant Transient, Paragraph (e)
    Transport Canada, Canada's airworthiness authority, stated that the 
proposed rule's definition of a ``significant transient'' is 
inappropriate, as it includes criteria containing an injury level 
(i.e., ``non-fatal injuries'') to crew and passengers. Transport Canada 
believes that the term could be open to considerable individual 
interpretation, and needlessly complicates the issue. In addition, this 
commenter argued that both the rule and the guidance material allow for 
a significant transient following autopilot disengagement during non-
normal and rare-normal events. The more logical approach would be to 
delete any reference to injury level, and allow for the discretion of 
the certification specialist to determine whether any transients, be 
they minor or significant, are acceptable.
    As discussed in the NPRM, the reference to ``non-fatal injuries'' 
was made for several reasons. The terms ``significant transient'' and 
``minor transient'' are used in Sec.  25.1329(c), (d), and (e). These 
terms are defined using AC 25.1309-1A language for ``major failure 
condition'' and ``minor failure condition,'' respectively. The FAA 
intends a strong correlation between the terms used in these rule 
paragraphs regarding allowable transient conditions and the hazard 
classifications of failures of AC 25.1309-1A. Therefore, identical 
language is used so there would be no confusion about the hazard 
classification of the different transient levels defined in Sec.  
25.1329. This is consistent with the ARAC recommendation regarding the 
meaning of these terms and their relationship to acceptable means of 
compliance with Sec.  25.1309. One reason for establishing this close 
relationship is to enhance standardization in the application of these 
terms and to make this application less dependent on the judgment of 
individual certification specialists. No changes were made to the rule 
due to this comment.
2. Changed Product Rule (CPR), Sec.  21.101
    The NPRM addressed the applicability of this rule given the intent 
behind the CPR, in depth, under the section entitled ``Discussion of 
Proposal.'' In its comment, Boeing neither raised any questions 
regarding this explanation, nor identified issues for which this 
explanation was inadequate, although it did request further 
clarification of the inter-relationship between the two rules 
generally. To summarize the NPRM discussion, the CPR must be considered 
when updating or adding a flight guidance system. If a proposed change 
to a FGS is part of a ``significant'' product change, then Sec.  
21.101(a) is applicable unless one of the other exceptions of Sec.  
21.101(b) applies. For changes that are limited to the FGS itself, the 
only time a change may be considered a ``significant change'' is when a 
substantially new function is included in an already certified product. 
Advisory Circular 21.101-1, Change 1, further discusses how to evaluate 
whether a change made to a previously certified product is significant 
or not significant.
    In accordance with Sec.  21.101(b)(3), an applicant proposing a 
significant change would not be required to comply with this amendment 
if compliance were determined to be impractical. So, applicants for 
design changes, even if they are significant, will not be required to 
comply with this amendment if they show that it is impractical to 
comply. The determination of whether compliance is impractical is made 
for each amendment on a requirement-by-requirement basis. For example, 
in this rule it may be determined that it is impractical to comply with 
certain paragraphs of Sec.  25.1329, but practical to comply with 
others. The applicant and the FAA may consider the question of whether 
or not complying with the latest amendment of the rule is impractical 
during the certification of a changed product. No change was made due 
to this comment.
3. Pilot Override, Paragraph (d), and Preamble Changes
    Dassault Aviation disagreed with the statement made in the NPRM 
that an autopilot override and subsequent disengagement is considered 
to be a normal event. This topic is discussed in the NPRM under the 
heading, ``What Are The Specific Proposed Changes?'' for proposed Sec.  
25.1329(c), (d), and (e).
    Dassault believes that part 25 aircraft certified to the current 
standards have an excellent safety record. However, it recognized that 
part 25 aircraft are becoming increasingly automated. The commenter 
further recognized that recent technological improvements make it 
feasible to include a level of protection against override events, thus 
making future part 25 aircraft and their flight guidance systems even 
safer.
    Consequently, the commenter supports reasonable and feasible steps 
to provide additional protection against a manual override of an 
engaged autopilot. Nevertheless, Dassault emphasized that the primary 
responsibility for proper operation of the FGS (or any other system) 
rests with the pilot in command and the only way for the pilot to 
fulfill that responsibility is to possess adequate knowledge of 
aircraft systems and to use proper operational procedures, especially 
those that pertain to the FGS.
    The FAA included the explanation regarding a pilot override as a 
normal event in the NPRM due to a comment received during discussions 
among the

[[Page 18187]]

FGS working group. The comment, that a pilot override of an engaged FGS 
should be a ``non-normal condition,'' was made because the commenter 
believed that, since an override is not the primary means to disengage 
an engaged FGS, it must, therefore, be a non-normal condition.
    As discussed in the NPRM, the FAA disagrees with that assessment.
    The current generation of FGS has flown for millions of flight 
hours and is safe. However, there have been several accidents and 
incidents in the past 15 years whose initiating event was a pilot 
override of an engaged FGS. This specific scenario, a pilot override of 
an engaged FGS, is one of the known ``vulnerabilities'' of current FGS 
systems, and one that was addressed by ARAC's proposed rule language 
and accompanying AC.
    We disagree with the commenter's implication that the pilot will 
always disconnect the FGS before making a manual input to the flight 
controls. History has shown that the pilots may not always follow this 
training, sometimes resulting in the accidents and incidents discussed 
in the NPRM. Whether a pilot chooses to override an engaged FGS because 
of an immediate need to maneuver the airplane, such as a need to avoid 
oncoming traffic, or a desire to ``assist'' the FGS because the pilot 
does not believe the FGS is performing as desired, the results of this 
pilot action must be safe and must not put the crew or passengers in 
jeopardy. This is the effect of treating pilot override of the FGS as a 
``normal'' event under this rule. No change was made due to this 
comment.
4. Minor Transient Used in the Icing Table and in the Definition of 
Icing Conditions in Paragraph (c)
    An individual commented on the preamble explanatory material of 
proposed Sec.  25.1329(c), (d), and (e); the discussion of transients 
and their definition; and the explanatory text in proposed paragraph 
(c) that reads: ``For purposes of this section, a minor transient is an 
abrupt change in the flight path of the airplane that would not 
significantly reduce airplane safety, and which involves flightcrew 
actions that are well within their capabilities involving a slight 
increase in flightcrew workload or some physical discomfort to 
passengers or cabin crew.''
    This commenter disagreed with the definition in paragraph (c) of 
``minor transient,'' stating that the definition conveys that it is 
necessarily abrupt, that it does involve an increase in crew workload, 
and that it does involve physical discomfort. Even though paragraphs 
(c) and (d) do state ``* * * may not cause * * * any greater than a 
minor transient,'' the commenter thinks it would be helpful if the 
ensuing definition incorporated the same concept. This commenter 
recommended changing paragraph (c) to read ``For the purposes of this 
section, a minor transient is a response that produces no greater than 
an abrupt change * * * ''
    The FAA does not agree with the suggested revision and has made no 
rule language change due to this comment. The rule defines the minimum 
performance safety requirements for an FGS. The FAA agrees that any 
transient, regardless of the duration or abruptness, is not desirable 
in a modern FGS. However, the purpose of the rule is not to address 
nuisance performance issues that are not safety critical.
    Rule paragraphs (c) and (d) state that, for the conditions 
described in each paragraph, the resultant response may not be any 
greater than a minor transient. This addresses the commenter's concern 
that is reflected in the suggested revision. The definition of a 
``minor transient'' does not need to reflect the possible range of 
response from ``no response at all'' to the maximum allowable transient 
that can be categorized as a minor transient.
5. Icing Definitions Listed in the Table
    The same individual also stated that the definitions for icing 
conditions given under the description of ``normal conditions'' in the 
NPRM preamble should include ``icing, (trace, light and moderate).'' 
The commenter suggested that the current text may ``possibly constitute 
a significant regulatory difference (SRD) between Sec.  25.1329 and the 
corresponding JAR regulations, without referring to the AC or ACJ, 
which is only one means of compliance.'' Additionally, the commenter 
suggested that the wording in the proposed rule text and NPRM preamble 
is not as stringent as the ARAC working group recommendation.
    The commenter suggested adding another sentence in the table for 
``normal conditions `` icing'' that conveys the concept that 
``Operationally, normal icing conditions include trace, light, and 
moderate icing levels.''
    The FAA disagrees with the statement that the proposal would create 
an SRD, and made no change. As recommended by ARAC, the proposed rule 
text uses the terms ``normal conditions,'' ``rare normal conditions,'' 
and ``non-normal conditions'' to distinguish the types of conditions 
under which the FGS must be evaluated. As explained in the 
``Discussion'' section of the NPRM, these terms are not subject to 
precise definition. However, the Discussion section includes a table 
providing extensive examples of each category of conditions. In 
particular, the table states that ``normal conditions'' include ``All 
icing conditions covered by 14 CFR part 25, appendix C, with the 
exception of ``asymmetric icing'' discussed under ``Rare Normal 
Conditions'' below.'' While appendix C does not use the terms trace, 
light, and moderate icing levels, appendix C clearly encompasses those 
terms. Therefore, we have retained the intent of the ARAC 
recommendations, and the rule is no less stringent.
6. Icing and Autopilot
    One individual stated that, although the NRPM and AC contain 
significant discussions of the effects of icing upon FGS operations, 
there is not enough discussion to conclude that ``icing can mask or 
impair the handling qualities of an autopilot.''
    The FAA believes that this issue has been covered adequately. The 
NPRM proposed requirements regarding the allowable transients during a 
disengagement of the FGS system in normal conditions and rare normal 
conditions, both of which contain icing conditions. An FGS would have 
to meet these requirements despite any ``masking'' effect or impairment 
of handling qualities of the autopilot. Likewise, the proposed AC 
25.1329-1X, that accompanied the proposed rule contains discussions of 
many different aspects of this issue, such as the functions of a new 
flight deck alert and how the effects of icing upon autopilot 
performance should be evaluated.
7. Autopilot Disengagement Clarification in Paragraph (b)
    The same individual also expressed concern that the rule language 
does not adequately address the need for a positive FGS disengagement 
(autopilot or autothrottle). The commenter stated that most current 
mechanically controlled systems uncouple from the system they are 
controlling, and will leave some mechanical connections attached to the 
system. These components increase the probability for control jams, as 
they can never be removed from the system.
    Based on ARAC's recommendation, the FGS, as the term is used in 
this rule, does not include the mechanical connections. The 
accompanying AC to this rule states, in the ``Overview of FGS'' 
section, that anything that remains attached to the primary flight 
controls or propulsion controls when the FGS is not in use is regarded 
as part

[[Page 18188]]

of the primary flight controls and propulsion system, and the 
airworthiness standards for those systems are applicable. This means 
that the concerns stated by the commenter fall under the requirements 
that govern those systems, such as Sec. Sec.  25.571, 25.671, 25.689, 
25.901, and 25.1309. Specifically, Sec. Sec.  25.671(c), 25.901(c), and 
25.1309(b) cover the possibility of mechanical jams of the flight 
controls and propulsion systems. The FAA's position is that these 
regulations adequately cover the concerns described by the commenter.
    This rulemaking action does not propose any changes to the 
regulations governing those systems. Therefore, no change to was made.
8. New Functions and Control Directions, Paragraph (f)
    Dassault Aviation stated that Sec.  25.1329(f) and Sec.  25.1329(i) 
are redundant, and that paragraph (i) is worded more in terms of design 
than regulation. Section 25.1329(f) has to do specifically with the 
marking and labeling of the FGS controls, while Sec.  25.1329(i) deals 
generally with the controls being designed to minimize confusion 
regarding FGS operations. While related, these two paragraphs deal with 
different aspects of the flightcrew interface with the FGS. The FAA 
disagrees with the commenter's assertion that the two paragraphs are 
redundant, and has made no change to the proposed rule text due to this 
comment. Rule paragraph (f) is the FGS specific regulation analogous to 
Sec.  25.1555(a), ``Control Markings.'' Rule paragraph (i) is the FGS 
specific regulation analogous to Sec.  25.777, ``Cockpit Controls,'' 
which addresses a broad range of human factors design issues. Both of 
these paragraphs are necessary to achieve this rule's safety 
objectives, and were recommended by ARAC.
9. Speed Protection Domain, new Paragraph (h)
    Dassault Aviation stated that the rule text of Sec.  25.1329(h) is 
more restrictive than the NPRM preamble discussion. The draft rule text 
states: ``* * * the flight guidance system must not provide guidance or 
control to an unsafe speed.'' The NPRM discussion stated, ``[H]owever, 
an implementation providing increased awareness of airspeed and/or 
alerts for immediate crew recognition and intervention of a potential 
airspeed excursion may also be an acceptable means of complying with 
this regulation.'' The commenter stated that FGS designs that would 
comply with the option discussed in the NPRM preamble would not be 
compliant with the formal regulation. The commenter then suggested the 
following revision to Sec.  25.1329(h): ``* * *the flight guidance 
system must not provide guidance or control to an unsafe speed unless 
an implementation providing increased awareness of airspeed and/or 
alerts for immediate crew recognition is provided.''
    The FAA partially concurs with Dassault's comment. While it was not 
our intent, we recognize that the proposed rule language could be 
interpreted as requiring the FGS itself to prevent operation at an 
unsafe speed, without pilot intervention. To clarify that such 
intervention is an acceptable means of compliance with this standard, 
we have revised the paragraph to state, ``a means must be provided to 
prevent the flight guidance system from providing guidance or control 
to an unsafe speed.'' This means may consist of either an automated 
means of preventing such guidance or pilot intervention. This 
philosophy was used elsewhere in this proposed rule and accompanying 
proposed AC. The NPRM discusses the use of another flight deck alert 
(sometimes referred to as ``Bark Before Bite'') to mitigate transients 
in the flight path of the airplane that occur immediately after the 
disengagement of the autopilot system. This alert to ensure awareness 
of the pilot to the speed of the airplane is similar to this example. 
The proposed rule, accompanying preamble material, and proposed AC are 
consistent in that the use of a flight deck alert to ensure pilot 
action is considered to be an acceptable means of compliance to the 
rule. This approach is also fully harmonized with that of JAA/EASA.
10. General Comments
    The General Aviation Manufacturers Association (GAMA) supports the 
FAA's and ARAC's effort in generating this proposed rule. The GAMA 
noted several specific NPRM preamble paragraphs that explain the intent 
and interpretation of the several proposed rule paragraphs that its 
organization supports.
    Boeing, while making a comment on the proposed AC accompanying this 
proposed rule, included the following statement concerning the NPRM, 
``The NPRM has been changed from the JAA [Joint Aviation Authority] NPA 
product * * *'' Boeing noted all instances of differences between the 
rule language contained in the NPRM and NPA.
    The NPRM, in the section entitled ``Discussion of the Proposal,'' 
explained editorial instances where the FAA proposed rule language was 
different than the JAA NPA rule language. For further information on 
harmonization, refer to section II, paragraph D, Harmonization of U.S. 
and European Regulatory Standards, of this final rule.
    Because of the differences in the rulemaking processes and 
requirements of the two Agencies, it is common that slight differences 
exist between their harmonized regulations. The FAA believes the rule 
text is harmonized between the FAA and JAA/EASA even though some terms 
used are different. Since the FAA and JAA/EASA versions of the final 
rule are harmonized--meaning the effect of both rules is identical--no 
changes were made due to these comments.
11. Comments and Suggestions for Rulemaking Actions Not Addressed by 
This NPRM
    The FAA received several comments on subject areas that are not 
addressed in the proposed rule, and therefore, no comments were 
requested on these subjects. These comments are discussed below.

Adding Flight Testing Criteria

    One commenter suggested that flight testing criteria be included in 
the rule if an FGS is to be certified based on its similarity to a 
previously approved design. The FAA disagrees with this approach. The 
commenter's suggestion is more appropriate for an AC in that it would 
define one (but not the only) method to show compliance to the 
regulations. However, in this case, the FAA disagrees with making this 
change to the accompanying AC. The AC represents the most detailed 
approach of demonstrating compliance. To use similarity as a method of 
compliance, the applicant would need to propose this method, instead of 
the method in the AC, to the FAA aircraft certification office (ACO) in 
charge of that project. The FAA believes that it would be extremely 
problematic, due to the numerous possibilities of systems, aircraft, 
and aerodynamic differences between a system to be certified and a 
previously certified system, to try to define a prescriptive method 
that would be acceptable. This evaluation is best left to the ACO 
engineer evaluating the project.

Current Systems or Component Items

    Another comment by the same individual made several observations 
regarding ``known frailties of current systems or components as they 
are implemented.'' The examples given concerned mechanical flight 
controls issues, such as control surface servo actuators, rudder boost 
pumps, and

[[Page 18189]]

worn and out of tolerance flow control valves.
    Under the definition of an FGS given in the NPRM, these items are 
not considered to be part of the FGS. They are part of the primary 
flight control system of the airplane. Therefore, no changes were made 
due to this comment. Additionally, the commenter made no specific 
recommendations to address the concerns. The FAA considers that Sec.  
25.1309 adequately covers the concerns listed.

Autopilot and Flight Standards Issue, Sec.  121.579

    One commenter reminded the FAA that the FGSHWG report recommended 
updating Sec.  121.579, ``Minimum Altitudes for Use of Autopilot.'' The 
proposed AC 25.1329-1X included an updated method for calculating the 
autopilot Minimum Use Height (MUH). The method contained in the 
proposed AC was harmonized with the JAA/EASA method. The working group 
recommended that the part 121 rule be revised so there would be no 
confusion about making the MUH calculation or placing the correct 
method in the Airplane Flight Manual (AFM).
    While we acknowledged the ARAC recommendation, we did not propose 
to revise Sec.  121.579 as part of this rulemaking, and we have not 
provided the public an opportunity to comment on the proposal. No 
changes were made due to this comment. We may consider this 
recommendation in future rulemaking.

Helicopter Autopilot, Part 27 and 29

    Rowan Companies, Inc., as the parent company of Era Aviation, Inc., 
provided detailed input on helicopter autopilot design and specific 
suggestions to include these considerations. This commenter suggested 
that the Sec.  25.1329 rulemaking and advisory material be expanded to 
include helicopters. Several specific suggestions were made to address 
what the commenter regarded as deficiencies in current rotorcraft 
regulations.
    The activity to revise part 25 material is, by its nature, 
applicable to transport category airplanes only. Part 27 of 14 CFR 
covers normal category rotorcraft, and part 29 covers transport 
category rotorcraft. Revisions to the regulations contained in parts 27 
and 29 are not covered in the proposed rulemaking for the FGS on 
transport category airplanes. However, these comments may be considered 
in future rulemaking applicable to rotorcraft.

IV. Editorial Change

    For clarification only, we have moved the definitions of ``minor 
transient'' and ``significant transient'' from paragraphs (c) and (e), 
respectively, to a new paragraph (n).

V. Rulemaking Analyses and Notices

Paperwork Reduction Act

    The Paperwork Reduction Act of 1995 (44 U.S.C. 3507(d)) requires 
that the FAA to consider the impact of paperwork and other information 
collection burdens imposed on the public. We have determined that there 
are no new information collection requirements associated with this 
final 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 has 
determined that there are no ICAO Standards and Recommended Practices 
that correspond to these regulations.

Executive Order 13132, Federalism

    The FAA analyzed this 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.

Summaries of the Regulatory Evaluation, Regulatory Flexibility 
Determination, Trade Impact Assessment, and Unfunded Mandates 
Assessment

Executive Order 12866 and DOT Regulatory Policies and Procedures

    This portion of the preamble summarizes the FAA's analysis of the 
economic impacts of this final rule. We suggest readers seeking greater 
detail read the full regulatory evaluation, a copy of which has been 
placed in the docket for this rulemaking.
    Changes to Federal regulations must undergo several economic 
analyses. First, Executive Order 12866 directs that each Federal agency 
propose or adopt a regulation only upon a 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 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, use them as 
the basis of U.S. standards. Fourth, the Unfunded Mandates Reform Act 
of 1995 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 private sector, of $100 
million or more annually (adjusted for inflation).
    In conducting these analyses, FAA has determined this rule: (1) Has 
benefits that justify its costs; (2) 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; (3) will not have a significant economic impact on a 
substantial number of small entities; (4) will reduce barriers to 
international trade; and (5) will not impose an unfunded mandate on 
state, local, or tribal governments, or on the private sector.
Total Costs and Benefits of This Rulemaking
    This rulemaking affects manufacturers of small part 25 airplanes 
that incur costs and occupants in affected airplanes that receive 
safety benefits.
Assumptions and Standard Values
     Discount rates: Base case 7%; sensitivity case 3%.
     Period of analysis: Overall, 2006-2041. Costs, 2006-2016 
(consist of design, testing, and production costs). Benefits, 2008-2041 
(based on 25-year operating lives of newly-certificated aircraft, all 
of which will be produced between 2007-2016).
     Value of statistical fatality avoided: $3 million.
Basis of Costs
    As noted in the regulatory evaluation, the revised requirements 
will affect part 25 smaller transport airplanes (turboprops and 
regional jets) and business jets; part 25 larger commercial airplanes 
either already meet the new requirements or will have only minor costs 
in complying. Since part 25 turboprops and regional jets are not 
currently manufactured in the United States, the final rule will 
directly affect only U.S.-manufactured business jets.

[[Page 18190]]

    The relevant changes and associated incremental costs are as 
follows:
    1. Autopilot Override--Nonrecurring costs (design, development, and 
testing) related to installation of a force sensor (new force 
transducer) on control column totals $200,000 for a new type 
certificate. Recurring costs (per unit) for a new force transducer 
equal $12,000.
    2. Speed Protection--Nonrecurring costs total $210,000; recurring 
costs (per unit) equal $40,000 (this amount may include new or modified 
components such as sensors).
    3. Pilot Awareness/Flight Deck Annunciation--Nonrecurring costs 
total $120,000; recurring costs per unit are minimal (essentially no 
new costs).
    Non-recurring and recurring costs total $116,520,000, or 
$76,592,390, and $96,553,992 in present values at 7% and 3% discount 
rates, respectively.
Basis of Benefits
    Since current type certificates for part 25 larger commercial 
airplanes already voluntarily meet the key provisions of the rule, 
future averted accidents (benefits) attributable to the rule must be 
limited to part 25 business jets.
    Although there were no directly-aligned accidents involving 
autopilots in part 25 business jets in a recent 20-year period, there 
were four incidents that involved autopilot disconnect and/or improper 
pilot procedures; the FAA expects this rule to prevent such events. 
Autopilot disruptions are serious occurrences, and it is reasonable to 
postulate that such incidents could just as easily have been accidents. 
Furthermore, given that part 25 business jets increasingly incorporate 
more sophisticated autopilot systems, the risk of future accidents 
intensifies. As previously noted, difficulties for flightcrews 
interacting with the increasing automation of flight decks in part 25 
larger commercial airplanes prompted this rulemaking. (There were at 
least two accidents and several serious incidents involving large 
commercial airplanes).
    Accordingly, the FAA has estimated the minimum levels of averted 
losses, in terms of avoided fatalities and airplane damage (each 
accident is valued at $40 million) that will be necessary to offset the 
estimated compliance costs.
    Applying the base case 7% interest rate, the FAA has determined 
that approximately seven catastrophic accidents are necessary in the 
34-year benefits period to make the rule cost-beneficial (note that 
four events in the 20-year period examined mathematically equates to 
seven events in the future 34-year benefits period in this analysis). 
Alternatively, using a 3% interest rate as a sensitivity case, only 
four accidents are necessary to make the rule cost-beneficial.
    Based on the history of accidents and incidents in large commercial 
airplanes, and the occurrence of incidents concomitant with the 
increasing complexity of flight guidance systems in large business 
jets, the FAA finds this rule to be cost-beneficial. A summary of costs 
and benefits is shown below.
Base Case--Use of 7% Discount Rate
     Estimated present value costs (11-year analysis period)--
part 25 certificated smaller airplanes (large business jets): $76.592 
million.
     Estimated present value benefits (34-year period)--part 25 
certificated smaller airplanes (large business jets): As discussed 
above, with seven potential averted accidents, the present value of 
benefits is equivalent to present value costs of $76.592 million, and 
the rule is cost-beneficial.
Sensitivity Case--Use of 3% Discount Rate
     Estimated present value costs (11-year period)--part 25 
certificated smaller airplanes (large business jets): $96.554 million.
     Estimated present value benefits (34-year period)--part 25 
certificated smaller airplanes (large business jets): As discussed 
above, with four potential averted accidents, the present value of 
benefits is equivalent to present value costs of $96.554 million, and 
the rule is 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 proposed or 
final rule will have a significant economic impact on a substantial 
number of small entities. If the determination is 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.
    This rule will affect manufacturers of part 25 airplanes produced 
under future new type-certificates. For manufacturers, a small entity 
is one with 1,500 or fewer employees. None of the part 25 manufacturers 
has 1,500 or fewer employees; consequently, none is considered a small 
entity.
    Based on the above, I certify that this rule will not have a 
significant economic impact on a substantial number of small entities.

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, they be the basis for U.S. standards. 
In accordance with the above statute, the FAA has assessed the 
potential effect of this rule for part 25 airplanes. This rulemaking is 
consistent with the Trade Agreements Act since it eliminates 
significant regulatory differences between the U.S. and European 
airworthiness 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 final rule does not contain such a mandate. The requirements 
of Title II of the Act, therefore, do not apply.

[[Page 18191]]

Regulations Affecting Intrastate Aviation in Alaska

    Section 1205 of the FAA Reauthorization Act of 1996 (110 Stat. 
3213) requires the Administrator, when modifying regulations in a 
manner affecting intrastate aviation in Alaska, to consider the extent 
to which Alaska is not served by transportation modes other than 
aviation, and to establish appropriate regulatory distinctions. In the 
NPRM, we requested comments on whether the proposed rule should apply 
differently to intrastate operations in Alaska. We did not receive any 
comments, and we have determined, based on the administrative record of 
this rulemaking, that there is no need to make any regulatory 
distinctions applicable to intrastate aviation in Alaska.

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 rulemaking action qualifies for the categorical 
exclusion identified in paragraph 312f and involves no extraordinary 
circumstances.

Regulations That Significantly Affect Energy Supply, Distribution, or 
Use

    The FAA has analyzed this final rule 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 in 14 CFR Part 25

    Aircraft, Aviation safety, Reporting and record keeping 
requirements, Safety, Transportation.

The Amendment

0
In consideration of the foregoing, the Federal Aviation Administration 
amends Part 25 of Chapter 1 of Title 14, Code of Federal Regulations, 
as follows:

PART 25--AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES

0
1. The authority citation for part 25 continues to read as follows:

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


0
2. Revise Sec.  25.1329 to read as follows:


Sec.  25.1329  Flight guidance system

    (a) Quick disengagement controls for the autopilot and autothrust 
functions must be provided for each pilot. The autopilot quick 
disengagement controls must be located on both control wheels (or 
equivalent). The autothrust quick disengagement controls must be 
located on the thrust control levers. Quick disengagement controls must 
be readily accessible to each pilot while operating the control wheel 
(or equivalent) and thrust control levers.
    (b) The effects of a failure of the system to disengage the 
autopilot or autothrust functions when manually commanded by the pilot 
must be assessed in accordance with the requirements of Sec.  25.1309.
    (c) Engagement or switching of the flight guidance system, a mode, 
or a sensor may not cause a transient response of the airplane's flight 
path any greater than a minor transient, as defined in paragraph (n)(1) 
of this section.
    (d) Under normal conditions, the disengagement of any automatic 
control function of a flight guidance system may not cause a transient 
response of the airplane's flight path any greater than a minor 
transient.
    (e) Under rare normal and non-normal conditions, disengagement of 
any automatic control function of a flight guidance system may not 
result in a transient any greater than a significant transient, as 
defined in paragraph (n)(2) of this section.
    (f) The function and direction of motion of each command reference 
control, such as heading select or vertical speed, must be plainly 
indicated on, or adjacent to, each control if necessary to prevent 
inappropriate use or confusion.
    (g) Under any condition of flight appropriate to its use, the 
flight guidance system may not produce hazardous loads on the airplane, 
nor create hazardous deviations in the flight path. This applies to 
both fault-free operation and in the event of a malfunction, and 
assumes that the pilot begins corrective action within a reasonable 
period of time.
    (h) When the flight guidance system is in use, a means must be 
provided to avoid excursions beyond an acceptable margin from the speed 
range of the normal flight envelope. If the airplane experiences an 
excursion outside this range, a means must be provided to prevent the 
flight guidance system from providing guidance or control to an unsafe 
speed.
    (i) The flight guidance system functions, controls, indications, 
and alerts must be designed to minimize flightcrew errors and confusion 
concerning the behavior and operation of the flight guidance system. 
Means must be provided to indicate the current mode of operation, 
including any armed modes, transitions, and reversions. Selector switch 
position is not an acceptable means of indication. The controls and 
indications must be grouped and presented in a logical and consistent 
manner. The indications must be visible to each pilot under all 
expected lighting conditions.
    (j) Following disengagement of the autopilot, a warning (visual and 
auditory) must be provided to each pilot and be timely and distinct 
from all other cockpit warnings.
    (k) Following disengagement of the autothrust function, a caution 
must be provided to each pilot.
    (l) The autopilot may not create a potential hazard when the 
flightcrew applies an override force to the flight controls.
    (m) During autothrust operation, it must be possible for the 
flightcrew to move the thrust levers without requiring excessive force. 
The autothrust may not create a potential hazard when the flightcrew 
applies an override force to the thrust levers.
    (n) For purposes of this section, a transient is a disturbance in 
the control or flight path of the airplane that is not consistent with 
response to flightcrew inputs or environmental conditions.
    (1) A minor transient would not significantly reduce safety margins 
and would involve flightcrew actions that are well within their 
capabilities. A minor transient may involve a slight increase in 
flightcrew workload or some physical discomfort to passengers or cabin 
crew.
    (2) A significant transient may lead to a significant reduction in 
safety margins, an increase in flightcrew workload, discomfort to the 
flightcrew, or physical distress to the passengers or cabin crew, 
possibly including non-fatal injuries. Significant transients do not 
require, in order to remain within or recover to the normal flight 
envelope, any of the following:
    (i) Exceptional piloting skill, alertness, or strength.
    (ii) Forces applied by the pilot which are greater than those 
specified in Sec.  25.143(c).
    (iii) Accelerations or attitudes in the airplane that might result 
in further hazard to secured or non-secured occupants.

[[Page 18192]]

Sec.  25.1335  [Removed]

0
3. Amend part 25 by removing Sec.  25.1335.

    Issued in Washington, DC, on April 5, 2006.
Marion C. Blakey,
Administrator.
[FR Doc. 06-3467 Filed 4-10-06; 8:45 am]
BILLING CODE 4910-13-P