```

[Federal Register Volume 76, Number 162 (Monday, August 22, 2011)]
[Rules and Regulations]
[Pages 52241-52249]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-21247]

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

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 121

[Docket No.: FAA-2009-0675; Amendment No. 121-356]

RIN 2120-AJ43

Activation of Ice Protection

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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

SUMMARY: This action revises the operating rules for flight in icing 
conditions. For certain airplanes certificated for flight in icing, the 
new standards require either installation of ice detection equipment or 
changes to the airplane flight manual to ensure timely activation of 
the airframe ice protection system. This action is the result of 
information gathered from icing accidents and incidents. It is intended 
to increase the level of safety when airplanes fly in icing conditions.

DATES: This amendment becomes effective October 21, 2011.

FOR FURTHER INFORMATION CONTACT: For operational questions contact 
Charles J. Enders, Air Carrier Operations Branch, AFS-220, Flight 
Standards Service, Federal Aviation Administration, 800 Independence 
Ave., SW., Washington, DC 20591; telephone (202) 493-1422; facsimile 
(202) 267-5229; e-mail Charles.J.Enders@faa.gov.
    For aircraft certification questions contact Robert Jones, 
Propulsion/Mechanical Systems Branch, ANM-112, Transport Airplane 
Directorate, Aircraft Certification Service, Federal Aviation 
Administration, 1601 Lind Avenue, SW., Renton, WA 98057-3356; telephone 
(425) 227-1234; facsimile (425) 227-1149; e-mail 
Robert.C.Jones@faa.gov.
    For legal questions contact Douglas Anderson, Office of Regional 
Counsel, ANM-7, Federal Aviation Administration, 1601 Lind Ave., SW., 
Renton, Washington 98057-3356; telephone (425) 227-2166; facsimile 
(425) 227-1007; e-mail Douglas.Anderson@faa.gov.

SUPPLEMENTARY INFORMATION:

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. Under that section, 
the FAA is charged with prescribing regulations 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 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 operation 
of certain airplanes used in air carrier service.

I. Summary of the Final Action

    The FAA is creating new regulations in Title 14, Code of Federal 
Regulations (14 CFR) part 121 (Operating Requirements: Domestic, Flag, 
and Supplemental Operations) related to the operation of certain 
transport category airplanes in icing conditions. To improve the safety 
of these airplanes operating in icing conditions, the new regulations 
require either installation of ice detection equipment and procedures 
for its use, or changes to the airplane flight manual (AFM) to ensure 
timely activation of the airframe ice protection system.
    The economic evaluation for the final rule shows that the benefits 
exceed the costs for the nominal, seven, and three percent present 
value rates. The estimated benefits are $27.2 million ($16.2 million 
present value). The total estimated costs are $12.7 million ($6.7 
million present value). The following table shows these results.
[GRAPHIC] [TIFF OMITTED] TR22AU11.051

II. Background

    On October 31, 1994, an accident involving an Avions de Transport 
Regional ATR 72 series airplane occurred in icing conditions. This 
prompted the FAA to initiate a review of aircraft safety in icing 
conditions and determine what changes could be made to increase the 
level of safety. In May 1996, we sponsored the International Conference 
on Aircraft Inflight Icing, where icing specialists made 
recommendations for increasing safety. We reviewed these 
recommendations and developed a comprehensive, multi-year icing plan. 
The FAA Inflight Aircraft Icing Plan, dated April 1997,\1\ described 
various activities we were considering for improving aircraft safety in 
icing conditions. In accordance with this plan, we tasked the Aviation 
Rulemaking Advisory Committee (ARAC) to consider the need for ice 
detectors or other means to give flightcrews early indication about 
action required for ice accumulating on critical surfaces of the 
airplane.\2\ The work was carried out by ARAC's Ice Protection 
Harmonization Working Group (IPHWG). Its recommendations may be found 
in the docket for this rulemaking (FAA-2009-0675).
---------------------------------------------------------------------------

    \1\ FAA Inflight Aircraft Icing Plan, dated April 1997, is 
available in the Docket.
    \2\ Published in the Federal Register on December 8, 1997 (62 FR 
64621).
---------------------------------------------------------------------------

A. Summary of the NPRM

    On November 23, 2009, the FAA published a notice of proposed 
rulemaking (NPRM) based on ARAC's recommendations to the FAA (74 FR

[[Page 52242]]

61055). That NPRM proposed changes to the regulations for operators of 
certain airplanes certificated for flight in icing conditions that are 
operated under 14 CFR part 121. It proposed requirements for 
installation of ice detection equipment and/or changes to the AFM to 
ensure timely activation of the airframe ice protection system. The 
comment period for that NPRM closed on February 22, 2010.

B. Definitions

    An appendix to the preamble of this rule gives definitions of the 
terms used here.

C. Related Activity

    The FAA is currently engaged in rulemaking that would require 
operators of airplanes to exit icing conditions for which the airplane 
has not been certified. Supercooled large droplet icing conditions may 
be an example of such conditions.

D. Summary of Comments

    The FAA received 56 comment documents in response to the NPRM. Some 
commenters submitted multiple comments.
     Twenty-two commenters (Boeing, Airbus, the Regional 
Airline Association (RAA), Air Line Pilots Association International 
(ALPA), and 16 private citizens) expressed support for the proposal in 
the NPRM.
     Twenty-nine private citizens offered general comments on 
icing and ice protection that did not specifically address the proposal 
in the NPRM. These commenters stated that the FAA had not done enough, 
early enough, to solve the safety problems of flight in icing 
conditions. Because these comments were beyond the scope of the NPRM's 
proposal, we are not responding to them in this preamble.
     BAE Systems, XCEL Jet Management, the National 
Transportation Safety Board (NTSB), and two private citizens provided 
critical or non-supportive comments to the proposal in the NPRM.

III. Discussion of the Final Rule

    This final rule is identical to the rule proposed in the NPRM. Its 
goal is to ensure that ice protection systems are activated in a timely 
way. It does this by relieving the flightcrew of the need for judging 
when to activate the ice protection system. It gives the flightcrew--
     Primary ice detectors that will alert them to icing,
     Specific visual cues to indicate icing, supplemented by 
advisory ice detectors, or
     Specific air temperatures to check for which, in the 
presence of visible moisture, will indicate conditions conducive to 
icing and the need to follow icing procedures.
    This rule applies to airplanes operating under part 121 rules with 
a certified maximum takeoff weight (MTOW) of less than 60,000 pounds. 
It requires--
    a. A primary ice detection system and appropriate activation 
equipment and procedures to ensure timely activation of the ice 
protection system,
    b. An advisory ice detection system plus substantiated visual cues 
and procedures to ensure timely activation and, if necessary, repeated 
operation of the ice protection system, or
    c. If the airplane is not equipped to comply with either a or b 
above, that flightcrews activate and continuously or cyclically operate 
the ice protection system when in icing conditions during--
     The takeoff climb after second segment,
     En route climb,
     Holding,
     Maneuvering for approach and landing, and
     Any other operation at approach or holding airspeeds.
    Icing conditions will be indicated by a specific air temperature 
and the presence of visible moisture. The flightcrew must operate the 
ice protection at the first sign of ice accumulation for any other 
phases of flight until after exiting the icing conditions. When the ice 
protection system is activated, the flightcrew must also initiate any 
additional procedures for operation in conditions conducive to icing 
specified in the AFM or the manual required by Sec.  121.133. This 
third option of the rule permits compliance without additional 
equipment. It supports part 121 operations of existing airplanes that 
are not equipped with ice detectors and new airplanes designed in 
accordance with Sec.  25.1419(e)(3). However, if the AFM prohibits 
these procedures, then compliance must be demonstrated with either of 
the first two options.
    To eliminate any guesswork for the flightcrew in identifying icing 
conditions, this rule defines icing conditions as the presence of 
visible moisture in temperatures of 5[deg] C or less static air 
temperature or 10[deg] C or less total air temperature, unless the AFM 
defines it differently.
    The rule requires that ice protection procedures be established in 
the AFM or the manual required by Sec.  121.133, and that they 
address--
     Initial activation of the ice protection system,
     Operation of the ice protection system after initial 
activation, and
     Deactivation of the ice protection system.
    These procedures must address whether, after initial activation, 
the ice protection system must be operated continuously or cycled 
automatically or manually. The rule also specifies that if an operator 
elects to install an ice detection system, it must be approved through 
an amended or supplemental type certificate in accordance with part 21.
    The FAA considers this rule to be a necessary increase in the 
standard of safety because there have been accidents and incidents in 
which the flightcrew did not start the airframe ice protection system 
soon enough. In some cases, crews were completely unaware of ice 
accumulation on the airframe. In other cases, they knew that ice was 
accumulating, but thought it not significant enough to require 
activating the ice protection system. This rule is meant to prevent 
that from happening again by giving flightcrews a clear means of 
knowing when to activate the airframe ice protection system. Following 
are the comments requesting changes to the rule.

A. Training

    XCEL Jet Management commented that poor training and airmanship in 
relation to operating in icing conditions were responsible for both the 
Colgan Air \3\ and ATR accidents and that better pilot training was the 
solution. An individual commenter suggested that improved and more 
complete pilot training were the real solutions for reducing icing 
accidents and suggested that pilots should obtain a license endorsement 
for flight in icing. Neither of these commenters felt that this 
additional operating rule was warranted.
---------------------------------------------------------------------------

    \3\ The Colgan Air accident occurred on February 12, 2009, when 
a Bombardier Model DHC-8-400 series airplane flying in icing 
conditions crashed outside of Buffalo, NY, killing 50 people.
---------------------------------------------------------------------------

    While icing conditions were present at the time of the Colgan 
accident, the NTSB did not find that these conditions either caused or 
contributed to the accident. Rather, the NTSB found that Colgan Air's 
inadequate procedures for airspeed selection and management during 
approaches in icing condition contributed to the accident. The Colgan 
Air flightcrew was operating the ice protection system properly, and 
the airplane stall occurred very close to the clean wing stall speed. 
The Bombardier

[[Page 52243]]

Model DHC-8-400 series airplane that those pilots were flying has an 
advisory ice detection system that helped them know when to activate 
the ice protection system. Pilots may fail to activate an ice 
protection system for any number of reasons that could include 
inattention, a heavy workload that causes ice monitoring vigilance to 
be reduced, or failure to detect the ice because of environmental 
conditions. Additional training may not effectively address any of 
those issues. Thus, we proposed a rule that will require either 
actively alerting the pilot to icing conditions or causing the pilot to 
activate the ice protection system when a certain temperature exists in 
conditions of visible moisture. The exception to this would be during 
the cruise phase, when activation of the ice protection system at the 
first sign of icing will be required. This will ensure safe flight in 
icing conditions independent of icing flight training. Therefore, the 
proposed rule is not changed based on these comments.
    Note that many new training materials developed by National 
Aeronautics and Space Administration (NASA) have been released in order 
to ensure that pilots have access to information that will give them 
the knowledge and skills to safely and strategically fly in icing 
conditions.

B. Require Automatic Detection and Activation

    An individual commenter indicated that the ice protection system 
should be turned on automatically but in a ``sequence that would allow 
the crew to turn it off both before it activated and after it completed 
a cycle.''
    We understand from this that the commenter thinks automatic 
activation should be mandatory, but with features that allow the pilot 
to intercede. While automatic activation has advantages, we have not 
determined it should be mandatory. The FAA does not dictate design of 
aircraft systems. Instead we provide performance-based rules. We 
believe it should be up to the operator/applicant to choose the best 
design for its aircraft. Under this approach, an automatic activation 
design would be acceptable. Examples of other safe and acceptable 
options include--
     Primary ice detection with manual ice protection system 
activation,
     Advisory ice detection and pilot monitoring with manual 
ice protection system activation, and
     Manual ice protection system activation based on 
temperature and visible moisture for non-cruise flight phases, as well 
as manual ice protection system activation during cruise at the first 
sign of icing.
    We have not changed the rule based on this comment.

C. Does the rule include withdrawn airworthiness directives (ADs)?

    BAE stated that it is not clear whether the rule applies to 
airplanes for which previously proposed ADs were withdrawn. It is the 
FAA's intent that this new rule will apply to all airplanes with a 
certified MTOW less than 60,000 pounds, whether or not original ADs 
requiring ice protection system activation at the first sign of icing 
have been withdrawn. As discussed in the NPRM, the purpose of the ADs 
was to require that the ice protection system be activated at the first 
sign of icing. This assumes the flightcrew detects the icing. The fact 
that we concluded there was no need to prevent delayed activation on 
certain airplanes, and therefore withdrew those ADs, is irrelevant to 
the purpose of this rule. The purpose of this rulemaking is to ensure 
detection and activation or, if operating without an ice detection 
system, timely activation in non-cruise flight. The FAA also finds 
that, for airplanes not equipped with ice detectors, it is acceptable 
to activate the ice protection system at the first sign of icing for 
any phase not identified in Sec.  121.321(a)(3)(i) (for example, 
cruise).

D. Existing Procedures Are Safe Enough

    BAE stated that original certification of their airplanes for 
flight in icing was based on the most adverse accretions determined 
from Appendix C to part 25, and that the procedures established during 
this certification, including activation after accumulating one-half 
inch of ice on the airframe, do not result in an unsafe condition.
    We agree that following the established procedures does not result 
in an unsafe condition, as long as the flightcrew detects the icing and 
activates the ice protection system in accordance with those 
procedures. But several accidents and incidents have occurred because 
of failure to activate the ice protection system in a timely fashion. 
In some of those cases, critical ice formed before the crew activated 
the ice protection system. Other cases have occurred when, for any 
number of reasons, there was a delay in activating the ice protection 
system. This rule is intended to ensure timely detection of icing on 
the airframe and activation of the ice protection system. It helps 
ensure that ice protection system activation procedures are followed. 
Therefore, the proposed rule is not changed based on this comment.

E. Residual and Intercycle Ice

    BAE suggested that the larger ice accretions assessed during 
certification might be safer than ice accumulated when operating the 
ice protection system in conditions conducive to icing, at the first 
sign of icing, and at regular intervals thereafter. BAE also expressed 
concern that aircraft handling qualities and performance have not been 
demonstrated with these new procedures. BAE does not recommend 
acceptance of this rule in its current form unless we can provide 
further justification for its adoption.
    We believe there is ample justification for this rule. In the 
initial stages of the IPHWG's examination of the problems of flight in 
icing, there was great concern about activating boot ice protection 
systems at the first sign of icing because of a phenomenon known as ice 
bridging.\4\ We infer this is the reason BAE suggested larger ice 
accretions may be safer than those that would be formed under this 
rule. No one has reported ice bridging nor has it been seen during 
testing on modern deicing boots. Classical ice bridging was associated 
with older designs that had slow inflation and deflation rates; on the 
order of ten seconds. Modern systems, with their small-diameter 
inflation chambers and high inflation rates, ensure that bridging is 
not a concern. We also infer from this comment a concern that residual 
and intercycle ice might be more critical than allowing a certain depth 
of ice to accrete before ice protection system activation. This concern 
is limited to booted ice protection systems.
---------------------------------------------------------------------------

    \4\ Ice bridging is a phenomenon that may have occurred on some 
obsolete de-icing boot systems. In theory, ice could form around the 
outside of a fully inflated boot, forming a ``bridge,'' which then 
could not be removed by subsequent inflation cycles of the boot.
---------------------------------------------------------------------------

    Persistent ice accretions occur in icing conditions even when 
pneumatic deicing boots are operating. Whether one-quarter or one-half 
inch of ice is allowed to accumulate before activation, or the icing 
boots are activated at the first sign of ice accumulation, or they are 
activated at annunciation by an ice detector system and periodically 
afterwards, residual and intercycle ice will exist. The procedure will 
minimize residual and intercycle ice accretions because the ice will 
shed when the minimum thickness or mass required for shedding is 
reached. Adverse airplane flying qualities resulting from ice 
accretions typically are affected by the thickness, shape, texture, and 
location of the ice. The thickness of the residual and intercycle ice 
resulting from this

[[Page 52244]]

procedure is less than what is typically allowed to accumulate before 
deicing boot operation when the manufacturer has recommended delayed 
activation.
    The FAA has written many ADs requiring airplane operators to 
include in their AFM procedures to activate deicing boots at the first 
sign of ice accumulation. The airplane models to which these ADs were 
directed have many different wing and stabilizer design characteristics 
and different deicing boot configurations. In addition, they represent 
a large proportion of the airplane fleet that is equipped with 
pneumatic deicing boots. We have not received any reports of these 
airplanes suffering adverse effects of ice from early activation of the 
deicing boots.
    In addition, a number of airplane models are equipped with deicing 
boot systems with automatic operating modes. These systems 
automatically cycle at specific time intervals after being initially 
activated. Such automatic cycling has certainly resulted in operation 
of the boots with less than the recommended thickness of ice accretion 
originally included in the AFMs. We have received no reports indicating 
any adverse effects from use of the automatic mode. Boot ice protection 
systems operated early and often to remove ice, including intercycle 
and residual ice, have performed safely and effectively. We have not 
changed the rule based on this comment.

F. Additional Certification Will Be Necessary

    BAE noted that crews operating under Sec.  121.321(a)(3) (without 
ice detectors) need to activate the ice protection system in conditions 
conducive to icing irrespective of whether ice is actually accreting. 
For aircraft that do not have an automatic mode to cycle the ice 
protection system, the continuous manual cycling of the system would 
result in an increased workload for the flightcrew. Section 
121.321(d)(iv) requires that, for airplanes without automatic cycling 
modes, procedures will be needed for a specific time interval for 
repeated cycling of the ice protection system. BAE said that validation 
of this procedure could require further icing certification testing, 
and that this issue had not been raised in the NPRM.
    With respect to increasing workload, currently pilots have to 
monitor for ice. Sometimes in these conditions it may be difficult to 
determine whether activation of the ice protection system is needed. 
This final rule requires that, after initial activation of the ice 
protection system, the pilot periodically activate the ice protection 
system. To do this, the pilot only has to monitor time, not ice 
accretion thickness. Therefore, we do not believe there will be any 
significant increase in workload, and that the workload may decrease in 
some circumstances.
    With respect to BAE's comment that validating ice protection system 
cycling procedures and the potential for icing certification testing 
was not raised in the NPRM, every airplane that uses a manual deicing 
system has established procedures for its operation until the airplane 
has exited icing conditions. Models with periodic cycling procedures 
should require no incremental certification testing because they 
already have an approved periodic cycling procedure. For airplanes in 
which flightcrews have in the past activated boots based on ice 
accretion thickness, calculating a conservative cycling interval based 
on Appendix C to part 25 is a relatively straightforward process. It 
should not require flight testing. In addition, AC 121.321-X provides 
guidance recommending that intervals should not exceed three minutes. 
Thus, we do not believe that validation of this procedure should 
require additional certification testing.

G. Include All Airplanes

    The NTSB expressed support for the proposed rule. However, the NTSB 
stated that the rule should apply to all deicing-boot-equipped 
airplanes currently in service. This would include airplanes weighing 
more than 60,000 pounds. The NTSB also suggested that the Bombardier 
Model DHC-8-400 series airplane (which has a MTOW of slightly more than 
60,000 pounds and was involved in the Colgan Air accident) might have 
been better protected if this rule had been applied to it.
    The FAA appreciates the NTSB's support for the proposed rule. We do 
not believe, however, that it is necessary to expand the rule to cover 
airplanes with higher weights. The IPHWG data and analysis showed that 
only airplanes falling below the weight level in the rule have had 
problems associated with delayed activation of the ice protection 
system.
    As for the Bombardier Model DHC-8-400 series airplane, while icing 
conditions were present at the time of the Colgan accident, the NTSB 
did not find that these conditions either caused or contributed to the 
accident. Rather, the NTSB found that Colgan Air's inadequate 
procedures for airspeed selection and management during approaches in 
icing condition contributed to the accident. In fact, the accident 
airplane had an ice detector and would have been in compliance with 
this rule through the majority of its flight profile. Therefore, 
increasing the maximum applicable weight to capture the Bombardier 
Model DHC-8-400 series airplane would have very little, if any, safety 
benefit. Increasing the rule's weight applicability to encompass other 
airplanes of this size and larger is not justified by available data. 
We have not changed the rule as a result of this comment.
    Another reason the NTSB suggested that the rule should encompass 
heavier airplanes is that it believes such procedures would also help 
protect these airplanes in conditions that fall outside of Appendix C 
to part 25. This rule does not address conditions outside of Appendix 
C. In supercooled large droplet (SLD) conditions (which are not 
included in Appendix C), ice may form aft of the ice protection system 
equipment. To suggest that this rule may help address the SLD issue is 
not correct. The most significant item to consider, however, is that 
data show that these heavier airplanes have not had any safety problems 
associated with delayed activation of the ice protection system. 
Therefore, the rule is not changed as a result of this comment.

H. Include Parts 91 and 135 Operations

    The NTSB supported applying the proposed rule to airplanes operated 
under part 121, but stated that a similar rule should also be levied on 
all airplanes operated under 14 CFR parts 91 and 135. The NTSB stated 
that on parts 91 and 135 airplanes with ADs directing flightcrews to 
activate the ice protection system at the first sign of icing, it can 
be difficult for crews to identify icing on the airplanes. The NTSB 
noted that a Circuit City Citation Model 560 series airplane involved 
in an icing accident was operated under part 91 and had an AD for 
activation of deicing boots at the first sign of icing, which had been 
withdrawn. This left the flightcrew to observe a prescribed amount of 
ice before activation. The NTSB believed that similar accidents may 
occur if parts 91 and 135 airplanes are not included in this rule.
    We considered including parts 91 and 135 operations during 
deliberations of the IPHWG and during drafting of the NPRM. We 
determined, however, that the increased flexibility afforded by 
unscheduled operations (the types of operations governed by parts 91 
and 135), coupled with appropriate direction on when pilots should 
activate the ice protection systems (usually at the first sign of icing 
or in conditions of visible moisture and specific temperatures), 
provides an adequate

[[Page 52245]]

level of safety for ice protection system activation. Pilots flying 
scheduled operations, on the other hand, may not have the flexibility 
to avoid flying into weather that would otherwise be avoided. This rule 
ensures that part 121 operators of applicable airplanes will be 
directed to operate the ice protection systems appropriately.
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. According to the 1995 
amendments to the Paperwork Reduction Act (5 CFR 1320.8(b)(2)(vi)), an 
agency may not collect or sponsor the collection of information, nor 
may it impose an information collection requirement unless it displays 
a currently valid Office of Management and Budget (OMB) control number.
    This final rule will impose the following new information 
collection requirements. As required by the Paperwork Reduction Act of 
1995 (44 U.S.C. 3507(d)), the FAA has submitted these proposed 
information collection amendments to OMB for its review.
    This final rule requires--
    a. A primary ice detection system and appropriate activation 
equipment and procedures to ensure timely activation of the ice 
protection system,
    b. An advisory ice detection system plus substantiated visual cues 
and procedures to ensure timely activation and, if necessary, repeated 
operation of the ice protection system, or
    c. If the airplane is not equipped to comply with either a or b 
above, that flightcrews activate and continuously or cyclically operate 
the ice protection system when in icing conditions during--
     The takeoff climb after second segment,
     En route climb,
     Holding,
     Maneuvering for approach and landing, and
     Any other operation at approach or holding airspeeds.
    This rule may require operators to revise their airplane flight 
manuals or the manual required by Sec.  121.133. Adding these new 
procedures may require the addition of a page or two to those manuals. 
This is classified as a record keeping item and no data will be 
collected.
    We have received no comments about the recordkeeping burden of this 
rule. The OMB control number for this information collection will be 
published in the Federal Register after the Office of Management and 
Budget approves it.
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 regulations.

IV. 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 Agreements Act requires agencies to consider 
international standards and, where appropriate, that they be the basis 
of U.S. standards. Fourth, the Unfunded Mandates Reform Act of 1995 
(Pub. L. 104-4) requires agencies to prepare a written assessment of 
the costs, benefits, and other effects of proposed or final rules that 
include a Federal mandate likely to result in the expenditure by State, 
local, or Tribal governments, in the aggregate, or by the private 
sector, of $100 million or more annually (adjusted for inflation with 
base year of 1995). This portion of the preamble summarizes the FAA's 
analysis of the economic impacts of this final rule. Readers seeking 
greater detail should read the full regulatory evaluation, a copy of 
which we have placed in the docket for this rulemaking.
    In conducting these analyses, FAA has determined that this final 
rule: (1) Has benefits that justify its costs; (2) is not an 
economically ``significant regulatory action'' as defined in section 
3(f) of Executive Order 12866; (3) has been designated as a 
``significant regulatory action'' by the Office of Management and 
Budget, and is therefore ``significant'' under DOT's Regulatory 
Policies and Procedures; (4) will not have a significant economic 
impact on a substantial number of small entities; (5) will not create 
unnecessary obstacles to the foreign commerce of the United States; and 
(6) will not impose an unfunded mandate on State, local, or Tribal 
governments, or on the private sector by exceeding the threshold 
identified above. These analyses are summarized below.

Total Benefits and Costs of This Rule

    The estimated cost of this final rule is about $12.7 million in 
nominal dollars ($6.7 million in seven percent present value terms). 
The estimated potential benefits of averting one accident and five 
fatalities are about $22.1 million in nominal dollars ($11.4 million in 
seven percent present value terms). Table 1 shows these results.
[GRAPHIC] [TIFF OMITTED] TR22AU11.052

[[Page 52246]]

Who is potentially affected by this rule?

    Operators of transport category airplanes with a certified MTOW 
under 60,000 pounds operating under 14 CFR part 121.

Assumptions

    (1) The base year is 2010.
    (2) This final rule will be effective in 2011.
    (3) The compliance date of the rule is 24 months from the effective 
date of the final rule.
    (4) The analysis period extends for 20 years from 2013 through 
2032. We believe this analysis period captures nearly all of the 
expected benefits and costs.
    (5) All monetary values are expressed in constant 2010 dollars. The 
present value of the potential 10-year benefit stream was calculated by 
discounting the monetary values using three and seven percent present 
value rates over the 2013 to 2032 analysis period.
    (6) The value of an averted fatality is $6.0 million.\5\
---------------------------------------------------------------------------

    \5\ ``Treatment of the Economic Value of a Statistical Life in 
Departmental Analysis,'' March 18, 2009, U.S. Department of 
Transportation Memorandum.
---------------------------------------------------------------------------

    (7) The FAA used a $104.99 hourly rate for a mechanic/technician 
working for an airplane manufacturer or modifier and an $86.48 hourly 
rate for an engineer working for an airplane manufacturer or modifier. 
These hourly rates include overhead costs.\6\
---------------------------------------------------------------------------

    \6\ Department of Labor, Bureau of Labor Statistics. 
Occupational Employment and Wages.
---------------------------------------------------------------------------

Benefits of This Rule

    The benefits of this final rule consist of the value of averted 
fatalities, airplane loss, and investigation cost from avoiding 
accidents involving transport category airplanes with a certified MTOW 
under 60,000 pounds operating under 14 CFR part 121. We estimate that 
one accident and five fatalities could potentially be avoided, over the 
analysis period, by adopting the final rule. The value of an averted 
fatality is assumed to be $6.0 million. A series of Airworthiness 
Directives (ADs) were issued for airplanes with pneumatic de-icing 
boots to activate the systems at the first sign of ice accretion. Due 
to the similarity of requirements between the ADs and this proposal, we 
accounted for the effects of the ADs by reducing the estimated 
benefits. Over the analysis period, the potential benefits of the final 
rule will be $22.1 million in nominal dollars ($11.4 million in seven 
percent present value terms).

Estimated Costs of This Rule

    We estimate the total cost of the final rule, over the analysis 
period, to be about $12.7 million in nominal dollars using airplane 
compliance costs developed by the IPHWG. The seven percent present 
value cost of this final rule over the analysis period is about $6.7 
million. We estimate the initial costs for a new certification program 
for operating the deicing boots based on visible moisture and 
temperature are about $400,000. We estimate the operating and training 
costs are about $12.3 million.

Alternatives Considered

Alternative One
    Maintain the status quo: Simply maintaining the status quo for 
flight in icing procedures would not be a practice that is responsive 
to NTSB recommendations and the FAA Inflight Aircraft Icing Plan. The 
FAA has rejected this alternative because the final rule will enhance 
passenger safety and prevent ice-related accidents for airplanes with a 
certified MTOW less than 60,000 pounds. As it stands, the final rule is 
the reasoned result of the FAA Administrator carrying out the FAA 
Inflight Aircraft Icing Plan.
Alternative Two
    Issue more ADs requiring a means to know when to activate the icing 
protection system: The FAA has already issued ADs to address activation 
of icing protection systems. An evaluation of accidents and incidents 
led to the conclusion that the ADs do not provide adequate assurance 
that the flightcrew will be made aware of when to activate the icing 
protection system. Because this problem is not unique to particular 
airplane designs, but exists for all airplanes susceptible to the icing 
hazards described previously, it is appropriate to address this problem 
through an operational rule, rather than by ADs.
Alternative Three
    Issue new standards: The third alternative is this final rule. The 
FAA's judgment is that this is the most viable option because the final 
rule will increase the safety of the flying public by reducing icing-
related accidents in the future in the least costly way.

Regulatory Flexibility Determination

    The Regulatory Flexibility Act of 1980 (Pub. L. 96-354) (RFA) 
establishes ``as a principle of regulatory issuance that 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.
    The FAA has determined that this final rule will not have a 
significant economic impact on a substantial number of small entities. 
The FAA made the same determination in the NPRM. There were no comments 
regarding small entities for the NPRM.
    The following briefly describes the history leading up to this 
rulemaking and the methodology used to determine that this final rule 
will not have a significant economic impact on a substantial number of 
small entities.
    On October 31, 1994, at 1559 Central Standard Time, an Avions de 
Transport Regional model ATR 72, operated by Simmons Airlines, 
Incorporated, and doing business as American Eagle flight 4184, crashed 
during a rapid descent after an uncommanded roll excursion. The FAA, 
Aerospatiale, the French Direction G[eacute]n[eacute]rale de l'Aviation 
Civile, Bureau Enquete Accident, NASA, NTSB, and others conducted an 
extensive investigation of this accident.
    This accident and the investigation prompted the FAA to initiate a 
review of aircraft inflight icing safety and determine changes that 
could be made to increase the level of safety. The final rule is 
responsive to NTSB recommendation A-07-14. The final rule is also one 
of the items listed in the FAA Inflight Aircraft Icing Plan, dated 
April 1997. The Inflight Aircraft Icing Plan details the FAA's plans 
for improving the safety of airplanes when they are operated in icing 
conditions.
    This final rule specifically applies to part 121 operators of 
airplanes that have a certified MTOW of less than 60,000 pounds. We 
have determined which small entities could be affected by associating 
airplanes with a certified MTOW of less than 60,000 pounds with part 
121 operators. For this section of the analysis, only those operators 
meeting the above criteria that have

[[Page 52247]]

1,500 or fewer employees are considered.
    To estimate the number of affected airplanes, the FAA analyzed the 
current active fleet of airplanes, a forecast of airplanes affected by 
the final rule entering the fleet, and a forecast of the retired 
affected airplanes exiting the fleet during the analysis period.
    A list of all U.S. operated civilian airplanes operating under part 
121 was generated by the FAA Flight Standards Service. Each airplane 
group was matched with its current (as of May 2010) MTOW and average 
age through the use of the OAG FleetPCTM database. All 
airplanes with a MTOW greater than 60,000 pounds were eliminated.
    Using industry sources, the FAA determined which airplanes 
currently had primary or advisory icing detection systems. Airplanes 
equipped with either a primary or advisory ice detection system are in 
compliance, and this final rule will impose no costs to operators of 
those airplanes. All turbojets affected by this proposal are in 
compliance because those airplanes are equipped with either a 
certificated primary or advisory ice detection systems.
    The FAA used the OAG FleetPCTM database and determined 
that turboprops are retired from U.S. certificated service at an 
average age (mean) of 25.9 years. Thus, we assume that each of the 
small operators' airplanes is retired when their airplanes reach the 
average retirement age of 25.9 years.
    Using information provided by the World Aviation Directory, SEC 
filings, and the Internet, scheduled and non-scheduled commercial 
operators that are subsidiary businesses of larger businesses were 
eliminated from the database. An example of a subsidiary business is 
Continental Express, Inc., which is a subsidiary of Continental 
Airlines. Using information provided by the U.S. Department of 
Transportation Form 41 filings, the World Aviation Directory Winter 
2009, and the Internet, all businesses with more than 1,500 employees 
were eliminated. The FAA obtained company revenue from the remaining 
businesses. Following this approach, five small entities operate 
airplanes that will be affected by this proposal.
    The FAA estimated the cost of compliance per airplane and 
multiplied this cost by the total fleet of affected airplanes per 
operator, over the analysis period, to obtain the total compliance cost 
for each small entity. The non-recurring costs, for updating the 
airplane flight manual for each major airplane group, were distributed 
equally among the airplanes in each major airplane group. These non-
recurring costs occurred in year four of the analysis period. Note that 
the more airplanes in a major airplane group, the less expensive, per 
airplane, the non-recurring costs are to the operators of those 
airplanes. In addition to the airplane flight manual cost, the 
additional incremental recurring costs include boot maintenance, 
replacement and installation labor. These recurring costs started in 
2013 and continued either until the airplane retired or through the end 
of the analysis period.
    The degree to which small air operator entities can ``afford'' the 
cost of compliance is determined by the availability of financial 
resources. The initial implementation costs of the final rule may be 
financed, paid for using existing company assets, or borrowed. A proxy 
for the firm's ability to afford the cost of compliance is the ratio of 
the total annualized cost of the final rule as a percentage of annual 
revenue. No small business operator potentially affected by this final 
rule incurred costs greater than one percent of its annual revenue. On 
that basis, we believe firms can afford the compliance costs of this 
final rule. We used a similar metric for the initial regulatory 
flexibility analysis and received no comments. Table 2 shows the 
economic impact on the small entity air operators affected by this 
final rule.
[GRAPHIC] [TIFF OMITTED] TR22AU11.053

    Therefore as the FAA Administrator, 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 (Pub. L. 96-39), as amended by the 
Uruguay Round Agreements Act (Pub. L. 103-465), prohibits Federal 
agencies from establishing standards or engaging in related activities 
that create unnecessary obstacles to the foreign commerce of the United 
States. Pursuant to these Acts, the

[[Page 52248]]

establishment of standards is not considered an unnecessary obstacle to 
the foreign commerce of the United States, so long as the standard has 
a legitimate domestic objective, such the protection of safety, and 
does 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 has assessed the potential effect of this final rule 
and determined that the proposed standards are necessary for aviation 
safety and will not create unnecessary obstacles to the foreign 
commerce of the United States.

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 $143.1 million in lieu of $100 
million. This final rule does not contain such a mandate; therefore, 
the requirements of Title II of the Act do not apply.

Executive Order 13132, Federalism

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

Regulations Affecting Intrastate Aviation in Alaska

    Section 1205 of the FAA Reauthorization Act of 1996 (110 Stat. 
3213) requires the FAA, when modifying its 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, 
while it is considered a ``significant regulatory action'' under DOT's 
Regulatory Policies and Procedures, it is not likely to have a 
significant adverse effect on the supply, distribution, or use of 
energy.

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 notice, amendment, or docket number of this 
rulemaking.
    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 
http://DocketsInfo.dot.gov.

Small Business Regulatory Enforcement Fairness Act

    The Small Business Regulatory Enforcement Fairness Act (SBREFA) of 
1996 requires 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 your local FAA official, or 
the person listed under the FOR FURTHER INFORMATION CONTACT heading at 
the beginning of the preamble. You can find out more about SBREFA on 
the Internet at http://www.faa.gov/regulations_policies/rulemaking/sbre_act/.

Appendix--Definition of Terms Used in This Rule

    For purposes of this final rule, the following definitions are 
applicable. Note that some of these definitions are common to those 
used in the preamble to the final rule for Sec.  25.1419 Ice 
protection, and that rule's accompanying guidance material.
    a. Advisory ice detection system--A system that advises the 
flightcrew of the presence of ice accretion or icing conditions. 
Both primary ice detection systems and advisory ice detection 
systems can either direct the pilot to manually activate the ice 
protection system or provide a signal that automatically activates 
the ice protection system. However, because it has lower reliability 
than a primary system, an advisory ice detection system can only be 
used in conjunction with other means (most commonly, visual 
observation by the flightcrew) to determine the need for, or timing 
of, activating the anti-icing or deicing system. With an advisory 
ice detection system, the flightcrew is responsible for monitoring 
icing conditions or ice accretion as defined in the airplane flight 
manual (AFM), typically using total air temperature and visible 
moisture criteria or visible ice accretion. With an advisory ice 
detection system, the flightcrew is responsible for activating the 
anti-icing or deicing system(s).
    b. Airframe icing--Ice accretion on the airplane, except for on 
the propulsion system.
    c. Anti-icing--Prevention of ice accretions on a protected 
surface, either by:
     Evaporating the impinging water, or
     Allowing the impinging water to run back and off the 
protected surface or freeze on non-critical areas.
    d. Automatic cycling mode--A mode of operation of the airframe 
de-icing system that provides repetitive cycles of the system 
without the need for the pilot to select each cycle. This is 
generally done with a timer, and there may be more than one timing 
mode.
    e. Conditions conducive to airframe icing--Visible moisture at 
or below a static air temperature of 5[deg]C or total air 
temperature of 10[deg]C, unless otherwise substantiated.
    f. Deicing--The removal or the process of removal of an ice 
accretion after it has formed on a surface.

[[Page 52249]]

    g. Ice protection system (IPS)--A system that protects certain 
critical aircraft parts from ice accretion. To be an approved 
system, it must satisfy the requirements of Sec.  23.1419 or Sec.  
25.1419 and other applicable requirements.
    h. Primary ice detection system--A detection system used to 
determine when the IPS must be activated. This system announces the 
presence of ice accretion or icing conditions, and it may also 
provide information to other aircraft systems. A primary automatic 
system automatically activates the anti-icing or deicing IPS. A 
primary manual system requires the flightcrew to activate the anti-
icing or deicing IPS upon indication from the primary ice detection 
system.
    i. Reference surface--The observed surface used as a reference 
for the presence of ice on the monitored surface. The reference 
surface may be observed directly or indirectly. Ice must occur on 
the reference surface before--or at the same time as--it appears on 
the monitored surface. Examples of reference surfaces include 
windshield wiper blades or bolts, windshield posts, ice evidence 
probes, the propeller spinner, and the surface of ice detectors. The 
reference surface may also be the monitored surface.
    j. Static air temperature--The air temperature that would be 
measured by a temperature sensor that is not in motion in relation 
to that air. This temperature is also referred to in other documents 
as ``outside air temperature,'' ``true outside temperature,'' or 
``ambient temperature.''
    k. Total air temperature--The static air temperature plus the 
rise in temperature due to the air being brought to rest relative to 
the airplane.
    l. Visual cues--Ice accretion on a reference surface that the 
flightcrew observes. The visual cue is used to detect the first sign 
of airframe ice accretion.

List of Subjects in 14 CFR Part 121

    Aircraft, Air carriers, Aviation safety, Safety, Reporting and 
recordkeeping requirements.

The Amendment

    In consideration of the foregoing, the Federal Aviation 
Administration amends part 121 of title 14, Code of Federal Regulations 
as follows:

PART 121--OPERATING REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL 
OPERATIONS

0
1. The authority citation for part 121 continues to read as follows:

    Authority:  49 U.S.C. 106(g), 40113, 40119, 44101, 44701-44702, 
44705, 44709-44711, 44713, 44716-44717, 44722, 44901, 44903-44904, 
44912, 46105.

0
2. Revise Sec.  121.321 to read as follows:

Sec.  121.321  Operations in Icing.

    After October 21, 2013 no person may operate an airplane with a 
certificated maximum takeoff weight less than 60,000 pounds in 
conditions conducive to airframe icing unless it complies with this 
section. As used in this section, the phrase ``conditions conducive to 
airframe icing'' means visible moisture at or below a static air 
temperature of 5[deg]C or a total air temperature of 10[deg]C, unless 
the approved Airplane Flight Manual provides another definition.
    (a) When operating in conditions conducive to airframe icing, 
compliance must be shown with paragraph (a)(1), or (2), or (3) of this 
section.
    (1) The airplane must be equipped with a certificated primary 
airframe ice detection system.
    (i) The airframe ice protection system must be activated 
automatically, or manually by the flightcrew, when the primary ice 
detection system indicates activation is necessary.
    (ii) When the airframe ice protection system is activated, any 
other procedures in the Airplane Flight Manual for operating in icing 
conditions must be initiated.
    (2) Visual cues of the first sign of ice formation anywhere on the 
airplane and a certificated advisory airframe ice detection system must 
be provided.
    (i) The airframe ice protection system must be activated when any 
of the visual cues are observed or when the advisory airframe ice 
detection system indicates activation is necessary; whichever occurs 
first.
    (ii) When the airframe ice protection system is activated, any 
other procedures in the Airplane Flight Manual for operating in icing 
conditions must be initiated.
    (3) If the airplane is not equipped to comply with the provisions 
of paragraph (a)(1) or (2) of this section, then the following apply:
    (i) When operating in conditions conducive to airframe icing, the 
airframe ice protection system must be activated prior to, and operated 
during, the following phases of flight:
    (A) Takeoff climb after second segment,
    (B) En route climb,
    (C) Go-around climb,
    (D) Holding,
    (E) Maneuvering for approach and landing, and
    (F) Any other operation at approach or holding airspeeds.
    (ii) During any other phase of flight, the airframe ice protection 
system must be activated and operated at the first sign of ice 
formation anywhere on the airplane, unless the Airplane Flight Manual 
specifies that the airframe ice protection system should not be used or 
provides other operational instructions.
    (iii) Any additional procedures for operation in conditions 
conducive to icing specified in the Airplane Flight Manual or in the 
manual required by Sec.  121.133 must be initiated.
    (b) If the procedures specified in paragraph (a)(3)(i) of this 
section are specifically prohibited in the Airplane Flight Manual, 
compliance must be shown with the requirements of paragraph (a)(1) or 
(2) of this section.
    (c) Procedures necessary for safe operation of the airframe ice 
protection system must be established and documented in:
    (1) The Airplane Flight Manual for airplanes that comply with Sec.  
121.321(a)(1) or (2), or
    (2) The Airplane Flight Manual or in the manual required by Sec.  
121.133 for airplanes that comply with Sec.  121.321(a)(3).
    (d) Procedures for operation of the airframe ice protection system 
must include initial activation, operation after initial activation, 
and deactivation. Procedures for operation after initial activation of 
the ice protection system must address--
    (1) Continuous operation,
    (2) Automatic cycling,
    (3) Manual cycling if the airplane is equipped with an ice 
detection system that alerts the flightcrew each time the ice 
protection system must be cycled, or
    (4) Manual cycling based on a time interval if the airplane type is 
not equipped with features necessary to implement (d)(i)-(iii) of this 
section.
    (e) System installations used to comply with Sec.  121.321(a)(1) or 
(2) must be approved through an amended or supplemental type 
certificate in accordance with part 21 of this chapter.

    Issued in Washington, DC, on August 11, 2011.
J. Randolph Babbitt,
Administrator.
[FR Doc. 2011-21247 Filed 8-19-11; 8:45 am]
BILLING CODE 4910-13-P
```