38328 Federal Register / Vol. 74, No. 147 / Monday, August 3, 2009 / Rules and Regulations 

1This accident and an Empressa Brasilia accident 

resulted in NTSB recommendations nos. A–96–56 

and A–98–91. This final rule partially addresses 

these safety recommendations. 

2FAA Inflight Aircraft Icing Plan, dated April 

1997, available in the Docket. 

3Published in the Federal Register, December 8, 

1997 (62 FR 64621). 

§ 26.41 Audits and corrective action. 

* * * * * 

(d) * * * 

(1) The contracts of licensees and 

other entities with C/Vs and HHScertified laboratories must reserve the 

right to audit the C/V, the C/V’s 

subcontractors providing FFD program 

services, and the HHS-certified 

laboratories at any time, including at 

unannounced times, as well as to review 

all information and documentation that 

is reasonably relevant to the audits. 

* * * * * 

■ 4. In § 26.69, paragraphs (c)(3) and 

(d)(2) are revised to read as follows: 

§ 26.69 Authorization with potentially 

disqualifying fitness-for-duty information. 

* * * * * 

(c) * * * 

(3) If the designated reviewing official 

determines that a determination of 

fitness is required, verify that a 

professional with the appropriate 

qualifications, as specified in 

§ 26.189(a), has indicated that the 

individual is fit to safely and 

competently perform his or her duties; 

* * * * * 

(d) * * * 

(2) If the designated reviewing official 

concludes that a determination of 

fitness is required, verify that a 

professional with the appropriate 

qualifications, as specified in 

§ 26.189(a), has indicated that the 

individual is fit to safely and 

competently perform his or her duties; 

and 

* * * * * 

■ 5. In § 26.137, paragraphs (d)(2)(i), 

(d)(5), and (e)(6)(v) are revised to read 

as follows: 

§ 26.137 Quality assurance and quality 

control. 

* * * * * 

(d) * * * 

(2) * * * 

(i) Colorimetric pH tests must have a 

dynamic range of 2 to 12 and pH meters 

must be capable of measuring pH to one 

decimal place. 

* * * * * 

(5) Each analytical run performed to 

conduct initial validity testing shall 

include at least one quality control 

sample that appears to be a donor 

specimen to the licensee testing facility 

technicians. 

* * * * * 

(e) * * * 

(6) * * * 

(v) At least one positive control, 

certified to be positive by an HHScertified laboratory, which appears to be 

a donor specimen to the licensee testing 

facility technicians. 

* * * * * 

■ 6. In § 26.153, paragraph (f)(3) is 

revised to read as follows: 

§ 26.153 Using certified laboratories for 

testing urine specimens. 

* * * * * 

(f) * * * 

(3) The laboratory shall maintain test 

records in confidence, consistent with 

the requirements of § 26.37, and use 

them with the highest regard for 

individual privacy. 

* * * * * 

Dated at Rockville, Maryland, this 27th day 

of July 2009. 

For the Nuclear Regulatory Commission. 

Annette L. Vietti-Cook, 

Secretary of the Commission. 

[FR Doc. E9–18364 Filed 7–31–09; 8:45 am] 

BILLING CODE 7590–01–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 25 

[Docket No.: FAA–2007–27654; Amendment 

No. 25–129] 

RIN 2120–AI90 

Activation of Ice Protection 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Final rule. 

SUMMARY: The Federal Aviation 

Administration amends the 

airworthiness standards applicable to 

transport category airplanes certificated 

for flight in icing conditions. The rule 

requires a means to ensure timely 

activation of the airframe ice protection 

system. This rule is the result of 

information gathered from a review of 

icing accidents and incidents, and will 

improve the level of safety for new 

airplane designs for operations in icing 

conditions. 

DATES: This amendment becomes 

effective September 2, 2009. 

FOR FURTHER INFORMATION CONTACT: For 

technical questions concerning this final 

rule contact Kathi Ishimaru, FAA, 

Propulsion and Mechanical Systems 

Branch, ANM–112, Transport Airplane 

Directorate, Aircraft Certification 

Service, 1601 Lind Ave., SW., Renton, 

Washington 98057–3356; telephone 

(425) 227–2674; fax: (425) 227–1320, email: kathi.ishimaru@faa.gov. For legal 

questions concerning this final rule 

contact Douglas Anderson, FAA, Office 

of Regional Counsel, Federal Aviation 

Administration, 1601 Lind Ave., SW., 

Renton, Washington 98057–3356; 

telephone (425) 227–2166; fax: (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, ‘‘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. This regulation is within the 

scope of that authority because it 

prescribes new safety standards for the 

design of transport category airplanes. 

I. Background 

On October 31, 1994, an accident 

involving an Avions de Transport 

Regional ATR 72 series airplane 

occurred in icing conditions.1 This 

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. In May 

1996, the FAA sponsored the 

International Conference on Aircraft 

Inflight Icing where icing specialists 

recommended improvements to increase 

the level of safety of aircraft operating 

in icing conditions. The FAA reviewed 

the conference recommendations and 

developed a comprehensive multi-year 

icing plan. The FAA Inflight Aircraft 

Icing Plan (Icing Plan), dated April 

1997,2 described various activities the 

FAA was contemplating to improve 

safety when operating in icing 

conditions. In accordance with the Icing 

Plan, the FAA tasked the Aviation 

Rulemaking Advisory Committee 

(ARAC),3 through its Ice Protection 

Harmonization Working Group, to 

consider the need for ice detectors or 

other acceptable means to warn 

flightcrews of ice accretion on critical 

surfaces requiring crew action. This rule 


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4See Docket No. FAA–2005–22840 for complete 

details. 

5The three methods are: (1) Primary ice detection 

system, (2) visual cues of the first sign of ice 

accretion combined with an advisory ice detector, 

and (3) specifying conditions conducive to airframe 

icing. 

6The full text of each commenter’s submission is 

available in the Docket. 

is based on ARAC’s recommendations to 

the FAA. 

A. Summary of the NPRM 

The notice of proposed rulemaking 

(NPRM), Notice No. 07–07, published in 

the Federal Register on April 26, 2007 

(72 FR 20924), is the basis for this 

amendment. The comment period 

closed July 25, 2007. In the NPRM, we 

proposed to revise the airworthiness 

standards for type certification of 

transport category airplanes to add 

requirements to ensure the timely 

activation of an airframe ice protection 

system (IPS). We also proposed to add 

requirements to reduce the flightcrew 

workload associated with operation of 

an airframe IPS that is manually cycled, 

and to ensure the Airplane Flight 

Manual includes IPS procedures for 

operation. 

B. Summary of the Final Rule 

The FAA is adopting this final rule 

because accidents and incidents 

occurred where the flightcrew did not 

operate the airframe IPS in a timely 

manner and because of concerns over 

the flightcrew workload required to 

operate an airframe IPS that the 

flightcrew must manually cycle when 

they observe ice accretions. The final 

rule addresses these concerns by 

ensuring that flightcrews are provided 

with a clear means to know when to 

activate the airframe IPS. The final rule 

reduces the workload associated with 

monitoring ice accretions by requiring a 

system that operates continuously, a 

system that automatically cycles the 

IPS, or an alert to the flighcrew each 

time the IPS must be cycled. 

This final rule adopts the proposed 

rule with minor changes and adds 

minor conforming changes to rules that 

were added by the final rule entitled 

‘‘Airplane Performance and Handling 

Qualities in Icing Conditions (72 FR 

44656, August 8, 2007) (Amendment 

25–121).4 Amendment 25–121 added 

specific requirements for airplane 

performance and handling qualities for 

flight in icing conditions. Sections 

25.143(j) and 25.207(h), at Amendment 

25–121, define requirements that apply 

if activating the IPS depends on the 

pilot seeing a specified ice accretion on 

a reference surface (not just the first sign 

of ice accretion). 

Section 25.1419(e) of this final rule 

requires one of three methods of 

detecting icing and activating the 

airframe IPS.5 Activation based on the 

pilot seeing a specified ice accretion on 

a reference surface (not just the first sign 

of ice accretion) is not one of the three 

methods allowed under this rulemaking, 

so any requirements associated with this 

method are no longer relevant. 

Therefore, minor conforming changes 

have been made to §§ 25.143(j) and 

25.207(h) to remove the references to, 

and requirements associated with, 

activating the IPS in response to the 

pilot seeing a specified ice accretion on 

a reference surface. Additional minor 

changes have been made to § 25.207(h) 

to improve readability, including 

moving a portion of existing 

§ 25.207(h)(2)(ii) to a new § 25.207(i). 

The text of part 25, appendix C, part 

II(e) has been revised to include a 

reference to the new § 25.207(i). 

In addition, minor changes have been 

made to § 25.207(b) to improve clarity 

and to correct an error introduced by 

Amendment 25–121. Section 25.207(b), 

as amended by Amendment 25–121, 

states, ‘‘Except for the stall warning 

prescribed in paragraph (h)(2)(ii) of this 

section, the stall warning for flight in 

icing conditions prescribed in paragraph 

(e) of this section must be provided by 

the same means as the stall warning for 

flight in non-icing conditions.’’ 

However, the stall warning prescribed 

by § 25.207(h)(2)(ii) is an exception only 

to the § 25.207(b) requirement that stall 

warning in icing conditions be provided 

by the same means as for non-icing 

conditions. It is not an exception to, nor 

is it associated with, the stall warning 

margin prescribed by § 25.207(e). The 

reference to § 25.207(e) is incorrect and 

potentially confusing. Therefore, it is 

removed by this final rule. 

Because of the reformatting of 

§ 25.207(h), as discussed above, the 

previous § 25.207(h)(2)(ii) is now 

§ 25.207(h)(3)(ii). The reference to this 

paragraph in § 25.207(b) is changed 

accordingly. Other minor wording 

changes have been made to improve 

clarity. We consider all of these changes 

to § 25.207(b) to be technical 

clarifications that do not change the 

intent of this paragraph or impose an 

additional burden on applicants. 

Below is a more detailed discussion of 

the rule as it relates to the comments we 

received on the NPRM. Appendix 1 

defines terms used in this preamble. 

II. Summary of Comments 

The FAA received 14 comments 

concerning the following general areas 

of the proposal: 

• Acceptable methods to determine if 

the airframe IPS must be activated. 

• Automatic cycling of the airframe 

IPS. 

Four of the commenters, the Airline 

Pilots Association (ALPA), National 

Transportation Safety Board (NTSB), 

BAE Systems Regional Aircraft, and The 

Boeing Company (Boeing), expressed 

support for the rule. ALPA supported 

the rule without recommendations to 

revise the rule. Twelve commenters 

suggested specific improvements or 

clarifications. They were the NTSB, 

BAE Systems Regional Aircraft, Boeing, 

the Air Crash Victims Families Group, 

Bombardier Aerospace, Marinvent 

Corporation, the Regional Airline 

Association, Swan International 

Sensors, Transport Canada, and three 

individuals. Ameriflight LLC 

(Ameriflight) opposed certain 

provisions of the rule. Summaries of the 

comments and our responses (including 

explanations of any changes to the final 

rule in response to the comments) are 

provided below.6

A. Ice Detection, Activation of Airframe 

IPS, and Automatic Cycling of Airframe 

IPS 

In the NPRM, we proposed one of the 

following three methods for ice 

detection and activation of the airframe 

IPS to ensure timely activation of the 

airframe IPS (proposed § 25.1419(e)): 

• A primary ice detection system that 

automatically activates or alerts the 

flightcrew to activate the airframe IPS; 

• Visual cues for recognition of the 

first sign of ice accretion combined with 

an advisory ice detection system that 

alerts the flightcrew to activate the 

airframe IPS; or 

• Identification of conditions 

conducive to airframe icing for use by 

the flightcrew to activate the airframe 

IPS when those conditions exist. 

In addition, proposed § 25.1419(g) 

would require an airframe IPS that 

operates cyclically (for example, deicing 

boots) to automatically cycle after the 

initial activation, or installation of an 

ice detection system to alert the 

flightcrew each time the deicing boots 

must be activated. 

The following comments were 

received on these proposals. 

1. Oppose Installation of an Ice 

Detection System 

Ameriflight opposed the installation 

of an ice detection system because 

properly trained flightcrews can easily 

detect ice accretion by means such as 

ice forming in the corners of the 


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7The commenter noted that this is particularly 

true of older boots that have been on the wing for 

several seasons and which—although completely 

airworthy—have leading edges which have become 

somewhat roughened by the impacts of ice crystals, 

snow, hail, etc., and provide a better ‘‘tooth’’ to 

which structural ice can adhere. 

windshield or on windshield wiper 

arms. An individual commenter 

believed nothing, including an ice 

detector, can replace pilots looking out 

the window to gather information on 

icing. 

Ameriflight also suggested that it 

would be difficult or impossible to 

design a sufficiently reliable ice 

detection system that would be 

economically feasible and a practicable 

substitute for flightcrew training and 

vigilance. The individual commenter 

opposed installation of an ice detection 

system because of his experience on a 

military airplane that was equipped 

with an unreliable icing warning light. 

The FAA agrees that flightcrew 

training and vigilance are extremely 

important to ensure the safe operation of 

aircraft in icing conditions. However, 

visual observation of ice accretion 

alone, as suggested by Ameriflight and 

the individual commenter, is not 

sufficient to ensure timely operation of 

the airframe IPS. The flightcrew’s 

observation of ice accretions can be 

difficult during times of high workload, 

nighttime operations, or when clear ice 

has accumulated. In addition, there 

have been icing accidents and incidents 

where the flightcrew was either 

completely unaware of ice accretion on 

the airframe, or was aware of ice 

accretion but judged that it was not 

significant enough to warrant operation 

of the airframe IPS. Therefore, reliance 

on only flightcrew visual observation of 

ice accretion alone is not adequate and 

must be supplemented with an advisory 

ice detection system to provide an 

acceptable level of safety. 

The FAA acknowledges that it is not 

a simple task to design and certificate an 

ice detection system. However, ice 

detection systems exist today that meet 

the reliability requirements of part 25. 

Section 25.1309 ensures the degree of 

reliability of an airframe IPS is 

commensurate with the hazard level 

associated with the failure of the 

airframe IPS. 

In response to the contention that an 

ice detector would not be economically 

feasible, the FAA notes that on recent 

part 25 airplane certifications 

manufacturers sought and received 

approval for installation of ice detectors 

without an FAA requirement for such a 

system. Therefore, the FAA infers that 

these manufacturers consider the 

installation of ice detectors 

economically feasible. 

2. Reliability of Advisory Ice Detection 

System 

Transport Canada suggested that the 

reliability level of the advisory ice 

detection system should be on the order 

of 1 × 10 5 failure per flight hour. 

Transport Canada indicated the 

classification assigned to the 

unannunciated loss of an advisory ice 

detection system would appear to 

depend upon the advisory ice detection 

system design, the IPS design, and the 

airplane on which it is installed. 

Therefore, it is Transport Canada’s 

position that specific cases may need to 

consider the unannunciated loss of the 

advisory ice detection system as a major 

failure. The natural tendency of 

flightcrews to become accustomed to 

using the advisory ice detection system 

may increase the need to make 

flightcrews aware of failure of the 

advisory ice detection system. The 

flightcrews may need to take extra 

precautions when they have detected a 

possible failure of the advisory ice 

detection system. 

The FAA infers that Transport Canada 

would like the proposed rule changed to 

include a minimum reliability 

requirement for the advisory ice 

detection system. The FAA finds it is 

unnecessary to revise this rule to 

include a minimum reliability 

requirement for the advisory ice 

detection system because § 25.1309 

requires the determination of the hazard 

level associated with failure of any 

airplane system which then drives the 

required degree of reliability of that 

system. Additionally it would not be 

appropriate to pick a specific minimum 

reliability requirement for the advisory 

ice detection system because, as pointed 

out by the commenter, the hazard level 

associated with the unannunciated loss 

of the advisory ice detection system may 

depend upon the advisory ice detection 

system design, the airframe IPS design, 

and the airplane on which it is installed. 

However, the FAA may consider 

including guidance on advisory ice 

detection system reliability in the 

associated advisory circular. 

3. Do Not Activate Pneumatic Deicing 

Boots at First Sign of Ice Accretion 

Ameriflight did not support activation 

of pneumatic deicing boots at the first 

sign of ice accretion, noting that these 

boots work better and continue to shed 

ice more effectively for a longer period 

if airfoil leading-edge ice is allowed to 

build to a sufficient thickness before 

cycling the boots. The commenter stated 

that when the boots are operated at the 

first indication of ice, the ice is only 

partially shed. The ice remaining on the 

boot provides a rough surface on which 

additional ice accumulates more readily 

than on a smooth boot surface, 

shortening the duration of the boots’ 

ability to clean the wing effectively.7

Thus, the commenter believed that 

activating the boots at the first sign of 

ice was actually contrary to safety and 

Ameriflight’s long experience with this 

system. 

The FAA has issued airworthiness 

directives requiring activation of 

pneumatic deicing boots early and 

often. The airworthiness directives and 

this rule address icing accidents and 

incidents where the flightcrew was 

either completely unaware of ice 

accretion on the airframe, or was aware 

of ice accretion but judged that it was 

not significant enough to warrant 

operation of the airframe IPS. 

The commenter raised concerns over 

residual ice, which is ice remaining (not 

shed) after a complete boot cycle. The 

FAA participated in high and low speed 

icing wind tunnel tests that contradict 

the commenter’s position that boots 

work better, and continue to shed ice 

effectively, for a longer period if airfoil 

leading ice is allowed to build before 

cycling the boots. 

The higher speed icing wind tunnel 

tests (≥180 KCAS) showed that ice was 

shed after each boot activation and that 

after 2 or 3 cycles there was no 

discernible difference between ice 

accretions from early versus delayed 

activation of the boots. The residual ice 

that remained on the boot after cycling 

at the first sign of ice accretion was 

always smaller than the amount of ice 

that was present on the boot during the 

time that it took for 1⁄4-inch of ice to 

form. 

The lower speed icing wind tunnel 

tests (≤144 KCAS) showed large 

amounts of residual ice which the boots 

had difficulty shedding, regardless of 

the activation method employed. 

Immediate activation of an automatic 

system did not degrade ice shedding 

performance. Cycling early and often 

resulted in shedding sooner than 

waiting for a specified ice accretion 

thickness. For example, simulating an 

automatic one minute system activated 

at first sign of icing at 14 °F, 108 KCAS, 

resulted in a ‘‘good shed’’ at the 15th 

cycle at 15 minutes. Waiting for a 1⁄4

inch accretion before cycling resulted in 

a ‘‘good shed’’ at the 12th cycle at 20 

minutes. The residual ice after ‘‘good 

sheds’’ was similar regardless of the 

boot activation method. Based on the 

results of these tests, we do not agree 

with Ameriflight’s position about the 


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effectiveness of pneumatic deicing 

boots. 

4. Oppose Automatic Activation and 

Cycling of Airframe IPS 

Ameriflight also opposed any system 

that would automatically activate ice 

protection equipment or automatically 

cycle pneumatic deicing boots. 

Ameriflight suggested automatic 

activation of deicing boots during low 

speed operation, takeoff, or in the 

landing flare could cause handling 

quality problems on some aircraft. The 

commenter stated that although such 

automatic operation could be inhibited 

by airspeed, landing gear position, or 

other sensors, these in turn add 

increments of complexity and potential 

unreliability that tend to offset the 

automatic systems’ safety value. 

The FAA agrees that automatic 

activation of the deicing boots during 

some phases of flight (for example, 

landing flare) could result in handling 

quality problems on some airplanes. As 

Ameriflight pointed out, inhibiting 

automatic activation during these 

phases of flight to prevent any handling 

quality problems adds complexity to the 

system and could potentially increase 

the chances for the system not to 

activate when it is needed. However, the 

FAA finds that the increase in safety 

afforded by automatic activation of the 

airframe IPS outweighs the concerns 

expressed by Ameriflight and that 

compliance with other regulations 

would mitigate those concerns. 

Section 25.143(a) requires airplanes to 

be safely controllable and maneuverable 

during takeoff, climb, level flight, 

descent, and landing. Section 25.143(b) 

states that it must be possible to make 

a smooth transition from one flight 

condition to another without 

exceptional piloting skill, alertness, or 

strength under any probable operating 

condition. If the airplane cannot operate 

safely with the airframe IPS activated 

during a particular phase of flight, 

automatic activation of the airframe IPS 

would need to be inhibited during that 

phase of flight. 

Any potential effect on the reliability 

of the system to activate would be 

assessed in accordance with § 25.1309, 

which requires that systems must be 

designed to perform their intended 

function under any foreseeable 

operating condition. Section 25.1309 

also establishes the minimum allowable 

system reliability, which is based on the 

hazard that would result from failure of 

the system. Therefore, the increase in 

safety afforded by automatic activation 

of the airframe IPS would not be offset 

by the increase in complexity and 

potential effect on reliability if 

automatic activation must be inhibited 

in certain flight phases. 

Ameriflight commented that IPS other 

than deicing boots should be controlled 

by active involvement of the flightcrew, 

rather than automatically. IPS operation 

at inopportune times could actually 

decrease safety, for example by causing 

(i) preexisting ice accumulations to be 

shed into engine inlets, (ii) undesired 

drawdown of engine bleed air, or (iii) an 

excess electrical load. Systems could be 

designed with sensors to protect against 

such inopportune operation, but only at 

the price of additional complexity and 

unreliability. Ameriflight opposed any 

system that would automatically 

activate ice protection equipment or 

automatically recycle pneumatic deicing 

boots because automatic systems may 

fail, and the flightcrew might be 

unaware the IPS is not operating. 

‘‘Automatic’’ systems add complexity, 

testing requirements, and systems 

interfaces, and often result in decreased 

overall reliability and tend to remove 

the flightcrew from the operational loop. 

The final rule does not require 

automatic activation of airframe IPS, but 

does allow it if a primary ice detection 

system is installed. If an applicant 

chooses to certificate a system to 

activate the airframe IPS automatically, 

compliance with part 25 regulations 

ensure the airplane can operate safely 

any time the airframe IPS is operated. 

Issues raised by the commenter such as 

ice shedding, bleed air, and electrical 

power are considered during airplane 

certification. As previously mentioned, 

any system that would be necessary to 

inhibit automatic activation would be 

required to comply with § 25.1309, 

which ensures system reliability 

commensurate with the hazard 

associated with the failure of that 

system. As indicated by the commenter, 

an automatic system may fail. However, 

§ 25.1309 requires assessing the hazard 

associated with the failure and 

providing appropriate warnings 

commensurate with the hazard. 

Compliance with part 25 ensures the 

safe operation of the airplane if the 

airframe IPS is automatically activated 

regardless of whether the airframe IPS is 

a thermal anti-ice system or a deicing 

boot system. 

5. Necessity for Visual Cues in 

Combination With an Advisory Ice 

Detector 

Bombardier noted the requirement for 

an advisory system, in combination 

with visual cues for recognition of ice 

accretion, implies that visual cues are 

necessary because of ice detector failure 

and not ice detector performance. The 

fact that no visual cues are necessary for 

a primary ice detection system (dual ice 

detectors) seems to indicate an intent to 

focus on ice detection failure. Therefore, 

the commenter believed that it would be 

appropriate to address how primary ice 

detectors should be certified knowing 

these potential limitations. 

The FAA reviewed our airworthiness 

directives that require operating deicing 

boots at the first sign of ice accretion. 

We determined that this means of IPS 

operation should be improved because 

such observations can be difficult 

during times of high workload, 

nighttime operations, or when clear ice 

has accumulated. Therefore, to mitigate 

the effects of human sensory limitations 

and inadequate attention due to 

workload, the final rule requires visual 

cues of ice accretions in combination 

with an advisory ice detector. The 

combination of visual cues and advisory 

ice detectors is intended to address the 

potential limitations of human beings, 

not of the ice detectors, as suggested by 

the commenter. Limitations of primary 

ice detectors, as well as advisory ice 

detectors, are addressed during 

certification through the requirements of 

§§ 25.1301 and 25.1309. These 

regulations require that equipment 

function properly when installed, 

perform its intended functions under 

any foreseeable operation condition, 

and ensure system reliability 

commensurate with the hazard 

associated with a failure of that system. 

6. Require Automatic Activation of 

Airframe IPS 

An individual commenter requested 

that § 25.1419(e) be revised to allow 

only automatic activation of airframe 

IPS in appendix C icing conditions, and 

to require IPS status displays. The 

commenter suggested that all other 

proposed options to ensure timely 

activation of the airframe IPS be deleted. 

The commenter believed that visual 

cues are not adequate, there is no 

correlation between the ice formed on 

the airframe and the thickness of the ice 

formed on the ice detector, and 

automatic activation would minimize 

hazards by making flightcrews aware of 

icing conditions early. 

The FAA disagrees and maintains that 

the proposed standard that allows 

several means to ensure timely 

activation of the airframe ice protection 

equipment is acceptable. Icing accidents 

and incidents do not support the 

suggested revision. The FAA 

acknowledges that automatic activation 

of airframe IPS based on icing 

conditions will likely result in earlier 

activation and minimize the effects of 

icing compared to waiting until ice 

accretions have formed on the airframe. 


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8The commenter noted that the Cessna Citation 

560 was equipped with deice boots that do not 

cycle automatically, which require pilots to 

continually monitor accumulation and reactivate 

the deice boots each time. 

However, later activation is acceptable, 

provided an applicant substantiates the 

airplane can operate safely with the ice 

accretion present at the time the 

airframe IPS is activated and becomes 

effective. Consequently, if the airframe 

IPS is activated based on an ice detector, 

it is the ice accretion present on the 

airframe that is important, not the 

correlation between the ice shape on the 

ice detector and the airframe. The 

commenter pointed out icing accidents 

and incidents where the flightcrew was 

unaware of ice accretions and 

concluded that visual cues are 

inadequate. The FAA concurs that 

visual cues alone are not adequate, but 

visual cues in addition to an advisory 

ice detection system would provide an 

acceptable level of safety and mitigate 

the effects of human sensory limitations 

and inadequate attention due to 

workload. 

7. Remove Option To Activate Airframe 

IPS Based on Temperature and Visible 

Moisture 

Proposed § 25.1419(e)(3) would allow 

activation of the airframe IPS based on 

conditions conducive to airframe icing 

as defined by appropriate static or total 

air temperature and visible moisture. 

Three commenters, Transport Canada, 

Swan International Sensors, and an 

individual commenter did not consider 

proposed § 25.1419(e)(3) an acceptable 

alternative to requiring an ice detection 

system. Transport Canada noted that it 

is common to base temperature 

indication on a single sensor, which 

may not have the required reliability 

and failure monitoring. Moreover, the 

display of temperature may not be 

conspicuous particularly on electronic 

flight instrument systems. In addition, it 

may not be easy to see visible moisture 

at night. The commenter requested that 

if paragraph (e)(3) is retained, it should 

be limited to airplanes that are at a 

lower risk of icing related incidents and 

accidents. The individual commenter 

stated that training flightcrews to 

recognize conditions conducive to icing 

is not an adequate solution because 

such training and documentation have 

existed for some time, yet icing related 

accidents still occurred. 

The FAA concludes that 

§ 25.1419(e)(3) should be retained as 

proposed because activation of the 

airframe IPS using visible moisture and 

temperature is based on the 

methodology currently being used safely 

for activating engine IPS. Flightcrews 

are trained to recognize conditions 

conducive to icing (that is, visible 

moisture and temperature) and have 

used this method safely for the 

operation of engine IPS. While there 

may be some challenges to observing 

visible moisture at night, the challenge 

is no different than for engine IPS 

activation. The FAA expects that 

activation of the airframe IPS using the 

same type of cues will result in timely 

activation just as it has for engines. 

Furthermore, the accident and 

incident history does not support the 

commenter’s position that training 

flightcrews to recognize conditions 

conducive to icing has not been 

successful. For airplanes with an 

airframe IPS that is activated based on 

visible moisture and temperature, the 

FAA is unaware of accidents or 

incidents attributed to the flightcrew not 

activating the airframe IPS. 

Regarding the concern over the 

reliability of the current equipment used 

to detect temperature, the equipment 

must meet the requirements of 

§ 25.1309. This could result in the need 

to install different temperature sensing 

equipment than what is used on aircraft 

today. 

8. Allow Temperature and Visible 

Moisture in Combination With an 

Advisory Ice Detection System 

Transport Canada recommended the 

FAA include temperature and visible 

moisture in combination with an 

advisory ice detection system as an 

acceptable configuration under the 

proposed rule. 

The FAA determines there is no need 

to revise the rule to explicitly provide 

the suggested option. The regulations 

provide minimum requirements and an 

applicant has the option of exceeding 

these requirements. Therefore, even 

though the suggested option is not 

identified in the proposed rule, it would 

be acceptable for an applicant to comply 

with proposed § 25.1419(e)(3) and 

voluntarily go beyond that requirement 

and install an advisory ice detection 

system. 

9. Need Definition of Environmental 

Conditions Conducive to Icing 

The National Transportation Safety 

Board (NTSB) commented that industry 

could not realistically be expected to 

implement § 25.1419(e)(3) until the FAA 

provides a more specific definition of 

‘‘environmental conditions conducive to 

icing.’’ Swan International Sensors 

stated that the flightcrew would be 

required to interpret icing conditions 

because they are not defined adequately 

by paragraph (e)(3). 

The FAA concludes that the proposed 

rule adequately defined environmental 

conditions conducive to icing and does 

not require interpretation by the 

flightcrew. The rule requires the 

manufacturer to identify conditions 

conducive to airframe icing as defined 

by an appropriate static or total air 

temperature and visible moisture for use 

by the flightcrew to activate the airframe 

IPS. The proposed rule defined the 

environmental conditions as a static or 

total air temperature and visible 

moisture. Advisory circular (AC) 25– 

1419–2, Compliance with the Ice 

Protection Requirements of 

§§ 25.1419(e), (f), (g), will provide 

guidance on determining the 

temperature cue. Therefore, we made no 

changes to proposed § 25.1419(e)(3) in 

this final rule. 

10. Require Aircraft Be Equipped With 

All Three Proposed Methods of 

Airframe Ice Detection 

The proposed § 25.1419(e) would 

require one of three ice detection and 

activation methods. The Air Crash 

Victims Families Group and an 

individual commenter requested that 

the final rule require all three ice 

detection and activation methods 

identified in proposed § 25.1419(e). The 

commenters also requested that the FAA 

require automatic ice detection systems 

to warn pilots of icing and to activate 

IPS automatically. The commenters 

referenced the Circuit City airplane 

accident in Pueblo, Colorado, on 

February 16, 2005, where the NTSB 

found the probable cause to be the 

flightcrew’s failure to monitor and 

maintain airspeed and comply with 

procedures for ice boot activation on 

approach.8 In addition, the NTSB found 

that distractions impeded the 

flightcrew’s ability to monitor and 

maintain airspeed and manage the 

deicing system. 

The FAA finds that icing accidents 

and incidents do not support the 

commenters’ suggestion to require all 

three proposed methods to ensure 

timely activation of the airframe IPS or 

require a system to activate the airframe 

IPS automatically. The three proposed 

methods would independently ensure 

timely activation of the airframe IPS. 

The FAA is unaware of any icing 

accidents or incidents attributed to 

untimely activation of the airframe IPS 

on an airplane that had equipment 

compliant with this rule. The flightcrew 

of the Circuit City airplane relied on 

visual observation of ice accretions for 

determining if the airframe IPS should 

be activated and cycled manually. There 

was not a detector to tell the flightcrew 

to cycle the airframe IPS. This rule 

requires an advisory ice detection 


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9Aerodynamic performance monitoring systems 

directly measure the degradation of airfoil 

performance caused by the roughness and profile 

changes induced by the contamination of the airfoil. 

system in addition to visual observation 

of the first sign of ice accretion as a 

means to determine the airframe IPS 

must be activated. In addition, the rule 

addresses flightcrew workload by 

requiring deice boots to automatically 

cycle or by equipping the airplane with 

an ice detection system to alert the 

flightcrew each time the airframe IPS 

must be cycled. For these reasons, the 

suggested revisions are not being 

adopted. 

11. Require Manual Back-Up to 

Automatic Activation of Airframe IPS 

Proposed § 25.1419(g) addressed the 

flightcrew workload associated with an 

airframe IPS that operates cyclically and 

that requires continuous monitoring of 

ice accretions to determine when to 

activate the IPS. Proposed paragraph 

(g)(2) requires that these systems 

automatically cycle the airframe IPS to 

eliminate the need to continuously 

monitor ice accretions. An individual 

commenter requested that proposed 

paragraph (g) be revised to require 

manual system activation as a back-up 

to automatic activation. Compliance 

with § 25.1309, which requires an 

assessment of the hazard associated 

with the failure of a system, will 

determine whether a manual system is 

required as a back-up to an automatic 

activation system. Therefore, the FAA 

finds it is unnecessary to require a backup manual system as suggested by the 

commenter. 

12. Allow an Aerodynamic Performance 

Monitoring System 

Marinvent and the Regional Airline 

Association requested revising the 

proposed rule to include an 

aerodynamic performance monitoring 

(APM) system as an alternative to ice 

detection systems.9 The commenters 

believed APMs have several advantages 

over ice detectors, but that they do not 

inherently detect ice. Therefore, the 

proposed rule text did not directly 

address APMs because they are not 

strictly ‘‘ice detection systems.’’ The 

commenters understood that applicants 

may propose the APM as an alternative 

means of compliance by demonstrating 

an equivalent level of safety. However, 

the commenters thought the process of 

obtaining an equivalent level of safety 

finding would discourage the use of this 

alternative and believed there was a 

fundamental conceptual difference 

between the ice detection and 

aerodynamic monitoring, making it 

difficult for the applicant and the 

regulator to establish common ground to 

demonstrate an equivalent level of 

safety. The commenters contended the 

existing proposed rule text would 

effectively exclude the APM systems as 

a viable alternative means of 

compliance with the regulation. 

The Regional Airline Association 

added that at least one of their associate 

members currently provides an APM 

system as an option in their aircraft 

(Aerospatiale model ATR 72) for their 

airline members. 

The FAA concludes that, at this time, 

APMs are not sufficiently mature to use 

as a method to ensure timely activation 

of the airframe IPS. Further, contrary to 

the commenters’ beliefs, the equivalent 

level of safety process is commonly 

used in certification programs and 

would not discourage the use of 

alternatives such as an APM. 

In response to the Regional Airline 

Association’s comment that an APM is 

currently offered as an option on the 

Aerospatiale ATR 72 aircraft, the FAA is 

aware that Aerospatiale has certificated 

an aircraft performance monitor, not an 

aerodynamic performance monitor. The 

aircraft performance monitor system 

used on the ATR 72 is intended to 

provide the flightcrew with information 

that could help them manage a severe 

icing encounter. The ATR 72’s aircraft 

performance monitor system is not 

intended, nor certificated, to provide the 

flightcrew with information to ensure 

the airframe IPS is activated in a timely 

manner. 

B. Airframe Ice Protection System 

Operation 

Proposed § 25.1419(f) would allow an 

applicant to substantiate that the 

airframe IPS need not be operated 

during specific phases of flight. An 

individual commenter requested that 

§ 25.1419(f) be revised to allow airplane 

operations with the IPS inactive if the 

airplane can be operated safely with the 

ice accretions associated with probable 

failures. The commenter also requested 

that § 25.1419(f) be revised to require 

that safe operation be demonstrated by 

flight test, icing tunnel tests, or other 

means. 

The FAA finds the suggestion to 

consider only the ice accretions 

associated with probable failures 

unacceptable. Compliance with 

§ 25.1309 determines the failures that 

must be considered, and this rule 

should not predetermine that only 

probable failures need be considered. 

Regarding the suggestion to specify the 

acceptable means of showing 

compliance, the FAA finds it is not 

necessary because § 25.1419(a) and (b) 

already specify the means that can be 

used to substantiate that an airplane can 

operate safely in icing conditions. For 

these reasons, the FAA did not adopt 

the suggested changes to § 25.1419(f). 

C. Airplane Flight Manual Requirements 

Proposed section § 25.1419(h) would 

require that procedures for operation of 

the IPS be established and documented 

in the Airplane Flight Manual (AFM). 

BAE Systems Regional Aircraft 

requested the word ‘‘airframe’’ be added 

to § 25.1419(h). The FAA finds that 

adding the word ‘‘airframe’’ to 

§ 25.1419(h) is not necessary because 

the procedures for operation of both 

engine and airframe IPS must be in the 

AFM. Traditionally, manufacturers 

provide adequate information in the 

AFM regarding the operation of the 

engine IPS, but information for an 

airframe IPS is sometimes lacking or is 

not consistent with the methods of 

operation used during certification. 

Proposed paragraph (h) is included to 

ensure future AFMs also include 

information for the operation of airframe 

IPS. 

Another commenter requested that 

§ 25.1419(h) be deleted because the 

requirement is already covered by the 

existing regulation in the section titled 

‘‘Airplane Flight Manual.’’ 

The FAA finds that the sections 

relating to the AFM in part 25, Subpart 

G (§§ 25.1581–25.1587) do not explicitly 

address IPS operations. Therefore, the 

Subpart G regulations must be 

supplemented with the proposed 

§ 25.1419(h) to ensure that procedures 

for operating the IPS are included in the 

AFM and are consistent with the 

requirements of § 25.1419. For these 

reasons, the suggested revision is not 

being adopted in this final rule. 

Boeing requested that proposed 

§ 25.1419(g)(1) be changed to require 

that the IPS must operate continuously 

only while the aircraft remains in icing 

conditions. The proposed rule would 

require operating the anti-icing system 

continuously throughout a potentially 

long flight after exiting icing conditions. 

Such continued operation while not in 

icing conditions is not necessary and 

wastes fuel. Boeing suggested that the 

proposed rule be revised to specify 

when an IPS that operated continuously 

can be deactivated. 

Based on Boeing’s comment, it 

appears the intent of § 25.1419(g) may 

be unclear. Proposed § 25.1419(g) 

provided three options to minimize the 

flightcrew workload associated with 

airframe IPS operation. One option 

(§ 25.1419(g)(1)) is an airframe IPS that 

operates continuously. Section 

25.1419(g)(1) has been revised to clarify 


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10The commenter estimated the non-recurring 

costs could be: Architecture/integration $7,500, 

qualification testing $10,000, system certification 

$50,000, and installation design $5,000. 

that the airframe IPS must be designed 

to operate continuously, not to require 

continuous operation of an airframe IPS. 

We also clarified that procedures for 

operation of the IPS as specified in 

§ 25.1419(h) include both activation and 

deactivation procedures. In addition, we 

revised § 25.1419(g)(1) to say that the 

IPS must be designed to operate 

continuously. 

For future certification programs (as 

with past certification programs), it is 

incumbent upon the manufacturer to 

propose and substantiate when it is 

acceptable to deactivate the IPS. The 

only difference from past certifications 

will be that the activation requirements 

of § 25.1419(e) must be considered. 

D. Other Comments 

1. Clarify the Rule Is Applicable to 

Airframe IPS 

BAE Systems Regional Aircraft 

requested that § 25.1419(f) and (g) be 

modified to indicate the ‘‘airframe’’ IPS 

are being referenced. 

The FAA agrees that §§ 25.1419(f) and 

(g) should be clarified by adding the 

word ‘‘airframe.’’ Therefore, in 

§ 25.1419(f), we revised the introductory 

language to reference the airframe IPS 

(‘‘Unless the applicant shows that the 

airframe ice protection system * * *). 

In § 25.1419(g), we made a similar 

revision to the introductory language 

(‘‘After the initial activation of the 

airframe ice protection system * * *). 

2. Expand Rule To Include Certain 

Existing Airplanes and Prohibitions 

With IPS Inoperable 

The NTSB requested a revision to 

address its perceived ongoing 

disconnect between the industry’s 

guidance on deicing boot activation and 

what the FAA has learned and research 

has shown regarding ice bridging and 

deice boot effectiveness. The NTSB 

noted the Cessna 208 Caravan AFM 

instructs crews to wait for 1⁄4 to 3⁄4 inch 

of ice to accrete before activating the 

pneumatic deicing boots. 

The FAA finds that for the new part 

25 airplane and for existing part 25 

airplanes that are modified in the future 

with significant airframe IPS design 

changes, this rule precludes the 

potential for perpetuating the belief that 

flightcrews should wait for a specific 

amount of ice to accumulate before 

activating the deicing boots. The final 

rule requires activation of the airframe 

IPS based on ice detectors or icing 

conditions and requires procedures for 

operating the IPS in the AFM. 

Therefore, for new part 25 airplanes, the 

industry guidance in the AFM will 

reflect the FAA regulatory requirements 

for activation of the IPS which does not 

allow activation of deicing boots based 

on the flightcrew determining that a 

specified thickness of ice has 

accumulated. 

The NTSB, Air Crash Victims 

Families Group, and one other 

commenter requested the proposed rule 

be expanded to include existing 

airplanes equipped with pneumatic 

deicing boots and reference the NTSB 

safety recommendations A–98–91, A– 

98–100, A–07–14, and A–07–16 (which 

recommend icing related actions the 

FAA should take for existing airplanes). 

We disagree. The NPRM did not 

address this issue, and revising this 

final rule to include retrofit 

requirements for existing airplanes 

would delay its issuance, which is not 

in the interest of safety. However, the 

FAA may consider additional 

rulemaking to address activation of the 

IPS on part 121 airplanes at a later date. 

The NTSB also believed the proposed 

rule should prohibit crews from 

operating the airplane when certain 

functions of the IPS are inoperable, and 

should prohibit flight into known icing 

conditions if certain functions of the IPS 

are inoperable. 

The FAA maintains that if certain 

equipment is inoperable, transport 

category airplanes should be prohibited 

from flight in forecasted icing 

conditions in addition to prohibiting 

flight in known icing conditions (as 

suggested by the NTSB). However, we 

do not concur with incorporating such 

a requirement into a certification rule. 

The FAA utilizes the Master Minimum 

Equipment List (MMEL) to evaluate 

whether an airplane may be operated 

with a particular piece of equipment 

inoperative. Each airplane is unique and 

the MMEL is the best way to determine 

the impact of an inoperable piece of 

equipment. 

3. Revise Rule To Encourage Specific 

Airfoil Designs 

The Regional Airline Association 

noted that several aircraft types over 

many years have been operated safely 

without any incidents or accidents 

attributed to icing. The commenter 

requested the proposed rule be rewritten 

to encourage airfoil design as the best 

means to address safety concerns due to 

operations in icing conditions. 

Although the FAA does not write 

regulations to ‘‘encourage’’ specific 

airfoil designs, we do establish the 

performance and handling requirements 

an airplane must meet to substantiate 

that the airplane can operate safely in 

icing conditions. These safety 

requirements (to a certain extent) drive 

the design of the airfoil. However, it is 

the responsibility of the airframe 

manufacturer to design an airplane that 

meets the Federal Aviation Regulations 

icing regulations. 

E. Economic Analysis 

An individual commenter stated that 

the Goodrich Corporation cost estimates 

identified in the NPRM appear to be 

realistic, but the non-recurring costs 

could be reduced by a system that uses 

a detector that is different than the 

assumed ice detector. The commenter 

suggested using a ‘‘universal’’ sensor or 

detector that is independent of the 

airplane type and installation location; 

like a pressure sensor, a temperature 

sensor, a humidity sensor, or a system 

that consists of sensors that are 

universal.10

The commenter provided cost 

estimates that are less than the ice 

detector certification estimates used in 

our economic assessment. However, 

even with the more costly estimates, the 

FAA concluded the economic impact of 

the rulemaking is minimal. Since 

decreasing the cost estimates would not 

affect this conclusion, the FAA has 

determined it is not necessary to revise 

the costs in our economic assessment. 

The FAA requested comments from 

U.S. manufacturers on their plans to 

produce a new part 25 certificated 

aircraft with deicing systems that 

operate cyclically and the associated 

certification costs. Bombardier and 

Transport Canada referenced this FAA 

request, but did not provide any data. 

Bombardier believes the FAA’s 

economic analysis, which noted the 

trend of part 25 manufacturers to install 

thermal anti-ice protection systems in 

newly certificated part 25 airplanes, 

implied that the FAA considered 

‘‘cyclical’’ deicing systems to be 

anachronistic. Bombardier indicated 

that technology in development may 

reintroduce cyclical deicing systems. 

Transport Canada indicated that if 

cyclical deicing systems are being 

considered for the future, then the FAA 

trend noted in the NPRM would not be 

correct. 

While technology development may 

result in the reintroduction of cyclical 

deicing systems in the future, the FAA 

is unaware of any actual plans to 

produce a new part 25 certificated 

aircraft with deicing systems that 

operate cyclically and the associated 

certification costs. Without such 

information, we believe the economic 

assessment stating that the trend for 


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new part 25 aircraft certifications is 

toward thermal anti-ice ice protection 

systems is accurate. 

Paperwork Reduction Act 

The Paperwork Reduction Act of 1995 

(44 U.S.C. 3507(d)) requires that the 

FAA consider the impact of paperwork 

and other information collection 

burdens imposed on the public. We 

have determined that there is no current 

or new requirement for information 

collection associated with this 

amendment. 

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. 

III. Regulatory Evaluation, Regulatory 

Flexibility Determination, International 

Trade Impact Assessment, and 

Unfunded Mandates Assessment 

Changes to Federal regulations must 

undergo several economic analyses. 

First, Executive Order 12866 directs that 

each Federal agency shall propose or 

adopt a regulation only upon a reasoned 

determination that the benefits of the 

intended regulation justify its costs. 

Second, the Regulatory Flexibility Act 

of 1980 (Pub. L. 96–354) requires 

agencies to analyze the economic 

impact of regulatory changes on small 

entities. Third, the Trade Agreements 

Act (Pub. L. 96–39) prohibits agencies 

from setting standards that create 

unnecessary obstacles to the foreign 

commerce of the United States. In 

developing U.S. standards, this Trade 

Act requires agencies to consider 

international standards and, where 

appropriate, that they be the basis of 

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. 

An assessment has been conducted of 

the economic cost impact of the final 

rule amending § 25.1419 of Title 14 of 

the Code of Federal Regulations (14 

CFR) part 25, and we have determined 

the final rule has minimal costs. This 

final rule is the result of information 

gathered from a review of historical 

icing accidents and incidents. It is 

intended to improve the level of safety 

when part 25 airplanes are operated in 

icing conditions. 

Amendment 25–121 revised § 25.207 

to add requirements for considering the 

effects of icing on stall warning. At the 

time we issued Amendment 25–121, it 

was permissible for type certificate 

applicants to instruct pilots to wait for 

a specified amount of ice accretion to 

accumulate before activating the ice 

protection system (IPS). Section 

25.207(h)(1), as adopted in Amendment 

25–121, addressed this scenario by 

requiring flight testing with the 

specified amount of ice accretion to 

show the airplane could be operated 

safely until the IPS is functioning. This 

rule will prohibit use of this method for 

activating the IPS. Therefore, there is no 

longer any need to have the existing 

provision § 25.207(h)(1) that provides 

stall warning margin requirements for 

this method, and we are removing those 

provisions from § 25.207. This is a 

conforming change, and does not add 

any new requirements or costs. In 

addition, § 25.207 has been revised to 

improve its readability and to correct an 

error introduced by Amendment 25– 

121, but none of these revisions affect 

the substantive requirements. 

This final rule requires newly 

certificated part 25 transport category 

airplanes certificated for flight in icing 

conditions to have one of the following 

methods to detect ice and activate the 

airframe IPS: 

• A primary ice detection system, 

automatic or manual; 

• The definition of visual cues for 

recognition of ice accretion on a 

specified surface combined with an 

advisory ice detection system that alerts 

the flightcrew; or 

• The identification of icing 

conditions by an appropriate static or 

total air temperature and visible 

moisture cues. 

The FAA did not receive comments 

causing us to change our NPRM 

determination that the expected costs 

are minimal. Bombardier indicated 

future technology may reintroduce 

cyclical deicing systems. Since 1971, no 

U.S. manufacturer has certificated 

cyclical deicing systems. Also, recent 

part 23 Very Light Jet (VLJ) certification 

programs have automatic cyclical 

deicing systems. We do not anticipate 

manufacturers to certificate manuallycycled deicing systems. 

A. Cost Discussion 

1. Major Assumptions 

This evaluation makes the following 

assumptions: 

• We used a $50 hourly rate for a 

mechanic/technician and a $75 hourly 

rate for an engineer working for an 

airplane manufacturer or modifier. 

• Whenever various compliance 

options are available to the 

manufacturers, we chose the least costly 

option in our analysis. 

Other data and derived assumptions 

are discussed in the following sections 

on costs and benefits. 

2. Estimate of Costs 

This section discusses the costs of a 

new requirement for transport category 

airplane manufacturers to include a 

method of ice detection on newly 

certificated airplanes. The cost estimate 

included below is not an estimate per 

manufacturer, rather an estimate per 

new part 25 airplane certification. 

This final rule will require 

manufacturers of part 25 airplanes to 

provide the flightcrew with an effective 

method of ice detection. Such a method 

can provide a means, using an ice 

detection system (IDS), to alert the 

flightcrew of icing conditions and 

enable timely activation of the airframe 

IPS for the initial and any subsequent 

cycles. 

The requirements for ice detection 

and activation of the airframe IPS are 

applicable to all phases of flight, unless 

it can be shown that the airframe IPS 

need not be operated during specific 

phases of flight. If the airframe IPS 

operates in a cyclical manner, it must 

either include a system that 

automatically cycles the airframe IPS, or 

there must be a method that alerts the 

flightcrew each time the airframe ice 

protection system must be cycled. This 

final rule requires: 

• (e)(1) A primary IDS that 

automatically activates or alerts the 

flightcrew to activate the airframe IPS; 

• (e)(2) A definition of visual cues for 

recognition of the first sign of ice 

accretion on a specified surface 

combined with an advisory IDS that 

alerts the flightcrew to activate the 

airframe IPS; or 

• (e)(3) Identification of conditions 

conducive to airframe icing as defined 

by an appropriate static or total air 

temperature and visible moisture for use 

by the flightcrew to activate the airframe 

IPS. 

Any of the three ice detection 

methods will enable timely activation of 

the airframe IPS and satisfy the 

requirements of this final rule. 


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The first method of ice detection is 

the use of a primary IDS. A primary IDS 

usually has two ice detectors. The cost 

of an ice detector used in this analysis 

is based on the Goodrich Corporation’s 

average price of $6,000 per ice detector 

for a production airplane. The Aviation 

Rulemaking Advisory Committee 

(ARAC) Ice Protection Harmonization 

Working Group provided us with 

manufacturer cost estimates for System 

Design, System Qualification, Hardware, 

Installation, and Maintenance. 

Assuming the primary IDS has two ice 

detectors, we estimate the average cost 

for a primary IDS to be about $485,000 

per certification, $12,000 ($6,000 × 2) 

for the hardware and $2,500 for the 

installation, or $14,500 ($12,000 + 

$2,500) per airplane. Table 1 shows a 

detailed breakout of these cost 

estimates. 

One commenter to the NPRM, 

regarding Goodrich costs, stated there 

was a cheaper alternative system than 

the Goodrich system. The FAA notes a 

lower cost alternative is feasible. 

TABLE 1—COSTS FOR § 25.1419(E)(1)—PRIMARY ICE DETECTION SYSTEM

Manufacturer non-recurring costs (per aircraft group/type) 2006$ Hours Hourly rate Additional 

cost Cost 

System Design: 

System architecture/Integration ................................................................................ 3,000 $75 .................... $225,000 

Ice detector positioning ............................................................................................ 300 75 .................... 22,500 

Procedures for AFM, AOM/FCOM & MMEL ............................................................ 200 75 .................... 15,000 

System Qualification/certification: 

Ice detector qualification ........................................................................................... 300 75 .................... 22,500 

Ice detection system certification ............................................................................. 600 75 .................... 45,000 

Flight tests ................................................................................................................ 400 75 100,000 130,000 

Installation Design: 

Installation drawings ................................................................................................. 500 50 .................... 25,000 

Total ................................................................................................................... 5,300 .................... .................... 485,000 

Costs (per airplane): 

Hardware (Primary Ice Detection System) ............................................................... .................... .................... 12,000 12,000 

Installation ................................................................................................................. 50 50 .................... 2,500 

Additional weight is 5–10 kg .................................................................................... .................... .................... .................... 0 

Total ................................................................................................................... .................... .................... .................... 14,500 

The second method of ice detection is 

the use of an advisory IDS along with 

visual cues. The major difference 

between a primary and an advisory IDS 

is that the primary is the principal 

means to determine when the airframe 

IPS should be activated and has two ice 

detectors. In contrast, an advisory IDS is 

a backup to the flightcrew and has only 

one ice detector. The average cost for an 

advisory IDS is estimated to be $447,500 

per certification, $6,000 for the 

hardware and $1,250 for the 

installation, or $7,250 ($6,000 + $1,250) 

per airplane. Table 2 shows a detailed 

breakout of these costs estimates. 

TABLE 2—COSTS FOR § 25.1419(E)(2)—ADVISORY ICE DETECTION SYSTEM AND VISUAL CUES

Manufacturer non-recurring costs (per aircraft group/type) 2006$ Hours Hourly rate Additional 

cost Cost 

System Design: 

System architecture/Integration ................................................................................ 2,500 $75 .................... $187,500 

Ice detector positioning ............................................................................................ 200 75 .................... 15,000 

Visual cue determination/design .............................................................................. 200 75 .................... 15,000 

Procedures for AFM, AOM/FCOM & MMEL ............................................................ 200 75 .................... 15,000 

System Qualification/certification: 

Ice detection qualification ......................................................................................... 300 75 .................... 22,500 

Visual cue substantiation .......................................................................................... 200 75 .................... 15,000 

Ice detection system certification ............................................................................. 300 75 .................... 22,500 

Flight tests ................................................................................................................ 400 75 $100,000 130,000 

Installation Design: 

Installation drawings ................................................................................................. 500 50 .................... 25,000 

Total ................................................................................................................... 4,800 .................... .................... 447,500 

Costs (per airplane): 

Hardware (Advisory Ice Detection System) ............................................................. .................... .................... 6,000 6,000 

Installation ................................................................................................................. 25 50 .................... 1,250 

Additional weight is 5–10 kg .................................................................................... .................... .................... .................... 0 

Total ................................................................................................................... .................... .................... .................... 7,250 

The third method of ice detection is 

a definition of conditions conducive to 

airframe icing that will be used by the 

flightcrew to activate the airframe IPS. 

This definition will be included in the 

Airplane Flight Manual. There are no 


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11Type Certification Data Sheet No. A22CE. 

costs imposed on the airplane 

manufacturers with this option. Table 3 

shows a summary of the costs for each 

alternative. 

TABLE 3—COST SUMMARY—§ 25.1419(E) 

Costs 

Per certification Per airplane 

§ 25.1419 Alternatives: 

(e)(1) Primary IDS .................................................................................................................................. $485,000 $14,500 

(e)(2) Advisory IDS and Visual Cues ..................................................................................................... 447,500 7,250 

(e)(3) Temperature and Moisture ........................................................................................................... 0 0 

The least cost alternative is to activate 

the airframe IPS whenever the airplane 

is operating in conditions conducive to 

airframe icing based on a specific air 

temperature threshold and the presence 

of visible moisture. Since there are no 

additional certification or production 

costs to manufacturers by complying 

with § 25.1419(e)(3) through this 

alternative, we have determined there 

are no costs associated with compliance 

with § 25.1419(e). 

We are aware some manufacturers 

may choose to install more complex 

systems ((e)(1) or (e)(2)), and want to 

note these more complex systems are 

acceptable alternatives to (e)(3). 

§ 25.1419(f) 

Section 25.1419(f) describes the 

applicability of the final rule to all 

phases of flight, so there are no 

additional costs associated with this 

section. 

§ 25.1419(g) 

After the initial operation of the 

airframe IPS, § 25.1419(g) provides 

alternatives the manufacturer must 

provide to the operator for safe flight. 

These alternatives are: 

• The IPS must be designed to 

operate continuously (§ 25.1419(g)(1)), 

or 

• The airplane must be equipped 

with a system that automatically cycles 

the IPS (§ 25.1419(g)(2)), or 

• An IDS must be provided to alert 

the flightcrew each time the IPS must be 

cycled (§ 25.1419(g)(3)). 

Section 25.1419(g) applies to 

airplanes with either a thermal antiicing IPS or an IPS that operates in a 

cyclical manner. Thermal anti-icing 

systems typically operate continuously 

while deicing systems usually operate 

cyclically. 

Section 25.1419(g)(1) applies 

primarily to a thermal anti-icing IPS, 

which typically uses heat to keep 

protected surfaces of the airplane free of 

ice accretions. 

No additional manufacturing costs are 

associated with § 25.1419(g)(1) because, 

once a thermal anti-IPS is activated, it 

is capable of operating continuously. 

The cost estimates for each option do 

not include primary and advisory ice 

detection system maintenance, which 

would make the costs for these 

alternatives higher. The FAA has 

determined that the trend for new part 

25 aircraft certification is toward antiice protection systems so the 

maintenance costs associated with 

deicing ice protection systems are not 

considered. The cost estimates for 

§ 25.1419(g)(1) do not include the 

associated maintenance costs for antiice protection systems as operators are 

already incurring these costs. 

Sections 25.1419(g)(2) and (3) apply 

to an airframe IPS that operates in a 

cyclical manner. Past delivery history 

has shown that about 97% of U.S. 

manufactured part 25 airplanes 

delivered have thermal anti-icing IPS 

and 3% have deicing IPSs that operate 

in a cyclical manner. Cessna is the only 

U.S. manufacturer that currently 

delivers part 25 certificated airplanes 

with an IPS that operates in a cyclical 

manner. Those airplanes were 

certificated in September 1971.11 Newer 

variants of airplanes from that 

September 1971 type certificate and all 

newer part 25 new Cessna certifications 

have thermal anti-icing IPS that operate 

continuously. We believe the trend for 

new part 25 aircraft certifications is 

toward a thermal anti-icing IPS that 

operates continuously. Because of the 

trend of part 25 manufacturers to install 

thermal anti-icing IPS in their newly 

certificated part 25 airplanes, we believe 

there are no costs imposed on the 

airplane manufacturers by § 25.1419(g). 

Bombardier indicated future 

technology may reintroduce cyclical 

deicing systems. No U.S. manufacturer 

has certificated cyclical deicing systems 

since 1971. Since recent part 23 Very 

Light Jet (VLJ) certification programs 

have automatic cyclical deicing systems, 

we do not anticipate airplane 

manufacturers to certificate manuallycycled deicing systems. 

We received no comments from U.S. 

manufacturers on their plans to produce 

a newly part 25 certificated aircraft with 

deicing systems that operate cyclically 

and the associated certification costs; 

therefore, we believe § 25.1419(g) will 

add no additional costs. 

§ 25.1419(h) 

Future Airplane Flight Manuals can 

be readily prepared to include 

appropriate icing procedures for future 

certificated air transport category 

airplanes. Thus, minimal costs are 

associated with § 25.1419(h). 

B. Benefits 

The FAA is adopting this final rule 

because accidents and incidents 

occurred where the flightcrew did not 

operate the airframe IPS in a timely 

manner and because of concerns over 

the flightcrew workload required to 

operate an airframe IPS that the 

flightcrew must manually cycle. The 

final rule addresses these concerns by 

ensuring that flightcrews are provided 

with a clear means to know when to 

activate the airframe IPS and by 

reducing the workload associated with 

an airframe IPS that operates cyclically. 

The safety benefit of this final rule is 

that it will improve the level of safety 

of new airplane designs for operations 

in icing conditions. 

C. Conclusions 

The FAA has determined that this 

final rule has benefits that justify its 

minimal costs. However, the Office of 

Management and Budget has 

determined that this final rule is a 

‘‘significant regulatory action,’’ because 

it harmonizes U.S. aviation standards 

with those of other civil aviation 

authorities. 

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 


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38338 Federal Register / Vol. 74, No. 147 / Monday, August 3, 2009 / Rules and Regulations 

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-forprofit organizations, and small 

governmental jurisdictions. 

Agencies must perform a review to 

determine whether a rule will have a 

significant economic impact on a 

substantial number of small entities. If 

the agency determines that it will, the 

agency must prepare a regulatory 

flexibility analysis as described in the 

RFA. 

However, if an agency determines that 

a rule is not expected to have a 

significant economic impact on a 

substantial number of small entities, 

section 605(b) of the RFA provides that 

the head of the agency may so certify 

and a regulatory flexibility analysis is 

not required. The certification must 

include a statement providing the 

factual basis for this determination, and 

the reasoning should be clear. 

As we stated in the NPRM, all United 

States transport category aircraft 

manufacturers exceed the Small 

Business Administration small-entity 

criteria of 1,500 employees. We received 

no public comments disputing this 

determination. 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) prohibits Federal 

agencies from establishing any 

standards or engaging in related 

activities that create unnecessary 

obstacles to the foreign commerce of the 

United States. Legitimate domestic 

objectives, such as safety, are not 

considered unnecessary obstacles. The 

statute also requires consideration of 

international standards and, where 

appropriate, that they be the basis for 

U.S. standards. The FAA has assessed 

the potential effect of this final rule and 

has no basis for believing the rule will 

impose substantially different costs on 

domestic and international entities. 

Thus the FAA believes the rule has a 

neutral trade impact. 

Unfunded Mandates Assessment 

Title II of the Unfunded Mandates 

Reform Act of 1995 (Pub. L. 104–4) 

requires each Federal agency to prepare 

a written statement assessing the effects 

of any Federal mandate in a proposed or 

final agency rule that may result in an 

expenditure of $100 million or more (in 

1995 dollars) in any one year by State, 

local, and Tribal governments, in the 

aggregate, or by the private sector; such 

a mandate is deemed to be a ‘‘significant 

regulatory action.’’ The FAA currently 

uses an inflation-adjusted value of 

$136.1 million in lieu of $100 million. 

This 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 

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 4(j) 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 a 

‘‘significant regulatory action,’’ 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 amendment number 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 1—Definition of Terms Used 

in This Preamble 

For the preamble of this rulemaking, the 

following definitions are applicable. These 

definitions of terms are for use only with this 

rulemaking’s preamble: 

a. Advisory ice detection system: An 

advisory ice detection system annunciates 


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the presence of icing conditions or ice 

accretion. The advisory ice detection system 

provides information advising the flightcrew 

of the presence of ice accretion or icing 

conditions. An advisory ice detection system 

differs from a primary ice detection system 

in that it usually consists of a single ice 

detector without redundancies that provide 

sufficient reliability to comply with 

§ 25.1309. Therefore, it 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. The flightcrew is responsible for 

monitoring the icing conditions or ice 

accretion as defined in the AFM (typically 

using total air temperature and visible 

moisture criteria or visible ice accretion) and 

activating the anti-icing or deicing system(s). 

b. Airframe icing: Airframe icing is ice 

accretions on the airplane, except for the 

propulsion system. 

c. Anti-icing: Anti-icing is the prevention 

of ice accretions on a protected surface, 

either: 

• By evaporating the impinging water; or 

• By allowing it to run back and off the 

protected surface or freeze on non-critical 

areas. 

d. Automatic cycling mode: An automatic 

cycling mode is a mode of operation of the 

airframe deicing 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. Deicing: Deicing is the removal or the 

process of removal of an ice accretion after 

it has formed on a surface. 

f. Ice Protection System: An ice protection 

system (IPS) is a system that protects certain 

critical aircraft parts from ice accretion. To be 

an approved system, it must satisfy the 

requirements of § 25.1419. 

g. Primary ice detection system: A primary 

ice detection system is used to determine 

when the IPS must be activated. A primary 

ice detection system is a system with 

redundancies that provide sufficient 

reliability to comply with § 25.1309 so the 

flight crew does not need to visually monitor 

the icing accretions that may be building on 

the airplane. The system annunciates the 

presence of ice accretion or icing conditions, 

and may also provide information to other 

aircraft systems. A primary automatic system 

automatically activates the anti-icing or 

deicing IPS. With a primary manual system, 

the flightcrew activates the anti-icing or 

deicing IPS upon indication from the primary 

ice detection system. 

h. Static air temperature: The air 

temperature as would be measured by a 

temperature sensor not in motion with 

respect to that air. This temperature is also 

referred to in other documents as ‘‘outside air 

temperature,’’ ‘‘true outside temperature,’’ or 

‘‘ambient temperature.’’ 

i. Total air temperature: The temperature 

of a parcel of air brought to rest relative to 

the aircraft resulting from adiabatic 

compression of the parcel. This temperature 

is also referred to in other documents as 

‘‘stagnation temperature.’’ 

List of Subjects in 14 CFR Part 25 

Aircraft, Aviation safety, Reporting 

and recordkeeping requirements, Safety, 

Transportation. 

The Amendment 

■ In consideration of the foregoing, the 

Federal Aviation Administration 

amends Part 25 of Title 14, Code of 

Federal Regulations as follows: 

PART 25—AIRWORTHINESS 

STANDARDS, TRANSPORT 

CATEGORY AIRPLANES 

■ 1. The authority citation for part 25 

continues to read as follows: 

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

44702, and 44704. 

■ 2. Amend § 25.143 by revising 

paragraph (j) to read as follows: 

§ 25.143 General. 

* * * * * 

(j) For flight in icing conditions before 

the ice protection system has been 

activated and is performing its intended 

function, it must be demonstrated in 

flight with the ice accretion defined in 

appendix C, part II(e) of this part that: 

(1) The airplane is controllable in a 

pull-up maneuver up to 1.5 g load 

factor; and 

(2) There is no pitch control force 

reversal during a pushover maneuver 

down to 0.5 g load factor. 

■ 3. Amend § 25.207 by revising 

paragraphs (b) and (h), and adding a 

new paragraph (i) to read as follows: 

§ 25.207 Stall warning. 

* * * * * 

(b) The warning must be furnished 

either through the inherent aerodynamic 

qualities of the airplane or by a device 

that will give clearly distinguishable 

indications under expected conditions 

of flight. However, a visual stall warning 

device that requires the attention of the 

crew within the cockpit is not 

acceptable by itself. If a warning device 

is used, it must provide a warning in 

each of the airplane configurations 

prescribed in paragraph (a) of this 

section at the speed prescribed in 

paragraphs (c) and (d) of this section. 

Except for showing compliance with the 

stall warning margin prescribed in 

paragraph (h)(3)(ii) of this section, stall 

warning for flight in icing conditions 

must be provided by the same means as 

stall warning for flight in non-icing 

conditions. 

* * * * * 

(h) For flight in icing conditions 

before the ice protection system has 

been activated and is performing its 

intended function, with the ice 

accretion defined in appendix C, part 

II(e) of this part, the stall warning 

margin in straight and turning flight 

must be sufficient to allow the pilot to 

prevent stalling without encountering 

any adverse flight characteristics when: 

(1) The speed is reduced at rates not 

exceeding one knot per second; 

(2) The pilot performs the recovery 

maneuver in the same way as for flight 

in non-icing conditions; and 

(3) The recovery maneuver is started 

no earlier than: 

(i) One second after the onset of stall 

warning if stall warning is provided by 

the same means as for flight in non-icing 

conditions; or 

(ii) Three seconds after the onset of 

stall warning if stall warning is 

provided by a different means than for 

flight in non-icing conditions. 

(i) In showing compliance with 

paragraph (h) of this section, if stall 

warning is provided by a different 

means in icing conditions than for nonicing conditions, compliance with 

§ 25.203 must be shown using the 

accretion defined in appendix C, part 

II(e) of this part. Compliance with this 

requirement must be shown using the 

demonstration prescribed by § 25.201, 

except that the deceleration rates of 

§ 25.201(c)(2) need not be demonstrated. 

■ 4. Amend § 25.1419 by adding new 

paragraphs (e), (f), (g), and (h) to read as 

follows: 

§ 25.1419 Ice protection. 

* * * * * 

(e) One of the following methods of 

icing detection and activation of the 

airframe ice protection system must be 

provided: 

(1) A primary ice detection system 

that automatically activates or alerts the 

flightcrew to activate the airframe ice 

protection system; 

(2) A definition of visual cues for 

recognition of the first sign of ice 

accretion on a specified surface 

combined with an advisory ice 

detection system that alerts the 

flightcrew to activate the airframe ice 

protection system; or 

(3) Identification of conditions 

conducive to airframe icing as defined 

by an appropriate static or total air 

temperature and visible moisture for use 

by the flightcrew to activate the airframe 

ice protection system. 

(f) Unless the applicant shows that the 

airframe ice protection system need not 

be operated during specific phases of 

flight, the requirements of paragraph (e) 

of this section are applicable to all 

phases of flight. 

(g) After the initial activation of the 

airframe ice protection system— 


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(1) The ice protection system must be 

designed to operate continuously; 

(2) The airplane must be equipped 

with a system that automatically cycles 

the ice protection system; or 

(3) An ice detection system must be 

provided to alert the flightcrew each 

time the ice protection system must be 

cycled. 

(h) Procedures for operation of the ice 

protection system, including activation 

and deactivation, must be established 

and documented in the Airplane Flight 

Manual. 

■ 5. Amend appendix C to part 25 by 

revising part II (e) to read as follows: 

Appendix C to Part 25 

* * * * * 

Part II—Airframe Ice Accretions for Showing 

Compliance With Subpart B 

* * * * * 

(e) The ice accretion before the ice 

protection system has been activated and is 

performing its intended function is the 

critical ice accretion formed on the 

unprotected and normally protected surfaces 

before activation and effective operation of 

the ice protection system in continuous 

maximum atmospheric icing conditions. This 

ice accretion only applies in showing 

compliance to §§ 25.143(j) and 25.207(h), and 

25.207(i). 

Issued in Washington, DC, on July 17, 

2009. 

Lynne A. Osmus, 

Acting Administrator. 

[FR Doc. E9–18483 Filed 7–31–09; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2009–0227; Directorate 

Identifier 2007–SW–65–AD; Amendment 39– 

15978; AD 2009–15–15] 

RIN 2120–AA64 

Airworthiness Directives; Bell 

Helicopter Textron Canada Model 427 

Helicopters 

AGENCY: Federal Aviation 

Administration (FAA), Department of 

Transportation (DOT). 

ACTION: Final rule. 

SUMMARY: We are adopting a new 

airworthiness directive (AD) for Bell 

Helicopter Textron Canada (BHTC) 

Model 427 helicopters. This AD results 

from mandatory continuing 

airworthiness information (MCAI) 

originated by the aviation authority of 

Canada to identify and correct an unsafe 

condition on an aviation product. 

Transport Canada, the aviation authority 

of Canada, with which we have a 

bilateral agreement, states that it has 

been determined that the existing 

hardware connecting the vertical fin to 

the tail rotor gearbox needs to be 

upgraded to prevent the vertical fin 

from becoming loose. 

BHTC has received reports of loose 

vertical fins discovered during 

inspections. Investigation revealed that 

the current vertical fin attachment 

hardware may not provide adequate 

clamp-up. If not corrected, the vertical 

fin could become loose and cause 

vibration, which could lead to 

subsequent loss of control of the 

helicopter. This AD requires actions that 

are intended to address this unsafe 

condition. 

DATES: This AD becomes effective on 

September 8, 2009. 

ADDRESSES: You may examine the AD 

docket on the Internet at http:// 

regulations.gov or in person at the 

Docket Operations office, U.S. 

Department of Transportation, M–30, 

West Building Ground Floor, Room 

W12–140, 1200 New Jersey Avenue, SE., 

Washington, DC between 9 a.m. and 5 

p.m. Monday through Friday, except 

Federal holidays. 

You may get the service information 

identified in this AD from Bell 

Helicopter Textron Canada Limited, 

12,800 Rue de l’Avenir, Mirabel, Quebec 

J7J1R4, telephone (450) 437–2862 or 

(800) 363–8023, fax (450) 433–0272, or 

at http://www.bellcustomer.com/files/. 

Examining the AD Docket: The AD 

docket contains the Notice of proposed 

rulemaking (NPRM), the economic 

evaluation, any comments received, and 

other information. The street address 

and operating hours for the Docket 

Operations office (telephone (800) 647– 

5527) are in the ADDRESSES section of 

this AD. Comments will be available in 

the AD docket shortly after they are 

received. 

FOR FURTHER INFORMATION CONTACT: 

Sharon Miles, Aviation Safety Engineer, 

FAA, Rotorcraft Directorate, Regulations 

and Guidance Group, 2601 Meacham 

Blvd., Fort Worth, Texas 76137, 

telephone (817) 222–5122, fax (817) 

222–5961. 

SUPPLEMENTARY INFORMATION: 

Discussion 

We issued an NPRM to amend 14 CFR 

part 39 to include an AD that would 

apply to BHTC Model 427 helicopters 

on March 4, 2009. That NPRM was 

published in the Federal Register on 

March 23, 2009 (74 FR 12098). That 

NPRM proposed to require actions to 

prevent the vertical fin from becoming 

loose and causing vibration, which 

could lead to subsequent loss of control 

of the helicopter. You may obtain 

further information by examining the 

MCAI and any related service 

information in the AD docket. 

Comments 

By publishing the NPRM, we gave the 

public an opportunity to participate in 

developing this AD. However, we 

received no comment on the NPRM or 

on our determination of the cost to the 

public. Therefore, based on our review 

and evaluation of the available data, we 

have determined that air safety and the 

public interest require adopting the AD 

as proposed. 

Relevant Service Information 

Bell Helicopter Textron has issued 

Alert Service Bulletin No. 427–06–15, 

dated December 14, 2006. The actions 

described in the MCAI are intended to 

correct the same unsafe condition as 

that identified in the service 

information. 

Differences Between This AD and the 

MCAI AD 

We have reviewed the MCAI AD and 

related service information and, in 

general, agree with their substance. This 

AD differs from the MCAI AD as 

follows: 

• We do not require compliance ‘‘no 

later than November 27, 2007’’, because 

that date has passed. 

• We refer to the compliance time as 

‘‘hours time-in-service’’ rather than ‘‘air 

time hours.’’ 

These differences are highlighted in 

the ‘‘Differences Between this AD and 

the MCAI AD’’ section in the AD. 

Costs of Compliance 

We estimate that this AD will affect 

about 17 products of U.S. registry. We 

also estimate that it will take about 2 

work-hours per helicopter to remove 

and visually inspect the vertical fin and 

the tail rotor gearbox attachment legs 

and to re-install the vertical fin. The 

average labor rate is $80 per work-hour. 

Required parts will cost about $227 per 

helicopter. Based on these figures, we 

estimate the cost of this AD on U.S. 

operators to be $6,579 for the fleet, or 

$387 per helicopter, to perform the 

inspections and remove and re-install 

the vertical fin. 

Authority for This Rulemaking 

Title 49 of the United States Code 

specifies the FAA’s authority to issue 

rules on aviation safety. Subtitle I, 

section 106, describes the authority of 

the FAA Administrator. ‘‘Subtitle VII: 


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