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contains regulatory documents having general

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are keyed to and codified in the Code of

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Rules and Regulations Federal Register

59423 

Vol. 79, No. 191 

Thursday, October 2, 2014 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 25 

[Docket No.: FAA–2013–0109; Amdt. No. 

25–139] 

RIN 2120–AK13 

Harmonization of Airworthiness 

Standards—Miscellaneous Structures 

Requirements 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Final rule. 

SUMMARY: This final rule amends certain 

airworthiness regulations for transport 

category airplanes, based on 

recommendations from the FAAsponsored Aviation Rulemaking 

Advisory Committee (ARAC). This 

amendment eliminates regulatory 

differences between the airworthiness 

standards of the FAA and the European 

Aviation Safety Agency (EASA). This 

final rule does not add new 

requirements beyond what 

manufacturers currently meet for EASA 

certification and does not affect current 

industry design practices. This final rule 

revises the structural test requirements 

necessary when analysis has not been 

found reliable; clarifies the quality 

control, inspection, and testing 

requirements for critical and noncritical castings; adds control system 

requirements that consider structural 

deflection and vibration loads; expands 

the fuel tank structural and system 

requirements regarding emergency 

landing conditions and landing gear 

failure conditions; adds a requirement 

that engine mount failure due to 

overload must not cause hazardous fuel 

spillage; and revises the inertia forces 

requirements for cargo compartments by 

removing the exclusion of 

compartments located below or forward 

of all occupants in the airplane. 

DATES: Effective December 1, 2014. 

ADDRESSES: For information on where to 

obtain copies of rulemaking documents 

and other information related to this 

final rule, see ‘‘How to Obtain 

Additional Information’’ in the 

SUPPLEMENTARY INFORMATION section of 

this document. 

FOR FURTHER INFORMATION CONTACT: For 

technical questions concerning this 

action, contact Todd Martin, Airframe 

and Cabin Safety Branch, ANM–115, 

Transport Airplane Directorate, Aircraft 

Certification Service, Federal Aviation 

Administration, 1601 Lind Avenue SW., 

Renton, WA 98057–3356; telephone 

(425) 227–1178; facsimile (425) 227– 

1232; email Todd.Martin@faa.gov. 

For legal questions concerning this 

action, contact Sean Howe, Office of the 

Regional Counsel, ANM–7, Federal 

Aviation Administration, 1601 Lind 

Avenue SW., Renton, Washington 

98057–3356; telephone (425) 227–2591; 

facsimile (425) 227–1007; email 

Sean.Howe@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 regulations 

and minimum standards for the design 

and performance of aircraft that the 

Administrator finds necessary for safety 

in air commerce. This regulation is 

within the scope of that authority. It 

prescribes new safety standards for the 

design of transport category airplanes. 

I. Overview of Final Rule 

The FAA is amending Title 14, Code 

of Federal Regulations (14 CFR) 

25.307(a), 25.621, 25.683, 25.721, 

25.787(a), 25.963(d), and 25.994 as 

described below. This action 

harmonizes part 25 requirements with 

the corresponding requirements in Book 

1 of the EASA Certification 

Specifications and Acceptable Means of 

Compliance for Large Aeroplanes (CS– 

25). 

1. Section 25.307(a), ‘‘Proof of 

structure,’’ currently requires structural 

strength testing, unless the applicant 

has demonstrated that analysis alone is 

reliable. Paragraph (a) is revised to 

clarify the load levels to which testing 

is required, when such testing is 

required. 

2. Section 25.621, ‘‘Casting factors,’’ is 

revised to clarify the quality control, 

inspection, and testing requirements for 

critical and non-critical castings. 

3. Section 25.683, ‘‘Operation tests,’’ 

is revised to add a requirement that— 

• The control system must remain 

free from jamming, friction, 

disconnection, and permanent damage 

in the presence of structural deflection 

and 

• Under vibration loads, no hazard 

may result from interference or contact 

of the control system with adjacent 

elements. 

4. Section 25.721, ‘‘Landing Gear— 

General,’’ is revised to— 

• Expand the landing gear failure 

conditions to include side loads, in 

addition to up and aft loads, and expand 

this requirement to include nose 

landing gear in addition to the main 

landing gear, 

• Specify that the wheels-up landing 

conditions are assumed to occur at a 

descent rate of 5 feet per second, 

• Add a sliding-on-ground condition, 

and 

• Require the engine mount be 

designed so that, when it fails due to 

overload, this failure does not cause the 

spillage of enough fuel to constitute a 

fire hazard. 

5. Section 25.787, ‘‘Stowage 

compartments,’’ is revised to expand the 

inertia forces requirements for cargo 

compartments by removing the 

exclusion of compartments located 

below or forward of all occupants in the 

airplane. 

6. Section 25.963, ‘‘Fuel tanks: 

general,’’ is revised to— 

• Require that fuel tanks be designed 

so that no fuel is released in or near the 

fuselage, or near the engines, in 

quantities that would constitute a fire 

hazard in otherwise survivable 

emergency landing conditions, 

• Define fuel tank pressure loads for 

fuel tanks located within and outside 

the fuselage pressure boundary and near 

the fuselage or near the engines, and 


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59424 Federal Register / Vol. 79, No. 191 / Thursday, October 2, 2014 / Rules and Regulations 

• Specify the wheels-up landing 

conditions and landing gear and engine 

mount failure conditions that must be 

considered when evaluating fuel tank 

structural integrity. 

7. Section 25.994, ‘‘Fuel system 

components,’’ is revised to specify the 

wheels-up landing conditions to be 

considered when evaluating fuel system 

components. 

II. Background 

A. Statement of the Problem 

Part 25 of 14 CFR prescribes 

airworthiness standards for type 

certification of transport category 

airplanes, for products certified in the 

United States. EASA CS–25 Book 1 

prescribes the corresponding 

airworthiness standards for products 

certified in Europe. While part 25 and 

CS–25 Book 1 are similar, they differ in 

several respects. To resolve those 

differences, the FAA tasked ARAC 

through the Loads and Dynamics 

Harmonization Working Group 

(LDHWG) and the General Structures 

Harmonization Working Group 

(GSHWG) to review existing structures 

regulations and recommend changes 

that would eliminate differences 

between the U.S. and European 

airworthiness standards. The LDHWG 

and GSHWG developed 

recommendations, which EASA has 

incorporated into CS–25 with some 

changes. The FAA agrees with the 

ARAC recommendations as adopted by 

EASA, and this final rule amends part 

25 accordingly. 

B. Summary of the NPRM 

On February 14, 2013, the FAA issued 

a Notice of Proposed Rulemaking 

(NPRM), Notice No. 25–137, Docket No. 

FAA–2013–0109, to amend §§ 25.307(a), 

25.621, 25.683, 25.721, 25.787(a), 

25.963(d), and 25.994. That NPRM was 

published in the Federal Register on 

March 1, 2013 (78 FR 13835). (The 

NPRM Notice No. was corrected to ‘‘13– 

03’’ in the Federal Register on April 16, 

2014 (79 FR 21413)). In the NPRM, the 

FAA proposed to (1) revise the 

structural test requirements necessary 

when analysis has not been found 

reliable; (2) clarify the quality control, 

inspection, and testing requirements for 

critical and non-critical castings; (3) add 

control system requirements that 

consider structural deflection and 

vibration loads; (4) expand the fuel tank 

structural and system requirements 

regarding emergency landing conditions 

and landing gear failure conditions; (5) 

add a requirement that engine mount 

failure due to overload must not cause 

hazardous fuel spillage; and (6) revise 

the inertial forces requirements for cargo 

compartments by removing the 

exclusion of compartments located 

below or forward of all occupants in the 

airplane. The FAA proposed these 

changes to eliminate regulatory 

differences between the airworthiness 

standards of the FAA and EASA. The 

NPRM comment period closed on May 

30, 2013. 

C. General Overview of Comments 

The FAA received 16 comments from 

5 commenters. All commenters 

generally support the proposal, but they 

suggested changes discussed more fully 

below. The FAA received comments on 

each of the sections being changed, as 

follows: 

• Section 25.307(a)—four comments 

• Section 25.621—four comments 

• Section 25.683—one comment 

• Section 25.721—one comment 

• Section 25.787(a)—two comments 

• Section 25.963(d)—three comments 

• Section 25.994—one comment 

III. Discussion of Public Comments and 

Final Rule 

A. Section 25.307, Proof of Structure 

In the NPRM, the FAA proposed 

revising paragraph (a) of § 25.307 to 

require that, when structural analysis 

has not been shown to be reliable, 

substantiating tests must be made to 

load levels that are sufficient to verify 

structural behavior up to limit and 

ultimate loads of § 25.305. 

One commenter stated that § 25.305 

includes both limit and ultimate loads, 

so it is unclear which ‘‘loads’’ were 

intended by this change. More 

importantly, ‘‘up to’’ could mean any 

load level below limit or below ultimate 

and as such is indefinite. For example, 

an applicant could choose a load level 

of 10 percent of limit load and be in 

compliance with the proposed rule. The 

commenter proposed changing ‘‘up to 

loads specified in § 25.305’’ to ‘‘at least 

limit load as specified in § 25.305.’’ 

The FAA believes the wording 

proposed in the NPRM is correct, and 

no change is necessary. The phrase ‘‘up 

to’’ does not apply to the test load level; 

it applies to the design load level—the 

loads specified in § 25.305, including 

ultimate loads—which must be verified. 

The intent of the rule is that, when 

analysis has not been shown to be 

reliable, tests must be conducted to 

‘‘sufficient’’ load levels. Normally, 

testing to ultimate load levels is 

required, but when previous relevant 

test evidence can be used to support the 

analysis, a lower level of testing may be 

accepted. The rule allows this 

intermediate level of testing. Advisory 

Circular (AC) 25.307–1, ‘‘Proof of 

Structure,’’ which the FAA is issuing 

concurrently with the final rule, 

provides detailed guidance on means of 

compliance with the rule. 

Another commenter recommended 

changing the word ‘‘reliable’’ in the 

proposed rule to ‘‘dependable and 

conservative.’’ The term ‘‘reliable’’ has 

been in place since this rule was 

originally published in 1965. As stated 

in the NPRM, while the rule has 

changed, the rule intent remains the 

same. We believe ‘‘reliable’’ is 

appropriate and clear, and no change is 

necessary. 

The same commenter also 

recommended noting that, where 

justified, test load levels may be less 

than ultimate. We do not believe this 

change is necessary because it is already 

expressed in the rule that substantiating 

tests must be made to load levels that 

are sufficient to verify structural 

behavior up to loads specified in 

§ 25.305. 

The same commenter also 

recommended the FAA add further 

explanation about the absolute need to 

validate models and when lack of 

validation might be acceptable. We do 

not believe it is necessary to revise the 

rule to address validation, since that 

subject relates to the acceptability of an 

applicant’s showing of compliance 

rather than to the airworthiness 

standard itself. This subject is 

thoroughly addressed in the 

accompanying AC 25.307–1. We have 

not revised the final rule in this regard. 

B. Section 25.621, Casting Factors 

With this rulemaking, the FAA 

clarifies ‘‘critical castings’’ as each 

casting whose failure could preclude 

continued safe flight and landing of the 

airplane or could result in serious injury 

to occupants. One commenter agreed 

that improved foundry methods have 

resulted in higher quality castings but 

not to the point where a casting factor 

less than 1.25 is justified. The 

commenter recommended to either (1) 

eliminate the option for casting factors 

of 1.0 for critical castings, or (2) ensure 

that the characterization of material 

properties that are equivalent to those of 

wrought alloy products of similar 

composition includes the effect of 

defects in the static strength, fatigue, 

and damage tolerance requirements. The 

commenter provided the following 

examples of defects that could affect 

material properties: shell defects, hardalpha contamination, shrink, porosity, 

weld defects, grain size, hot tears, 

incomplete densifications, and prior 

particle boundaries, among others. 


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Federal Register / Vol. 79, No. 191 / Thursday, October 2, 2014 / Rules and Regulations 59425 

The FAA does not agree with the 

commenter’s first recommendation to 

eliminate the option for using a casting 

factor of 1.0 for critical castings. The 

criteria specified in the final rule will 

ensure product quality that is sufficient 

to justify using a casting factor of 1.0. 

According to the rule, to qualify for a 

casting factor of 1.0, the applicant must 

demonstrate, through process 

qualification, proof of product, and 

process monitoring, that the casting has 

coefficients of variation of the material 

properties that are equivalent to those of 

wrought alloy products of similar 

composition. The rule requires process 

monitoring that includes testing of 

coupons and, on a sampling basis, 

coupons cut from critical areas of 

production castings. In addition, the 

applicant must inspect 100 percent of 

the casting surface of each casting, as 

well as structurally significant internal 

areas and areas where defects are likely 

to occur. The applicant must also test 

one casting to limit and ultimate loads. 

The purpose of the minimum casting 

factor of 1.25 in the current rule is to 

increase the strength of the casting to 

account for variability in the casting 

process. In the final rule, the additional 

process, inspection, and test 

requirements required to use a casting 

factor less than 1.25 ensure a more 

consistent product and maintain the 

same level of safety as the existing 

standards. AC 25.621–1, ‘‘Casting 

Factors,’’ provides detailed guidance on 

the premium casting process necessary 

to allow a casting factor of 1.0, and the 

FAA is issuing that AC concurrently 

with this final rule. 

The FAA partially agrees with the 

commenter’s second recommendation, 

which is to ensure that the 

characterization of material properties 

that are equivalent to those of wrought 

alloy products of similar composition 

includes the effect of defects in the 

static strength, fatigue, and damage 

tolerance requirements. The rule 

requires that the characterization of 

material properties includes the effect of 

defects with regard to static strength. If 

any type of defect is discovered during 

process qualification, proof of product, 

or process monitoring, or by any 

inspection or static strength test, such 

that the coefficients of variation of the 

material properties are not equivalent to 

those of wrought alloy products of 

similar composition, then that casting 

would not qualify for a casting factor of 

1.0. These defects include each of the 

examples identified by the commenter, 

as well as any other type of defect that 

could affect material properties. In 

addition, as noted previously, AC 

25.621–1, which the FAA is issuing 

concurrently with the final rule, 

provides detailed guidance on the 

premium casting process necessary to 

allow a casting factor of 1.0. The AC 

includes reference to and addresses 

defects as proposed by the commenter. 

We do not, however, agree that the 

characterization of material properties 

to determine the appropriate casting 

factor should include the effect of 

defects on fatigue and damage tolerance 

properties. Since casting factors apply 

only to strength requirements, rather 

than fatigue and damage tolerance 

requirements, the comparison of cast 

material to wrought material should 

only be based on material strength 

properties, rather than fatigue and 

damage tolerance characteristics. 

Section 25.621(c)(2)(ii)(B) specifies a 

factor of 1.15 be applied to limit load 

test values to allow an applicant to use 

a casting factor of 1.25. Section 

25.621(c)(3)(ii)(B) also specifies a factor 

of 1.15 be applied to limit load test 

values to allow a casting factor of 1.5. 

One commenter recommended that the 

1.15 test factor in § 25.621(c)(3)(ii)(B) be 

scaled up by a factor of 1.2 (1.5/1.25), 

so as to align with the corresponding 

ultimate requirement. The 1.15 limit 

load test factor in § 25.621(c)(3)(ii)(B) 

would then be 1.38 (i.e., 1.5/1.25 × 1.15; 

1.15 being required already in 

conjunction with the 1.25 casting factor 

for ultimate). 

The FAA does not agree that for 

critical castings with a casting factor of 

1.25 or 1.5, the limit load test factor 

should be linked to the ultimate load 

test factor. The ultimate and limit load 

tests have different purposes. The 

ultimate load test confirms ultimate 

load capability, while the limit load test 

confirms that no deformation will occur 

up to a much lower load level. 

Therefore, we see no reason to link the 

two test factors, and we believe the 1.15 

factor specified in § 25.621(c)(3)(ii)(B) is 

appropriate, as recommended by ARAC 

and as currently specified in EASA CS 

25.621. 

The same commenter recommended 

modifying § 25.621(c) by adding a 

reference to § 25.305 for clarity—that 

each critical casting must have a factor 

associated with it for showing 

compliance with the strength and 

deformation requirement ‘‘of § 25.305.’’ 

We agree and have revised the final rule 

as recommended. 

The same commenter noted that 

§ 25.621 only refers to static testing and 

does not include any requirements for 

fatigue testing. The commenter stated 

that critical castings should also comply 

with § 25.571 concerning fatigue and 

damage tolerance. The commenter 

recommended including information to 

remind manufacturers of this 

requirement. The FAA agrees with the 

commenter that § 25.571 applies to 

critical castings. We believe the current 

wording in § 25.571 and the new 

wording in § 25.621 is sufficiently clear 

on this point, and no changes to these 

requirements are necessary. 

No other public comments were 

received on § 25.621. However, after 

further FAA review, we revised the rule 

in several places to specify ‘‘visual 

inspection and liquid penetrant or 

equivalent inspection methods.’’ This 

change is to clarify ‘‘equivalent 

inspection methods’’ refers to the liquid 

penetrant inspection, and not the visual 

inspection. Although there is some 

textual difference between this and CS 

25.621, there is no substantive 

difference between the two harmonized 

rules. 

C. Section 25.683, Operation Tests 

A commenter noted that the control 

systems to which § 25.683(b) applies are 

those control systems that obtain the 

pitch, roll, and yaw limit maneuver 

loads of the airplane structure. For 

example, an applicant must take into 

account the elevator, rudder, and 

aileron because these control surfaces 

obtain the referenced maneuver loads, 

while high lift systems do not need to 

be considered under § 25.683(b). The 

commenter suggested that we clarify 

this in the preamble to the final rule. 

The FAA agrees and hereby clarifies 

that § 25.683 only applies to those 

control systems that are loaded to obtain 

the specified maneuver loads. No 

change to the final rule text is necessary. 

No other public comments were 

received on § 25.683. We would like to 

explain what is meant by ‘‘where 

necessary’’ as used in § 25.683(b). The 

rule states: ‘‘It must be shown by 

analysis and, where necessary, by tests, 

that in the presence of deflections of the 

airplane structure,’’ the control system 

operates without jamming, excessive 

friction, or permanent damage. The FAA 

may accept analysis alone to comply 

with this requirement. However, the 

FAA or the applicant may determine 

that, in certain cases, some testing is 

necessary to verify the analysis. For 

example, some testing may be necessary 

if the structure or control system is 

significantly more complex than a 

previous design, or if the analysis shows 

areas where the control system could be 

susceptible to jamming, friction, 

disconnection or damage. Testing may 

include component testing or full-scale 

tests. 


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D. Section 25.721, Landing Gear— 

General 

A commenter proposed to add a 

paragraph (d) to § 25.721 to state that 

the conditions in paragraphs (a) through 

(c) must be considered regardless of the 

corresponding probabilities. The FAA 

does not believe this addition is 

necessary. The various failure 

conditions in the rule are stated 

directly, and the FAA intended no 

implication that the probability of these 

failure conditions may be taken into 

account. However, because the FAA 

proposed that a failure mode not be 

likely to cause the spillage of enough 

fuel to constitute a fire hazard, the 

proposal may have implied that an 

applicant should take probability into 

account to determine whether the 

failure conditions would lead to fuel 

spillage. The FAA did not intend this. 

Probability should not be taken into 

account to determine whether the 

failure mode will lead to fuel spillage. 

No other public comments were 

received on § 25.721. However, after 

further FAA review, we revised 

§ 25.721(b) to clarify its intent. We 

removed the phrase ‘‘as separate 

conditions,’’ which was proposed in 

§ 25.721(b)(1)(i) and (b)(2)(i), because 

we believe that phrase is confusing. In 

§ 25.721(b)(1)(ii) and (b)(2)(ii), we also 

changed the proposed phrase ‘‘any other 

combination of landing gear legs not 

extended’’ to ‘‘any one or more landing 

gear legs not extended’’ which is the 

same phrase used in § 25.721(b) at 

Amendment 25–32. We made this 

change to ensure that applicants are 

required to address every possible 

combination of landing gear legs not 

extended, including single landing gear 

legs not extended. This is consistent 

with the way EASA has applied its rule. 

Both §§ 25.721(b) and 25.994 final 

rules use the phrase ‘‘wheels-up 

landing.’’ This phrase has been used in 

§ 25.994 since that rule was adopted at 

Amendment 25–23. A ‘‘wheels-up 

landing’’ includes every possible 

combination of landing gear legs not 

extended, including single landing gear 

legs not extended, and all gears fully 

retracted. 

E. Section 25.787, Stowage 

Compartments 

To date, § 25.787(a) has required that 

cargo compartments be designed to the 

emergency landing conditions of 

§ 25.561(b), but excluded compartments 

located below or forward of all 

occupants in the airplane. The FAA 

now revises § 25.787(a) to include 

compartments located below or forward 

of all occupants in the airplane. This 

change would ensure that, in these 

compartments, inertia forces in the up 

and aft direction will not injure 

passengers, and inertia forces in any 

direction will not cause penetration of 

fuel tanks or lines, or cause other 

hazards. 

A commenter recommended revising 

the text to clarify that only those 

specific emergency landing conditions 

that would result in one of the three 

listed effects need to be considered. The 

FAA agrees, and we have revised the 

text to clarify this intent. 

The same commenter suggested that 

fires only need to be protected against 

if they can result in injury to occupants, 

and the rule text should be revised to 

clarify that intent. The FAA does not 

agree that fires only need to be protected 

against if they can result in injury to 

occupants. The FAA believes that the 

wording proposed in the NPRM is 

correct, and no change is necessary. The 

requirement intends protection against 

any fire or explosion on the airplane. 

Although the FAA agrees the objective 

of the rule is to prevent injuries to 

occupants, the FAA considers any fuel 

tank fire or explosion in an otherwise 

survivable landing as potentially injurycausing. 

F. Section 25.963, Fuel Tanks: General 

One commenter suggested that exactly 

the same wording be used in § 25.963(d) 

and CS 25.963(d). EASA CS 25.963(d) 

requires that no fuel be released in 

quantities ‘‘sufficient to start a serious 

fire’’ in otherwise survivable emergency 

landing conditions. Proposed 

§ 25.963(d) would have required that no 

fuel be released in quantities ‘‘that 

would constitute a fire hazard.’’ The 

FAA stated in the NPRM that the two 

phrases have the same meaning, and 

that proposed § 25.963(d) was more 

consistent with the wording of the other 

related sections. 

The FAA is adopting the wording 

proposed in the NPRM as more 

appropriate. As noted in the NPRM, the 

two phrases have the same meaning, 

and the latter phrase is consistent with 

the wording in CS 25.721/§ 25.721, CS 

25.963(d)(4)/§ 25.963(d)(4), and CS 

25.994/§ 25.994. In addition, EASA 

agrees with and supports the NPRM. In 

recent special conditions, the FAA has 

defined a hazardous fuel leak as ‘‘a 

running leak, a dripping leak, or a leak 

that, 15 minutes after wiping dry, 

results in a wetted airplane surface 

exceeding 6 inches in length or 

diameter.’’ We regard this as an 

appropriate definition of the amount of 

fuel that would ‘‘constitute a fire 

hazard’’ as specified in §§ 25.721, 

25.963, and 25.994. 

Another commenter suggested 

modifying § 25.963(d)(5) to reference 

landing gear before engine mounts in 

the rule text, since these are referred to 

respectively in § 25.721(a) and (c). The 

FAA agrees and the recommended 

change has been made. 

EASA CS 25.963(e)(2) provides the 

fire protection criteria for fuel tank 

access covers. A commenter 

recommended that § 25.963(e)(2) be 

revised to match CS 25.963(e)(2), which 

the commenter believes is clearer. The 

FAA notes that this paragraph was not 

addressed in the NPRM and so will not 

be addressed in this final rule. The FAA 

might consider harmonizing this 

paragraph in the future. 

No other public comments were 

received on § 25.963. However, after 

further FAA review, we determined that 

further explanation of the various 

requirements in § 25.963(d) would be 

beneficial. Section 25.963(d), as revised 

by Amendment 25-**, requires that 

‘‘Fuel tanks must, so far as it is 

practicable, be designed, located, and 

installed so that no fuel is released in or 

near the fuselage, or near the engines, in 

quantities that would constitute a fire 

hazard in otherwise survivable 

emergency landing conditions. . . .’’ In 

addition to this primary requirement, 

§ 25.963(d)(1) through (d)(5) provide 

minimum quantitative criteria. 

Survivable landing conditions may 

occur that exceed, or are not captured 

by, the conditions specified in 

§ 25.963(d)(1) through (d)(5). Therefore, 

to meet the introductory requirement in 

§ 25.963(d), every practicable 

consideration should be made to ensure 

protection of fuel tanks in more severe 

crash conditions, especially tanks 

located in the fuselage below the main 

cabin floor. 

The fuel tank pressure loads specified 

in § 25.963(d) vary depending on 

whether the fuel tank is within or 

outside the pressure boundary. For 

certification of unpressurized airplanes, 

all fuel tanks should be considered to be 

‘‘within’’ the fuselage pressure 

boundary, unless a fire resistant barrier 

exists between the fuel tank and the 

occupied compartments of the airplane. 

Finally, the FAA notes that, for future 

rulemaking, we plan to consider specific 

crashworthiness requirements that 

would exceed the quantitative criteria 

specified in §§ 25.561, 25.721, and 

25.963. Also, the FAA has recently 

applied special conditions on certain 

airplanes that require a crashworthiness 

evaluation at descent rates up to 30 feet 

per second. 


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G. Section 25.994, Fuel System 

Components 

To date, § 25.994 has required that 

fuel system components in an engine 

nacelle or in the fuselage be protected 

from damage that could result in 

spillage of enough fuel to constitute a 

fire hazard as a result of a wheels-up 

landing on a paved runway. We 

proposed to revise § 25.994 to specify 

that the wheels-up landing conditions 

that must be considered are those 

prescribed in § 25.721(b). 

A commenter proposed two changes 

to what the FAA proposed: (1) Add a 

reference to § 25.721(c), and (2) change 

the order in which the nacelles and the 

fuselage are referenced, based on the 

order the fuselage and nacelle are 

addressed in § 25.721. We do not agree 

with the proposed changes. Adding a 

reference to § 25.721(c) would not be 

correct because wheels-up landing 

conditions are only listed in § 25.721(b). 

Since § 25.721(c) is not referenced in 

§ 25.994, and since § 25.721(b) does not 

refer to the fuselage or nacelles, there is 

no reason to change the order in which 

the fuselage and nacelles are specified 

in § 25.994. 

H. Advisory Material 

On March 13, 2013, the FAA 

published and solicited public 

comments on three proposed ACs that 

describe acceptable means for showing 

compliance with the proposed 

regulations in the NPRM. The comment 

period for the proposed ACs closed on 

June 14, 2013. Concurrently with this 

final rule, the FAA is issuing the 

following new ACs to provide guidance 

material for the regulations adopted by 

this amendment: 

• AC 25–30, ‘‘Fuel Tank Strength in 

Emergency Landing Conditions.’’ (AC 

25–30 would provide guidance for the 

fuel tank structural integrity 

requirements of §§ 25.561, 25.721, and 

25.963.) 

• AC 25.307–1, ‘‘Proof of Structure.’’ 

• AC 25.621–1, ‘‘Casting Factors.’’ 

IV. Regulatory Notices and Analyses 

A. Regulatory Evaluation 

Changes to Federal regulations must 

undergo several economic analyses. 

First, Executive Order 12866 and 

Executive Order 13563 direct 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, the 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. 

Department of Transportation Order 

DOT 2100.5 prescribes policies and 

procedures for simplification, analysis, 

and review of regulations. If the 

expected cost impact is so minimal that 

a proposed or final rule does not 

warrant a full evaluation, this order 

permits that a statement to that effect 

and the basis for it be included in the 

preamble if a full regulatory evaluation 

of the cost and benefits is not prepared. 

Such a determination has been made for 

this final rule. The reasoning for this 

determination follows. 

The FAA is amending certain 

airworthiness standards for transport 

category airplanes. Adopting this final 

rule would eliminate regulatory 

differences between the airworthiness 

standards of the FAA and the EASA. 

This final rule does not add new 

requirements as U.S. manufacturers 

currently meet EASA requirements. 

Meeting two sets of certification 

requirements imposes greater costs for 

developing new transport category 

airplanes with little to no increase in 

safety. In the interest of fostering 

international trade, lowering the cost of 

manufacturing new transport category 

airplanes, and making the certification 

process more efficient, the FAA, EASA, 

and several industry working groups 

came together to create, to the maximum 

extent possible, a single set of 

certification requirements that would be 

accepted in both the United States and 

Europe. Therefore, as a result of these 

harmonization efforts, the FAA is 

amending the airworthiness regulations 

described in section I of this final rule, 

‘‘Overview of the Final Rule.’’ This 

action harmonizes part 25 requirements 

with the corresponding requirements in 

EASA CS–25 Book 1. 

In order to sell their aircraft in 

Europe, all manufacturers of transport 

category airplanes, certificated under 

part 25 must be in compliance with the 

EASA certification requirements in CS– 

25 Book 1. Since future certificated 

transport airplanes are expected to meet 

CS–25 Book 1, and this rule simply 

adopts the same EASA requirements, 

manufacturers will incur minimal or no 

additional cost resulting from this final 

rule. Therefore, the FAA estimates that 

there are no additional costs associated 

with this final rule. 

In fact, manufacturers could receive 

cost savings because they will not have 

to build and certificate transport 

category airplanes to two different 

authorities’ certification specifications 

and rules. Further, harmonization of 

these airworthiness standards, 

specifically § 25.621 may benefit 

manufacturers by providing another 

option in developing aircraft structures. 

The final rule permits use of a lower 

casting factor for critical castings, 

provided that tight controls are 

established for the casting process, 

inspection, and testing, which lead to 

cost savings in terms of aircraft weight. 

These additional controls are expected 

to at least maintain an equivalent level 

of safety as provided by existing 

regulations for casting factors. 

The FAA has not attempted to 

quantify the cost savings that may 

accrue from this final rule, beyond 

noting that, while they may be minimal, 

they contribute overall to a potential 

harmonization savings. The agency 

concludes that because the compliance 

cost for this final rule is minimal and 

there may be harmonization cost 

savings, further analysis is not required. 

During the public comment period, 

the Agency received 16 comments from 

5 commenters. There were no comments 

regarding costs to this final rule; 

however, one commenter raised concern 

for safety in § 25.621. Details of this 

comment and the FAA’s response can 

be found in the ‘‘General Overview of 

Comments’’ section. These 

harmonization efforts ensure that the 

current level of safety in transport 

category airplanes is maintained while 

encouraging the use of modern casting 

process technology. 

The agency concludes that the 

changes would eliminate regulatory 

differences between the airworthiness 

standards of the FAA and EASA 

resulting in potential cost savings and 

maintaining current levels of safety. The 

FAA has, therefore, determined that this 

final rule is not a ‘‘significant regulatory 

action’’ as defined in section 3(f) of 

Executive Order 12866, and is not 

‘‘significant’’ as defined in DOT’s 

Regulatory Policies and Procedures. 


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B. Regulatory Flexibility Determination 

The Regulatory Flexibility Act of 1980 

(Pub. L. 96–354) (RFA) establishes ‘‘as a 

principle of regulatory issuance that 

agencies shall endeavor, consistent with 

the objectives of the rule and of 

applicable statutes, to fit regulatory and 

informational requirements to the scale 

of the businesses, organizations, and 

governmental jurisdictions subject to 

regulation. To achieve this principle, 

agencies are required to solicit and 

consider flexible regulatory proposals 

and to explain the rationale for their 

actions to assure that such proposals are 

given serious consideration.’’ The RFA 

covers a wide-range of small entities, 

including small businesses, not-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. 

The FAA believes that this final rule 

does not have a significant economic 

impact on a substantial number of small 

entities for the following reasons. The 

net effect of this final rule is minimum 

regulatory cost relief, as the rule would 

adopt EASA requirements that the 

industry already meets. Further, all 

United States transport category aircraft 

manufacturers exceed the Small 

Business Administration small-entity 

criteria of 1,500 employees. The Agency 

received no comments regarding the 

Regulatory Flexibility Act during the 

public comment period. 

If an agency determines that a 

rulemaking will not result in a 

significant economic impact on a 

substantial number of small entities, the 

head of the agency may so certify under 

section 605(b) of the RFA. Therefore, as 

provided in section 605(b), the head of 

the FAA certifies that this rulemaking 

will not result in a significant economic 

impact on a substantial number of small 

entities. 

C. International Trade Impact 

Assessment 

The Trade Agreements Act of 1979 

(Pub. L. 96–39), as amended by the 

Uruguay Round Agreements Act (Pub. 

L. 103–465), prohibits Federal agencies 

from establishing standards or engaging 

in related activities that create 

unnecessary obstacles to the foreign 

commerce of the United States. 

Pursuant to these Acts, the 

establishment of standards is not 

considered an unnecessary obstacle to 

the foreign commerce of the United 

States, so long as the standard has a 

legitimate domestic objective, such the 

protection of safety, and does not 

operate in a manner that excludes 

imports that meet this objective. The 

statute also requires consideration of 

international standards and, where 

appropriate, that they be the basis for 

U.S. standards. The FAA has assessed 

the potential effect of this final rule and 

determined that it is in accord with the 

Trade Agreements Act as the final rule 

uses European standards as the basis for 

United States regulation. 

D. 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 $151 

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. 

E. 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. The 

FAA has determined that there would 

be no new requirement for information 

collection associated with this final 

rule. 

F. International Compatibility and 

Cooperation 

(1) In keeping with U.S. obligations 

under the Convention on International 

Civil Aviation, it is FAA policy to 

conform to International Civil Aviation 

Organization (ICAO) Standards and 

Recommended Practices to the 

maximum extent practicable. The FAA 

has reviewed the corresponding ICAO 

Standards and Recommended Practices 

and has identified no differences with 

these regulations. 

(2) Executive Order (EO) 13609, 

Promoting International Regulatory 

Cooperation, (77 FR 26413, May 4, 

2012) promotes international regulatory 

cooperation to meet shared challenges 

involving health, safety, labor, security, 

environmental, and other issues and 

reduce, eliminate, or prevent 

unnecessary differences in regulatory 

requirements. The FAA has analyzed 

this action under the policy and agency 

responsibilities of Executive Order 

13609, Promoting International 

Regulatory Cooperation. The agency has 

determined that this action would 

eliminate differences between U.S. 

aviation standards and those of other 

civil aviation authorities by creating a 

single set of certification requirements 

for transport category airplanes that 

would be acceptable in both the United 

States and Europe. 

G. Environmental Analysis 

FAA Order 1050.1E identifies FAA 

actions that are categorically excluded 

from preparation of an environmental 

assessment or environmental impact 

statement under the National 

Environmental Policy Act in the 

absence of extraordinary circumstances. 

The FAA has determined this 

rulemaking action qualifies for the 

categorical exclusion identified in 

paragraph 312f of Order 1050.1E and 

involves no extraordinary 

circumstances. 

V. Executive Order Determinations 

A. Executive Order 13132, Federalism 

The FAA has analyzed this final rule 

under the principles and criteria of 

Executive Order 13132, Federalism. The 

agency 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. 

B. Executive Order 13211, Regulations 

That Significantly Affect Energy Supply, 

Distribution, or Use 

The FAA analyzed this final rule 

under Executive Order 13211, Actions 

Concerning Regulations that 

Significantly Affect Energy Supply, 

Distribution, or Use (May 18, 2001). The 

agency has determined that it is not a 

‘‘significant energy action’’ under the 

executive order and it is not likely to 

have a significant adverse effect on the 

supply, distribution, or use of energy. 


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Federal Register / Vol. 79, No. 191 / Thursday, October 2, 2014 / Rules and Regulations 59429 

VI. How To Obtain Additional 

Information 

A. Rulemaking Documents 

An electronic copy of a rulemaking 

document may be obtained by using the 

Internet— 

1. Search the Federal eRulemaking 

Portal (http://www.regulations.gov), 

2. Visit the FAA’s Regulations and 

Policies Web page at http:// 

www.faa.gov/regulations_policies/, or 

3. Access the Government Printing 

Office’s Web page at http:// 

www.gpo.gov/fdsys/. 

Copies may also be obtained by 

sending a request (identified by notice, 

amendment, or docket number of this 

rulemaking) to the Federal Aviation 

Administration, Office of Rulemaking, 

ARM–1, 800 Independence Avenue 

SW., Washington, DC 20591; or by 

calling (202) 267–9680. 

B. Comments Submitted to the Docket 

Comments received may be viewed by 

going to http://www.regulations.gov and 

following the online instructions to 

search the docket number for this 

action. Anyone is able to search the 

electronic form of all comments 

received into any of the FAA’s 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.). 

C. Small Business Regulatory 

Enforcement Fairness Act 

The Small Business Regulatory 

Enforcement Fairness Act (SBREFA) of 

1996 requires the FAA to comply with 

small entity requests for information or 

advice about compliance with statutes 

and regulations within its jurisdiction. 

A small entity with questions regarding 

this document, may contact its local 

FAA official, or the person listed under 

the FOR FURTHER INFORMATION CONTACT

heading at the beginning of the 

preamble. To find out more about 

SBREFA on the Internet, visit http:// 

www.faa.gov/regulations_policies/

rulemaking/sbre_act/. 

List of Subjects in 14 CFR Part 25 

Aircraft, Aviation safety, Reporting 

and recordkeeping requirements. 

The Amendment 

In consideration of the foregoing, the 

Federal Aviation Administration 

amends chapter I 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 § 25.307 by revising 

paragraph (a) to read as follows: 

§ 25.307 Proof of structure. 

(a) Compliance with the strength and 

deformation requirements of this 

subpart must be shown for each critical 

loading condition. Structural analysis 

may be used only if the structure 

conforms to that for which experience 

has shown this method to be reliable. In 

other cases, substantiating tests must be 

made to load levels that are sufficient to 

verify structural behavior up to loads 

specified in § 25.305. 

* * * * * 

■ 3. Amend § 25.621 by revising 

paragraphs (a), (c), and (d) to read as 

follows: 

§ 25.621 Casting factors. 

(a) General. For castings used in 

structural applications, the factors, tests, 

and inspections specified in paragraphs 

(b) through (d) of this section must be 

applied in addition to those necessary to 

establish foundry quality control. The 

inspections must meet approved 

specifications. Paragraphs (c) and (d) of 

this section apply to any structural 

castings, except castings that are 

pressure tested as parts of hydraulic or 

other fluid systems and do not support 

structural loads. 

* * * * * 

(c) Critical castings. Each casting 

whose failure could preclude continued 

safe flight and landing of the airplane or 

could result in serious injury to 

occupants is a critical casting. Each 

critical casting must have a factor 

associated with it for showing 

compliance with strength and 

deformation requirements of § 25.305, 

and must comply with the following 

criteria associated with that factor: 

(1) A casting factor of 1.0 or greater 

may be used, provided that— 

(i) It is demonstrated, in the form of 

process qualification, proof of product, 

and process monitoring that, for each 

casting design and part number, the 

castings produced by each foundry and 

process combination have coefficients of 

variation of the material properties that 

are equivalent to those of wrought alloy 

products of similar composition. 

Process monitoring must include testing 

of coupons cut from the prolongations 

of each casting (or each set of castings, 

if produced from a single pour into a 

single mold in a runner system) and, on 

a sampling basis, coupons cut from 

critical areas of production castings. The 

acceptance criteria for the process 

monitoring inspections and tests must 

be established and included in the 

process specifications to ensure the 

properties of the production castings are 

controlled to within levels used in 

design. 

(ii) Each casting receives: 

(A) Inspection of 100 percent of its 

surface, using visual inspection and 

liquid penetrant or equivalent 

inspection methods; and 

(B) Inspection of structurally 

significant internal areas and areas 

where defects are likely to occur, using 

radiographic or equivalent inspection 

methods. 

(iii) One casting undergoes a static 

test and is shown to meet the strength 

and deformation requirements of 

§ 25.305(a) and (b). 

(2) A casting factor of 1.25 or greater 

may be used, provided that— 

(i) Each casting receives: 

(A) Inspection of 100 percent of its 

surface, using visual inspection and 

liquid penetrant or equivalent 

inspection methods; and 

(B) Inspection of structurally 

significant internal areas and areas 

where defects are likely to occur, using 

radiographic or equivalent inspection 

methods. 

(ii) Three castings undergo static tests 

and are shown to meet: 

(A) The strength requirements of 

§ 25.305(b) at an ultimate load 

corresponding to a casting factor of 1.25; 

and 

(B) The deformation requirements of 

§ 25.305(a) at a load of 1.15 times the 

limit load. 

(3) A casting factor of 1.50 or greater 

may be used, provided that— 

(i) Each casting receives: 

(A) Inspection of 100 percent of its 

surface, using visual inspection and 

liquid penetrant or equivalent 

inspection methods; and 

(B) Inspection of structurally 

significant internal areas and areas 

where defects are likely to occur, using 

radiographic or equivalent inspection 

methods. 

(ii) One casting undergoes a static test 

and is shown to meet: 

(A) The strength requirements of 

§ 25.305(b) at an ultimate load 

corresponding to a casting factor of 1.50; 

and 

(B) The deformation requirements of 

§ 25.305(a) at a load of 1.15 times the 

limit load. 

(d) Non-critical castings. For each 

casting other than critical castings, as 


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59430 Federal Register / Vol. 79, No. 191 / Thursday, October 2, 2014 / Rules and Regulations 

specified in paragraph (c) of this 

section, the following apply: 

(1) A casting factor of 1.0 or greater 

may be used, provided that the 

requirements of (c)(1) of this section are 

met, or all of the following conditions 

are met: 

(i) Castings are manufactured to 

approved specifications that specify the 

minimum mechanical properties of the 

material in the casting and provides for 

demonstration of these properties by 

testing of coupons cut from the castings 

on a sampling basis. 

(ii) Each casting receives: 

(A) Inspection of 100 percent of its 

surface, using visual inspection and 

liquid penetrant or equivalent 

inspection methods; and 

(B) Inspection of structurally 

significant internal areas and areas 

where defects are likely to occur, using 

radiographic or equivalent inspection 

methods. 

(iii) Three sample castings undergo 

static tests and are shown to meet the 

strength and deformation requirements 

of § 25.305(a) and (b). 

(2) A casting factor of 1.25 or greater 

may be used, provided that each casting 

receives: 

(i) Inspection of 100 percent of its 

surface, using visual inspection and 

liquid penetrant or equivalent 

inspection methods; and 

(ii) Inspection of structurally 

significant internal areas and areas 

where defects are likely to occur, using 

radiographic or equivalent inspection 

methods. 

(3) A casting factor of 1.5 or greater 

may be used, provided that each casting 

receives inspection of 100 percent of its 

surface using visual inspection and 

liquid penetrant or equivalent 

inspection methods. 

(4) A casting factor of 2.0 or greater 

may be used, provided that each casting 

receives inspection of 100 percent of its 

surface using visual inspection 

methods. 

(5) The number of castings per 

production batch to be inspected by 

non-visual methods in accordance with 

paragraphs (d)(2) and (3) of this section 

may be reduced when an approved 

quality control procedure is established. 

■ 4. Revise § 25.683 to read as follows: 

§ 25.683 Operation tests. 

(a) It must be shown by operation 

tests that when portions of the control 

system subject to pilot effort loads are 

loaded to 80 percent of the limit load 

specified for the system and the 

powered portions of the control system 

are loaded to the maximum load 

expected in normal operation, the 

system is free from— 

(1) Jamming; 

(2) Excessive friction; and 

(3) Excessive deflection. 

(b) It must be shown by analysis and, 

where necessary, by tests, that in the 

presence of deflections of the airplane 

structure due to the separate application 

of pitch, roll, and yaw limit maneuver 

loads, the control system, when loaded 

to obtain these limit loads and operated 

within its operational range of 

deflections, can be exercised about all 

control axes and remain free from— 

(1) Jamming; 

(2) Excessive friction; 

(3) Disconnection; and 

(4) Any form of permanent damage. 

(c) It must be shown that under 

vibration loads in the normal flight and 

ground operating conditions, no hazard 

can result from interference or contact 

with adjacent elements. 

■ 5. Revise § 25.721 to read as follows: 

§ 25.721 General. 

(a) The landing gear system must be 

designed so that when it fails due to 

overloads during takeoff and landing, 

the failure mode is not likely to cause 

spillage of enough fuel to constitute a 

fire hazard. The overloads must be 

assumed to act in the upward and aft 

directions in combination with side 

loads acting inboard and outboard. In 

the absence of a more rational analysis, 

the side loads must be assumed to be up 

to 20 percent of the vertical load or 20 

percent of the drag load, whichever is 

greater. 

(b) The airplane must be designed to 

avoid any rupture leading to the spillage 

of enough fuel to constitute a fire hazard 

as a result of a wheels-up landing on a 

paved runway, under the following 

minor crash landing conditions: 

(1) Impact at 5 feet-per-second vertical 

velocity, with the airplane under 

control, at Maximum Design Landing 

Weight— 

(i) With the landing gear fully 

retracted; and 

(ii) With any one or more landing gear 

legs not extended. 

(2) Sliding on the ground, with— 

(i) The landing gear fully retracted 

and with up to a 20° yaw angle; and 

(ii) Any one or more landing gear legs 

not extended and with 0° yaw angle. 

(c) For configurations where the 

engine nacelle is likely to come into 

contact with the ground, the engine 

pylon or engine mounting must be 

designed so that when it fails due to 

overloads (assuming the overloads to act 

predominantly in the upward direction 

and separately, predominantly in the aft 

direction), the failure mode is not likely 

to cause the spillage of enough fuel to 

constitute a fire hazard. 

■ 6. Amend § 25.787 by revising 

paragraph (a) to read as follows: 

§ 25.787 Stowage compartments. 

(a) Each compartment for the stowage 

of cargo, baggage, carry-on articles, and 

equipment (such as life rafts), and any 

other stowage compartment, must be 

designed for its placarded maximum 

weight of contents and for the critical 

load distribution at the appropriate 

maximum load factors corresponding to 

the specified flight and ground load 

conditions, and to those emergency 

landing conditions of § 25.561(b)(3) for 

which the breaking loose of the contents 

of such compartments in the specified 

direction could— 

(1) Cause direct injury to occupants; 

(2) Penetrate fuel tanks or lines or 

cause fire or explosion hazard by 

damage to adjacent systems; or 

(3) Nullify any of the escape facilities 

provided for use after an emergency 

landing. 

If the airplane has a passenger-seating 

configuration, excluding pilot seats, of 

10 seats or more, each stowage 

compartment in the passenger cabin, 

except for under seat and overhead 

compartments for passenger 

convenience, must be completely 

enclosed. 

* * * * * 

■ 7. Amend § 25.963 by revising 

paragraph (d) to read as follows: 

§ 25.963 Fuel tanks: general. 

* * * * * 

(d) Fuel tanks must, so far as it is 

practicable, be designed, located, and 

installed so that no fuel is released in or 

near the fuselage, or near the engines, in 

quantities that would constitute a fire 

hazard in otherwise survivable 

emergency landing conditions, and— 

(1) Fuel tanks must be able to resist 

rupture and retain fuel under ultimate 

hydrostatic design conditions in which 

the pressure P within the tank varies in 

accordance with the formula: 

P = KrgL 

Where— 

P = fuel pressure at each point within the 

tank 

r = typical fuel density 

g = acceleration due to gravity 

L = a reference distance between the point of 

pressure and the tank farthest boundary 

in the direction of loading 

K = 4.5 for the forward loading condition for 

those parts of fuel tanks outside the 

fuselage pressure boundary 

K = 9 for the forward loading condition for 

those parts of fuel tanks within the 

fuselage pressure boundary, or that form 

part of the fuselage pressure boundary 

K = 1.5 for the aft loading condition 

K = 3.0 for the inboard and outboard loading 

conditions for those parts of fuel tanks 


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Federal Register / Vol. 79, No. 191 / Thursday, October 2, 2014 / Rules and Regulations 59431 

within the fuselage pressure boundary, 

or that form part of the fuselage pressure 

boundary 

K = 1.5 for the inboard and outboard loading 

conditions for those parts of fuel tanks 

outside the fuselage pressure boundary 

K = 6 for the downward loading condition 

K = 3 for the upward loading condition 

(2) For those parts of wing fuel tanks 

near the fuselage or near the engines, 

the greater of the fuel pressures 

resulting from paragraphs (d)(2)(i) or 

(d)(2)(ii) of this section must be used: 

(i) The fuel pressures resulting from 

paragraph (d)(1) of this section, and 

(ii) The lesser of the two following 

conditions: 

(A) Fuel pressures resulting from the 

accelerations specified in § 25.561(b)(3) 

considering the fuel tank full of fuel at 

maximum fuel density. Fuel pressures 

based on the 9.0g forward acceleration 

may be calculated using the fuel static 

head equal to the streamwise local 

chord of the tank. For inboard and 

outboard conditions, an acceleration of 

1.5g may be used in lieu of 3.0g as 

specified in § 25.561(b)(3). 

(B) Fuel pressures resulting from the 

accelerations as specified in 

§ 25.561(b)(3) considering a fuel volume 

beyond 85 percent of the maximum 

permissible volume in each tank using 

the static head associated with the 85 

percent fuel level. A typical density of 

the appropriate fuel may be used. For 

inboard and outboard conditions, an 

acceleration of 1.5g may be used in lieu 

of 3.0g as specified in § 25.561(b)(3). 

(3) Fuel tank internal barriers and 

baffles may be considered as solid 

boundaries if shown to be effective in 

limiting fuel flow. 

(4) For each fuel tank and 

surrounding airframe structure, the 

effects of crushing and scraping actions 

with the ground must not cause the 

spillage of enough fuel, or generate 

temperatures that would constitute a 

fire hazard under the conditions 

specified in § 25.721(b). 

(5) Fuel tank installations must be 

such that the tanks will not rupture as 

a result of the landing gear or an engine 

pylon or engine mount tearing away as 

specified in § 25.721(a) and (c). 

* * * * * 

■ 8. Revise § 25.994 to read as follows: 

§ 25.994 Fuel system components. 

Fuel system components in an engine 

nacelle or in the fuselage must be 

protected from damage that could result 

in spillage of enough fuel to constitute 

a fire hazard as a result of a wheels-up 

landing on a paved runway under each 

of the conditions prescribed in 

§ 25.721(b). 

Issued under authority provided by 49 

U.S.C. 106(f), 44701(a), and 44703 in 

Washington, DC, on September 24, 2014. 

Michael P. Huerta, 

Administrator. 

[FR Doc. 2014–23373 Filed 10–1–14; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 25 

[Docket No. FAA–2014–0366; Special 

Conditions No. 25–564–SC] 

Special Conditions: Embraer S.A.; 

Model EMB–550 Airplane; Flight 

Envelope Protection: High Incidence 

Protection System 

Correction 

In rule document 2014–20893 

appearing on pages 52165 through 

52169 in the issue of Wednesday, 

September 3, 2014, make the following 

corrections: 

1. On page 52169, in the first column, 

the 27th line from the bottom should 

read: ‘‘In lieu of § 25.107(c) and (g) we 

propose the following requirements, 

with additional sections (c’) and (g’):’’ 

2. On page 52169, in the first column, 

the 11th line from the bottom should 

read: ‘‘(c’) In icing conditions with the 

‘‘takeoff ice’’ accretion defined in part 

25, appendix C, V2 may not be less 

than—’’ 

3. On page 52169, in the second 

column, the eighth line from the top 

should read: ‘‘(g’) In icing conditions 

with the ‘‘final takeoff ice’’ accretion 

defined in part 25, appendix C, VFTO, 

may not be less than—’’ 

[FR Doc. C1–2014–20893 Filed 10–1–14; 8:45 am] 

BILLING CODE 1505–01–P 

DEPARTMENT OF HOMELAND 

SECURITY 

Coast Guard 

33 CFR Part 117 

[Docket No. USCG–2014–0848] 

Drawbridge Operation Regulation; 

Sacramento River, Rio Vista, CA 

AGENCY: Coast Guard, DHS. 

ACTION: Notice of deviation from 

drawbridge regulation. 

SUMMARY: The Coast Guard has issued a 

temporary deviation from the operating 

schedule that governs the Rio Vista 

Drawbridge across Sacramento River, 

mile 12.8, at Rio Vista, CA. The 

deviation is necessary to allow the 

bridge owner to make necessary bridge 

maintenance repairs. This deviation 

allows the bridge to open on four hours 

advance notice during the deviation 

period. 

DATES: This deviation is effective 

without actual notice from October 2, 

2014 through 6 a.m. on October 17, 

2014. For the purposes of enforcement, 

actual notice will be used from 9 p.m. 

on September 22, 2014, until October 2, 

2014. 

ADDRESSES: The docket for this 

deviation, [USCG–2014–0848], is 

available at http://www.regulations.gov. 

Type the docket number in the 

‘‘SEARCH’’ box and click ‘‘SEARCH.’’ 

Click on Open Docket Folder on the line 

associated with this deviation. You may 

also visit the Docket Management 

Facility in Room W12–140 on the 

ground floor of the Department of 

Transportation West Building, 1200 

New Jersey Avenue SE., Washington, 

DC 20590, between 9 a.m. and 5 p.m., 

Monday through Friday, except Federal 

holidays. 

FOR FURTHER INFORMATION CONTACT: If 

you have questions on this temporary 

deviation, call or email David H. 

Sulouff, Chief, Bridge Section, Eleventh 

Coast Guard District; telephone 510– 

437–3516, email David.H.Sulouff@

uscg.mil. If you have questions on 

viewing the docket, call Cheryl Collins, 

Program Manager, Docket Operations, 

telephone 202–366–9826. 

SUPPLEMENTARY INFORMATION: The 

California Department of Transportation 

has requested a temporary change to the 

operation of the Rio Vista Drawbridge, 

mile 12.8, over Sacramento River, at Rio 

Vista, CA. The drawbridge navigation 

span provides 18 feet vertical clearance 

above Mean High Water in the closedto-navigation position. In accordance 

with 33 CFR 117.5, the draw opens on 

signal. Navigation on the waterway is 

commercial, search and rescue, law 

enforcement, and recreational. 

A four-hour advance notice for 

openings is required from 9 p.m. to 6 

a.m. daily, from September 22, 2014 to 

October 17, 2014, to allow the bridge 

owner to repair the concrete vertical lift 

span deck. This temporary deviation has 

been coordinated with the waterway 

users. No objections to the temporary 

deviation were raised. 

Vessels able to pass through the 

bridge in the closed position may do so 

at any time. The bridge will be able to 

open for emergencies with four hour 

advance notice. No alternative route is 

available for navigation. The Coast 

Guard will inform waterway users of 


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