Federal Register / Vol. 76, No. 37 / Thursday, February 24, 2011 / Rules and Regulations 10213 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 25 

[Docket No. NM449; Notice No. 25–420–SC] 

Special Conditions: Embraer Model 

EMB–135BJ (Legacy 650) Airplanes, 

Limit Engine Torque Loads for Sudden 

Engine Stoppage 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Final special conditions; request 

for comments. 

SUMMARY: These special conditions are 

issued for the Embraer Model EMB– 

135BJ (Legacy 650) airplanes, modified 

in accordance with design-change 

application (DCA) 0145–000–00020– 

2008/FAA (the most current FAAapproved revision; hereafter referred to 

as ‘‘the DCA’’). This Model EMB–135BJ 

airplane, as modified by the DCA, is 

commonly referred to as the Legacy 650 

airplane. It will have a novel or unusual 

design feature associated with engine 

size and the potential torque load 

imposed by sudden engine-stoppage 

conditions. The applicable 

airworthiness regulations do not contain 

adequate or appropriate safety standards 

for this design feature. These special 

conditions contain the additional safety 

standards that the Administrator 

considers necessary to establish a level 

of safety equivalent to that established 

by the existing airworthiness standards. 

DATES: The effective date of these 

special conditions is February 17, 2011. 

We must receive your comments by 

April 11, 2011. 

ADDRESSES: You must mail two copies 

of your comments to: Federal Aviation 

Administration, Transport Airplane 

Directorate, Attn: Rules Docket (ANM– 

113), Docket No. NM449, 1601 Lind 

Avenue, SW., Renton, Washington 

98057–3356. You may deliver two 

copies to the Transport Airplane 

Directorate at the above address. You 

must mark your comments: Docket No. 

NM449. You can inspect comments in 

the Rules Docket weekdays, except 

Federal holidays, between 7:30 a.m. and 

4 p.m. 

FOR FURTHER INFORMATION CONTACT: Carl 

Niedermeyer, FAA Airframe Branch, 

ANM–115, Transport Airplane 

Directorate, Aircraft Certification 

Service, 1601 Lind Avenue, SW., 

Renton, Washington 98057–3356; 

telephone (425) 227–2279; facsimile 

(425) 227–1149; e-mail 

carl.niedermeyer@faa.gov. 

SUPPLEMENTARY INFORMATION: The FAA 

has determined that notice of, and 

opportunity for prior public comment 

on, these special conditions are 

impracticable because these procedures 

would significantly delay issuance of 

the design approval and thus delivery of 

the affected aircraft. In addition, the 

substance of these special conditions 

has been subject to the public-comment 

process in several prior instances with 

no substantive comments received. The 

FAA therefore finds that good cause 

exists for making these special 

conditions effective upon issuance. 

Comments Invited 

We invite interested people to take 

part in this rulemaking by sending 

written comments, data, or views. The 

most helpful comments reference a 

specific portion of the special 

conditions, explain the reason for any 

recommended change, and include 

supporting data. We ask that you send 

us two copies of written comments. 

We will file in the docket all 

comments we receive, as well as a 

report summarizing each substantive 

public contact with FAA personnel 

concerning these special conditions. 

You can inspect the docket before and 

after the comment closing date. If you 

wish to review the docket in person, go 

to the address in the ADDRESSES section 

of this preamble between 7:30 a.m. and 

4 p.m., Monday through Friday, except 

Federal holidays. 

We will consider all comments we 

receive on or before the closing date for 

comments. We will consider comments 

filed late if it is possible to do so 

without incurring expense or delay. We 

may change these special conditions 

based on the comments we receive. 

If you want us to acknowledge receipt 

of your comments on these special 

conditions, include with your 

comments a self-addressed, stamped 

postcard on which you have written the 

docket number. We will stamp the date 

on the postcard and mail it back to you. 

Background 

On September 19, 2008, Embraer 

applied for an amendment to U.S. type 

certificate (TC) T00011AT to include the 

new certification basis of Model EMB– 

135BJ (Legacy 650), modified according 

to major level 1 design change 

documented in DCA 0145–000–00020– 

2008/FAA Revision original. This 

airplane is a derivative of the Model 

EMB–135BJ (Legacy 600) airplane, 

which is approved under the same TC. 

The Model EMB–135BJ (Legacy 650) 

airplane, modified according to the 

DCA, is powered by two Rolls Royce 

Allison engines, model AE3007A2. The 

airplane has an interior seating 

arrangement similar to the baseline 

configuration Model EMB–135BJ 

(Legacy 600) airplane, with increased 

maximum takeoff weight (MTOW) of 

24,300 kg. It is intended for long-range 

operations with enhanced performance, 

and has additional fuel capacity over 

the Model EMB–135BJ (Legacy 600) 

baseline configuration. 

Type Certification Basis 

Under the provisions of Title 14, Code 

of Federal Regulations (14 CFR), 21.17, 

Embraer must show that the Model 

EMB–135BJ (Legacy 650) airplane meets 

the applicable provisions of the 

regulations incorporated by reference in 

TC T00011AT or the applicable 

regulations in effect on the date of 

application for the change to the TC 

data sheet. The regulations incorporated 

by reference in the type certificate are 

commonly referred to as the ‘‘original 

type-certification basis.’’ The regulations 

incorporated by reference in TC 

T00011AT are 14 CFR part 25 effective 

February 1, 1965, including 

Amendments 25–1 through 25–85, and 

25–86 (applicable for § 25.1517), 25–88, 

25–90, 25–91 (applicable for §§ 25.331, 

25.335(b)(2), 25.351, 25.363, 25.371, 

25.415, 25.491, 25.499 and 25.561), 

25–93, 25–94 (applicable for § 25.807), 

25–96 (applicable for § 25.571(e)(1)), 

25–97, and 25–98, with certain 

exceptions that are not relevant to this 

special condition. 

In addition, if the regulations 

incorporated by reference do not 

provide adequate standards with respect 

to the change, the applicant must 

comply with certain regulations in effect 

on the date of application for the 

change. The FAA has determined that 

the Model EMB–135BJ (Legacy 650) 

airplane must be shown to comply with 

the airworthiness standards of part 25, 

including Amendments 25–1 through 

25–124, for components, areas, 

appliances, and systems affected by the 

type design change presented in the 

DCA. 

If the Administrator finds that the 

applicable airworthiness regulations 

(i.e., 14 CFR part 25) do not contain 

adequate or appropriate safety standards 

for the Model EMB–135BJ (Legacy 650) 

airplane because of a novel or unusual 

design feature, special conditions are 

prescribed under the provisions of 14 

CFR 21.16. 

In addition to the applicable 

airworthiness regulations and special 

conditions, this Model EMB–135BJ 

(Legacy 650) airplane must comply with 

the fuel-vent and exhaust-emission 

requirements of 14 CFR part 34 and the 


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10214 Federal Register / Vol. 76, No. 37 / Thursday, February 24, 2011 / Rules and Regulations 

noise certification requirements of 14 

CFR part 36. 

Special conditions, as defined in 14 

CFR 11.19, are issued according to 

§ 11.38 and become part of the typecertification basis according to 14 CFR 

21.101(b)(2). 

Special conditions are initially 

applicable to the model for which they 

are issued. Should the type certificate 

for that model be amended later to 

include any other model that 

incorporates the same novel or unusual 

design feature, or should any other 

model already included on the same 

type certificate be modified to 

incorporate the same novel or unusual 

design feature, the special conditions 

would also apply to the other model 

under the provisions of 14 CFR 

21.101(a)(1). 

Novel or Unusual Design Features 

The Model EMB–135BJ (Legacy 650) 

airplane will incorporate novel or 

unusual design features involving 

engine size and the potential torque 

load imposed by sudden-enginestoppage conditions. 

Discussion 

The limit engine-torque load imposed 

by sudden engine stoppage, due to 

malfunction or structural failure (such 

as compressor jamming), has been a 

specific requirement for transportcategory airplanes since 1957. The size, 

configuration, and failure modes of jet 

engines have changed considerably from 

those envisioned when the engine 

seizure requirement of § 25.361(b) was 

first adopted. Current engines are much 

larger and are now designed with large 

bypass fans capable of producing much 

larger torque loads if they become 

jammed. It is evident from service 

history that the frequency of occurrence 

of the most severe sudden-enginestoppage events is rare. 

Relative to the engine configurations 

that existed when the rule was 

developed in 1957, the present 

generation of engines are sufficiently 

different and novel to justify issuance of 

special conditions to establish 

appropriate design standards. The latest 

generation of jet engines is capable of 

producing, during failure, transient 

loads that are significantly higher and 

more complex than the generation of 

engines that were present when the 

existing standard was developed. 

Therefore, the FAA has determined that 

special conditions are needed for the 

Model EMB–135BJ (Legacy 650) 

airplanes. 

To maintain the level of safety 

intended in § 25.361(b), a more 

comprehensive criteria is needed for the 

new generation of high-bypass engines. 

These special conditions would 

distinguish between the more-common 

seizure events and those less-common 

seizure events resulting from structural 

failures. For those less-common but 

severe seizure events, these criteria 

could allow some deformation in the 

engine-supporting structure (ultimate 

load design) in order to absorb the 

higher energy associated with the highbypass engines, while at the same time 

protecting the adjacent primary 

structure in the wing and fuselage by 

providing a higher safety factor. The 

criteria for the more-severe events 

would no longer be a pure static torqueload condition, but would account for 

the full spectrum of transient dynamic 

loads developed from the engine-failure 

condition. 

Applicability 

As discussed above, these special 

conditions are applicable to the Model 

EMB–135BJ (Legacy 650) airplanes. 

Should Embraer apply at a later date for 

a change to the type design of a certified 

airplane without new model designation 

on Type Certificate No. T00011AT to 

incorporate the same novel or unusual 

design feature, the special conditions 

would apply to that model as well 

under the provisions of § 21.101(a)(1). 

Certification of the Model EMB–135BJ 

(Legacy 650) airplane is currently 

scheduled for February 18, 2011. The 

substance of these special conditions 

has been subject to the notice and 

public-comment procedure in several 

prior instances. Therefore, because a 

delay would significantly affect the 

applicant’s both installation of the 

system and certification of the airplane, 

these special conditions are effective 

upon issuance. 

Conclusion 

This action affects only certain novel 

or unusual design features on Model 

EMB–135BJ airplanes. It is not a rule of 

general applicability and it affects only 

the applicant who applied to the FAA 

for approval of these features on the 

airplane. 

Under standard practice, the effective 

date of final special conditions would 

be 30 days after the date of publication 

in the Federal Register; however, as the 

certification date for the Embraer Model 

EMB–135BJ (Legacy 650) airplane is 

imminent, the FAA finds that good 

cause exists to make these special 

conditions effective upon issuance. 

List of Subjects in 14 CFR Part 25 

Aircraft, Aviation safety, Reporting 

and recordkeeping requirements. 

The authority citation for these 

special conditions is as follows: 

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

44702, 44704. 

The Special Conditions 

Accordingly, pursuant to the 

authority delegated to me by the 

Administrator, the following special 

conditions are issued as part of the type 

certification basis for the Embraer 

Model EMB–135BJ (Legacy 650) 

airplanes. 

1. For turbine engine installations, the 

engine mounts, pylons and adjacent 

supporting airframe structure must be 

designed to withstand 1g level flight 

loads acting simultaneously with the 

maximum limit torque loads imposed 

by each of the following: 

a. Sudden engine deceleration due to 

a malfunction, which could result in a 

temporary loss of power or thrust; and 

b. The maximum acceleration of the 

engine. 

2. For auxiliary-power-unit 

installations, the power-unit mounts 

and adjacent supporting airframe 

structure must be designed to withstand 

1g level flight loads acting 

simultaneously with the maximum limit 

torque loads imposed by each of the 

following: 

a. Sudden auxiliary-power-unit 

deceleration due to malfunction or 

structural failure; and 

b. The maximum acceleration of the 

power unit. 

3. For engine supporting structure, an 

ultimate loading condition must be 

considered that combines 1g flight loads 

with the transient dynamic loads 

resulting from: 

a. The loss of any fan, compressor, or 

turbine blade; and 

b. Separately, where applicable to a 

specific engine design, any other engine 

structural failure that results in higher 

loads. 

4. The ultimate loads developed from 

these conditions are to be multiplied by 

a factor of 1.0 when applied to engine 

mounts and pylons and multiplied by a 

factor of 1.25 when applied to adjacent 

supporting airframe structure. 

5. Any permanent deformation that 

results from the conditions specified in 

Special Condition number 3 must not 

prevent continued safe flight and 

landing. 

Issued in Renton, Washington, on February 

17, 2011. 

Ali Bahrami, 

Manager, Transport Airplane Directorate, 

Aircraft Certification Service. 

[FR Doc. 2011–4072 Filed 2–23–11; 8:45 am] 

BILLING CODE 4910–13–P 


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