Document ID: FAA-2007-27229-0006
Agency: faa
Document Type: Rule
Title: Airworthiness Directives; CFM International, S.A. CFM56-7B Series Turbofan Engines
Posted Date: 2008-02-04T05:00Z

[Federal Register: February 4, 2008 (Volume 73, Number 23)]
[Rules and Regulations]               
[Page 6419-6423]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr04fe08-1]                         

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Rules and Regulations
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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-27229; Directorate Identifier 2007-NE-03-AD; 
Amendment 39-15359; AD 2008-03-09]
RIN 2120-AA64

 
Airworthiness Directives; CFM International, S.A. CFM56-7B Series 
Turbofan Engines

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation.

ACTION: Final rule.

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

SUMMARY: The FAA is adopting a new airworthiness directive (AD) for CFM 
International, S.A. CFM56-7B series turbofan engines. This AD requires 
revising the Airworthiness Limitations Section (ALS) in the Engine Shop 
Manual (ESM) and the air carrier's approved continuous airworthiness 
maintenance program (CAMP) to add mandatory inspections of certain low 
pressure turbine rear frames (TRFs) to the ALS or CAMP. This AD results 
from a refined lifing analysis by the engine manufacturer that shows 
the need to identify an initial threshold for inspecting certain TRFs. 
We are issuing this AD to prevent failure of the TRF from low-cycle 
fatigue cracks. Failure of the TRF could result in engine separation 
from the airplane, which could lead to loss of control of the airplane.

DATES: This AD becomes effective March 10, 2008.

ADDRESSES: The Docket Operations office is located at Docket Management 
Facility, U.S. Department of Transportation, 1200 New Jersey Avenue, 
SE., West Building Ground Floor, Room W12-140, Washington, DC 20590-
0001.

FOR FURTHER INFORMATION CONTACT: Antonio Cancelliere, Aerospace 
Engineer, Engine Certification Office, FAA, Engine and Propeller 
Directorate, 12 New England Executive Park, Burlington, MA 01803; 
telephone (781) 238-7751; fax (781) 238-7199.

SUPPLEMENTARY INFORMATION: The FAA proposed to amend 14 CFR part 39 
with a proposed AD. The proposed AD applies to CFM International, S.A. 
CFM56-7B series turbofan engines. We published the proposed AD in the 
Federal Register on April 23, 2007 (72 FR 20075). That action proposed 
to require revising the ALS in the Engine Shop Manual and the air 
carrier's approved continuous airworthiness maintenance program (CAMP) 
to add mandatory inspections of certain low pressure turbine rear 
frames (TRFs) to the ALS or CAMP.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov
; or in person at the Docket Operations office 

between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The AD docket contains this AD, the regulatory evaluation, 
any comments received, and other information. The street address for 
the Docket Operations office (telephone (800) 647-5527) is provided in 
the ADDRESSES section. Comments will be available in the AD docket 
shortly after receipt.

Comments

    We provided the public the opportunity to participate in the 
development of this AD. We have considered the comments received.

Update Table for Figure 805

    Delta Airlines requests that we change the wording in the table for 
Figure 805 because CFM International updated CFM56-7B Engine Shop 
Manual section 05-21-03, with Temporary Revision 05-0080, dated 
December 5, 2006. We agree and have reworded the table for Figure 805 
to reflect wording used by the original equipment manufacturer (OEM). 
For clarification, we also moved the titles for Figures 806 and 807 to 
the beginning of the figures.

Guidance on Future Revisions

    Delta Airlines also suggests that we provide guidance on making 
future OEM revisions to ESM section 05-21-03 while maintaining 
compliance with the AD. We disagree. The information contained within 
sections (j) and (k) of the AD is adequate. Any future OEM changes to 
the ALS that affect compliance with this AD will require an AD revision 
or supersedure, depending on the specific situation. Airlines should 
make changes to items outside of this specific area and incorporate 
them into their ESM or CAMP per their normal procedures.

Add Part Numbers (P/Ns) to Applicability

    Finally, Delta Airlines requests that we add P/Ns 340-166-251-0, 
340-166-252-0 and 340-166-253-0 to the Applicability section and 
clarify whether these P/Ns will be applicable to the business jet 
application as well as the commercial application. We disagree. The 
intent of this AD is to make operators aware of the life limit/
mandatory inspections recently introduced by CFM International in the 
Airworthiness Limitations Section of the CFM56-7B Engine Shop Manual 
that affect P/Ns that were not previously limited. Ignoring these new 
limitations could create a potentially unsafe condition. The P/Ns 
listed above were subject to a life limit and mandatory inspection when 
first introduced to the ESM, therefore, there is no potential unsafe 
condition. Business jet and commercial engine model applicability of 
the new P/Ns is as listed in the ESM.

Conclusion

    We have carefully reviewed the available data, including the 
comments received, and determined that air safety and the public 
interest require adopting the AD with the changes described previously. 
We have determined that these changes will neither increase the 
economic burden on any operator nor increase the scope of the AD.

Costs of Compliance

    We estimate that this AD will affect 1,228 engines installed on 
airplanes of U.S. registry. While the cost of making the manual change 
is negligible, the resulting inspections must be discussed. Since life 
extensions are possible on condition, the cost of the AD is limited to 
performing TRF inspections. We estimate that it will take about 3.0 
work-hours per engine to perform the actions, including the TRF 
inspections, and that the average labor rate is $80 per work-

[[Page 6420]]

hour. No parts are required. Based on these figures, we estimate the 
total cost of the AD to U.S. operators to be $294,720.

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, Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    We are issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701, ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.

Regulatory Findings

    We have determined that this AD will not have federalism 
implications under Executive Order 13132. This AD will not have a 
substantial direct effect on the States, on the relationship between 
the national government and the States, or on the distribution of power 
and responsibilities among the various levels of government.
    For the reasons discussed above, I certify that this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866;
    (2) Is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and
    (3) Will not have a significant economic impact, positive or 
negative, on a substantial number of small entities under the criteria 
of the Regulatory Flexibility Act.
    We prepared a summary of the costs to comply with this AD and 
placed it in the AD Docket. You may get a copy of this summary at the 
address listed under ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

Adoption of the Amendment

0
Accordingly, under the authority delegated to me by the Administrator, 
the Federal Aviation Administration amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
1. The authority citation for part 39 continues to read as follows:

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

Sec.  39.13  [Amended]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive:

2008-03-09 CFM International, S.A.: Amendment 39-15359. Docket No. 
FAA-2007-27229; Directorate Identifier 2007-NE-03-AD.

Effective Date

    (a) This airworthiness directive (AD) becomes effective March 
10, 2008.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to CFM International, S.A. CFM56-7B18, -
7B20, -7B22, -7B24, -7B26, -7B27, -7B22/B1, -7B24/B1, -7B26/B1, -
7B27/B1, -7B22/B2, -7B26/B2, -7B27/B3 turbofan engines with turbine 
rear frame (TRF), part numbers 340-166-205-0, 340-166-206-0, 340-
166-207-0, 340-166-208-0, 340-166-209-0, and 340-166-210-0, 
installed. These engines are installed on, but not limited to, 
Boeing 737 series airplanes.

Unsafe Condition

    (d) This AD results from a refined lifing analysis by the engine 
manufacturer that shows the need to identify an initial threshold 
for inspecting certain TRFs. We are issuing this AD to prevent 
failure of the TRF from low-cycle fatigue cracks. Failure of the TRF 
could result in engine separation from the airplane, which could 
lead to loss of control of the airplane.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed within 30 days after the effective date of this AD, 
unless the actions have already been done.

Mandatory Inspections

    (f) Within the next 30 days after the effective date of this AD, 
revise the applicable inspection program for the Business Jet and 
Air Carrier engine models by adding the Mandatory Inspection 
Intervals as specified in this AD, and revise the Airworthiness 
Limitations Section (ALS) (chapter 05-21-03) of the CFM56-7B Engine 
Shop Manual, CFMI-TP-SM.10 by adding the following:

TURBINE REAR FRAME WITH TANGENTIAL STRUTS--MANDATORY INSPECTIONS--
LIFE LIMITS

TASK 05-21-03-200-001

1. General
    A. This section contains the FAA and EASA mandatory Eddy Current 
inspection intervals for the turbine rear frame with tangential 
struts. The inspection uses:

--A threshold limit, specified in flight cycles
--Inspection intervals, specified in flight cycles

    B. The threshold limit is the timing of the first required 
inspection. First inspection must be done before that part has 
reached the threshold number of flight cycles.
    C. The inspection intervals specify the timing of inspections to 
be done after the threshold inspection has been reached. Inspections 
are repetitive without any limit.

    2. Mandatory Inspection Intervals for the Critical Areas of the 
Turbine Rear Frame with Tangential Struts (4 Mount Struts, No. 1, 2, 
15, and 16).
    C. Turbine Rear Frame Part Numbers 340-166-205-0, 340-166-206-0, 
340-166-207-0, 340-166-208-0, 340-166-209-0, 340-166-210-0, for all 
CFM56-7B SAC engine models (except -7B27A engine models). Refer to 
figure 805.

----------------------------------------------------------------------------------------------------------------
                                                 Inspection threshold  Inspection intervals       Inspection
     Figure index No.       Inspection location   (cycles since new)         (cycles)             reference
----------------------------------------------------------------------------------------------------------------
805......................  Strut/outer ring      25,000 * for -7B SAC  Refer to Figure 806   Refer to SB 72-
                            fillet radius on      (except business      * for -7B SAC         0579.*
                            trailing edge (A).    jet) engine models.   (except business
                                                                        jet) engine models.
                           Strut/hub fillet      19,000 * for -7B SAC  Refer to Figure 807
                            radius on leading     business jet engine   * for -7B SAC
                            edge (B).             models.               business jet engine
                                                                        models.
                           Strut/outer ring
                            fillet radius on
                            trailing edge (C1
                            below outer ring).
                           Strut/outer ring
                            fillet radius on
                            trailing edge (C2
                            above outer ring) .
----------------------------------------------------------------------------------------------------------------
Note: * Applicable to all inspection locations. If inspection is not performed, part must be removed.

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[GRAPHIC] [TIFF OMITTED] TR04FE08.002

    (g) After the effective date of this AD, we will not approve any 
alternative inspection intervals for these parts except as provided 
for in paragraph (j) of this AD.

TRFs With Unknown Cycles

    (h) If you cannot establish the number of cycles accumulated 
since new, remove or inspect the TRF within 300 cycles-in-service 
after the effective date of this AD. The CFM56-7B Engine Shop Manual 
(ESM) or air carrier's approved continuous airworthiness maintenance 
program (CAMP) contains information for inspecting the TRF.
    (i) You may install a TRF removed in paragraph (h) of this AD 
after the TRF passes an initial inspection for cracks. The CFM56-7B 
ESM or CAMP contains information on inspecting the TRF.

Alternative Methods of Compliance

    (j) The Manager, Engine Certification Office, has the authority 
to approve alternative methods of compliance for this AD if 
requested using the procedures found in 14 CFR 39.19.

Maintaining Records of the Mandatory Inspections

    (k) You have met the requirements of this AD by making the 
changes to the Engine Shop Manual as specified in paragraph (f) of 
this AD, and, for air carriers operating under part 121 of the 
Federal Aviation Regulations (14 CFR part 121), by modifying your 
continuous airworthiness maintenance plan to reflect those changes. 
You must maintain records of the mandatory inspections that result 
from those changes to the ALS according to the regulations governing 
your operation. You do not need to record each inspection as 
compliance to this AD. For air carriers operating under part 121, 
you may use the system established to comply with section 121.369.

Related Information

    (l) CFM International Service Bulletin CFM56-7B S/B 72-0579, 
Revision 1, dated October 27, 2006, contains information about Eddy 
Current inspection.
    (m) Contact Antonio Cancelliere, Aerospace Engineer, Engine 
Certification Office, FAA, Engine and Propeller Directorate, 12 New 
England Executive Park, Burlington, MA 01803; telephone (781) 238-
7751; fax (781) 238-7199, for more information about this AD.

    Issued in Burlington, Massachusetts, on January 23, 2008.
Peter A. White,
Assistant Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. E8-1830 Filed 2-1-08; 8:45 am]

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