AD 2001-04-06

[Federal Register Volume 66, Number 40 (Wednesday, February 28, 2001)]
[Rules and Regulations]
[Pages 12726-12729]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 01-4216]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-ANE-57-AD; Amendment 39-12124; AD 2001-04-06]
RIN 2120-AA64


Airworthiness Directives; CFM International, S.A. CFM56-3, -3B, 
and -3C Series Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
is applicable to CFM International, S.A. CFM56-3, -3B, and -3C series 
turbofan engines. This amendment requires that use of certain 
lubricants no longer on the manufacturer's approved list be 
discontinued. In addition, this amendment requires a one-time fan disk 
dovetail wear measurement, and if wear exceeds certain limits, requires 
an ultrasonic inspection for cracks in the fan disk, and, if necessary, 
removal from service of fan disks and replacement with serviceable 
parts. This amendment is prompted by reports of fan disk heavy wear and 
cracks. The actions specified by this amendment are intended to prevent 
fan disk failure, which could result in an uncontained engine failure 
and damage to the aircraft.

DATES: Effective date April 4, 2001. The incorporation by reference of 
certain publications listed in the regulations is approved by the 
Director of the Federal Register as of April 4, 2001.

ADDRESSES: The service information referenced in this AD may be 
obtained from CFM International, Technical Publications Department, 1 
Neumann Way, Cincinnati, OH 45215; telephone (513) 552-2800, fax (513) 
552-2816. This information may be examined at the FAA, New England 
Region, Office of the Regional Counsel, 12 New England Executive Park, 
Burlington, MA, or at the Office of the Federal Register, 800 North 
Capitol Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Glorianne Niebuhr, Aerospace Engineer, 
Engine Certification Office, FAA, Engine

[[Page 12727]]

and Propeller Directorate, 12 New England Executive Park, Burlington, 
MA 01803-5299; telephone (781) 238-7132, fax (781) 238-7199.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an airworthiness 
directive (AD) that is applicable to CFM International S.A. CFM56-3, -
3B, and -3C Series Turbofan Engines was published in the Federal 
Register on March 3, 2000 (65 FR 11505). That action proposed to 
require a one-time fan disk dovetail wear measurement, and if wear 
exceeds certain limits, require an ultrasonic inspection for cracks in 
the fan disk, and, if necessary, require removal from service of fan 
disks and replacement with serviceable parts. That action was prompted 
by reports of fan disk heavy wear and cracks. That condition, if not 
corrected, could result in an uncontained engine failure and damage to 
the aircraft.

Comments Received

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Compliance Intent

    One commenter suggests that the compliance intent of the AD would 
be met if an operator accomplished Boeing task card C72-31-02-2A-1 or -
2, and Boeing Aircraft Maintenance Manual (AMM) 72-31-02, tasks on page 
601. The FAA disagrees. The Boeing task card only describes the 
procedure for lubricating fan blade dovetails. In addition, the AMM 
does not lead the operator to perform ultrasonic inspection and does 
not explain how to gain serviceability.

When Inspection Is Not Required

    One commenter suggests that the information contained in paragraphs 
1.A. (1) and (2) of CFMI SB 72-854, Revision 2, should be added to the 
AD to clarify when the inspection is NOT required. The FAA partially 
agrees. The information is already included in the flowcharts in the 
referenced SB. However, to further clarify when an inspection is NOT 
required, information has been added to new paragraphs (h), (i) and (j) 
of this AD.

Requirements of Revision 1 and Revision 2

    One commenter is concerned that the requirements of CFMI CFM56-3 SB 
72-854 Revision 1 and CFMI CFM56-3 SB 72-854 Revision 2 are different 
and that the AD will result in another round of inspections after they 
have already been done according to Revision 1. Other commenters want 
to be sure that credit will be given for performing Revision 1 of the 
SB. The FAA partially agrees and clarification has been added to the AD 
to allow Revision 1 as a method of compliance. There is no technical 
difference between Revision 1 and 2. Revision 2 simply adds flowcharts 
for clarification.

Clarification of Wear Limits

    One commenter states that the wear limits in the SB are 
inconsistent with the wear limits in the AD (.004 inch vs. .005 inch). 
The FAA does not agree. There is no difference between the AD and the 
SB. The two measurements noted (.004 and .005) are applied in different 
contexts. The .004 inch limit in SB paragraph 1.A.(2) refers to the 
last inspection performed in accordance with the engine shop manual and 
is one of the conditions required to avoid the inspection per the AD. 
However, the .005 inch limit is a result of the on-wing inspection 
required by the AD to determine if the disk is serviceable or if 
further inspections are necessary.

Inspection Parameters

    One commenter asks that the second bullet in paragraph 1.A of the 
SB, which states that for ``fan disks relubricated with a currently 
recommended lubricant, inspection of these disks is due at 20,000 
cycles-since-new (CY)/35,000 hours-since-new (H) threshold-since-new or 
rebroached,'' be added to the compliance section of the AD to clarify 
when it is possible to wait until 20,000 cycles to perform the 
inspection. The FAA agrees with the intent of the second bullet in 
paragraph 1.A of the SB and clarification has been added to new 
paragraph (k) of the compliance section to further explain when it is 
possible to wait until 20,000 cycles to inspect.

Rebroached Fan Disks

    The manufacturer asks that a statement be added to the effectivity 
section of the AD that rebroached fan disks do not require an 
inspection per this AD. The FAA agrees and has added new paragraph (i) 
to the AD, stating that inspections will not be required for rebroached 
fan disks.

Where To Perform the Inspection

    One commenter requests that the fan disk inspections be performed 
at the shop visit level instead of on-wing. The commenter further 
states that there is a low failure rate and incidents that occurred 
resulted from the use of an uncommon lubricant. The FAA does not agree. 
The lubricant being discontinued was an approved lubricant. The 
lubricant has since been taken off of the approved lubricant list. But 
before that time, any and all operators had the possibility of being 
exposed. As stated in SB paragraph 1.A.(1), if the fan disk has used a 
currently approved lubricant and has the recommended configuration 
installed before 3,000 cycles/5250 hours, inspection is not required. 
Otherwise inspection per the AD is necessary to maintain a minimum 
acceptable level of safety. In addition, a cracked fan disk could lead 
to an uncontained failure. The risk analysis shows that the control 
program described in this AD meets the minimum level of safety.

Labor Requirement

    One commenter asks the FAA to add two hours for ultrasonic 
inspection to the labor requirement. The FAA does not agree. The two 
hours for ultrasonic inspection is already included in the estimated 
nine man-hours detailed in the AD. It is also spelled out in detail in 
paragraph 1.F.(4) of the SB.

Availability of Blade Replacements

    One commenter asks that the FAA revise the on-wing inspection 
requirement to a shop visit when it is necessary to install the 37 deg. 
fan blades. The commenter is concerned that blades are not always 
available and down time may result. The FAA does not agree. The 
manufacturer has informed the FAA that all parts should be readily 
available for purchase and installation. In addition, this method meets 
the minimum acceptable level of safety necessary for this program.

Wear Measurement Tool

    One commenter, who questions the accuracy and repeatability of the 
measuring tool with respect to the allowable max wear limit of .005 
inch, asks that the FAA consider eliminating the wear measurement tool 
in the inspection process. The FAA does not agree. The current wear 
measurement tool is acceptable for this inspection program. This issue 
was addressed in the beginning of the program. The .005 inch wear limit 
takes into consideration the accuracy and repeatability factor. In 
addition, new improvements have since been introduced to this tool and 
courses have been provided to explain how to use it properly. 
Repeatability and reproducibility tests were performed in overhaul 
shops in 1997. This is the current best practice that is compatible 
with existing maintenance constraints and practices.

[[Page 12728]]

Concurrence as Written

    One commenter concurs with the AD as written.
    After careful review of the available data, the FAA has determined 
that air safety and the public interest require the adoption of the 
rule with the changes described previously. The FAA has determined that 
these changes will neither increase the economic burden on any operator 
nor increase the scope of the AD.

Regulatory Impact

    This proposal does not have federalism implications, as defined in 
Executive Order 13132, because it would 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. Accordingly, 
the FAA has not consulted with state authorities prior to publication 
of this proposal.
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under the DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) if promulgated, 
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. A copy of the draft regulatory evaluation 
prepared for this action is contained in the Rules Docket. A copy of it 
may be obtained by contacting the Rules Docket at the location provided 
under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends part 39 of 
the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39--AIRWORTHINESS DIRECTIVES

    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]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

2001-04-06 CFM International: Amendment 39-12124. Docket 98-ANE-57-
AD.
    Applicability: CFM International, S.A (CFMI) CFM56-3, -3B, and -
3C series turbofan engines, installed on but not limited to Boeing 
737 series aircraft.

    Note 1: This airworthiness directive (AD) applies to each engine 
identified in the preceding applicability provision, regardless of 
whether it has been modified, altered, or repaired in the area 
subject to the requirements of this AD. For engines that have been 
modified, altered, or repaired so that the performance of the 
requirements of this AD is affected, the owner/operator must request 
approval for an alternative method of compliance in accordance with 
paragraph (l) of this AD. The request should include an assessment 
of the effect of the modification, alteration, or repair on the 
unsafe condition addressed by this AD; and, if the unsafe condition 
has not been eliminated, the request should include specific 
proposed actions to address it.

    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent fan disk failure, which could result in an 
uncontained engine failure and damage to the aircraft, accomplish 
the following:

Wear Measurement (Thrust Rating Category A Only)

    (a) For CFM56-3, -3B, and -3C series engines operating at the 
category A thrust rating on the effective date of this AD that have 
never previously operated at the category B or C thrust ratings, 
perform a one time fan disk dovetail wear measurement in accordance 
with section 2.B.(1) of Service Bulletin (SB) CFMI CFM56-3/-3B/-3C, 
No. 72-854, Revision 1, dated August 7, 1998, or section 2.B.(1) of 
SB CFMI CFM56-3/-3B/-3C, No. 72-854, Revision 2, dated November 29, 
1999, using the intervals defined in section 1.D.(1)(a)(1) and 
1.D.(1)(a)(2) of the SB's, and the current fan disk time and cycles 
on the effective date of the AD.

Inspection

    (1) Perform a local ultrasonic inspection for cracks in the fan 
disk in accordance with section 2.B.(2) of the SB, if required by 
the wear criteria described in section 1.D.(1)(b)1 of the SB.

Removal

    (i) Remove from service prior to further flight fan disks that 
do not meet the ultrasonic inspection criteria defined in paragraph 
2.B.(2)(d)8b of the SB, and replace with a serviceable part.
    (ii) Remove from service within 50 cycles-in-service (CIS), fan 
disks that meet the ultrasonic inspection criteria defined in 
paragraph 2.B.(2)(d)8b of the SB, if the wear measurement is greater 
than or equal to 9 mils.
    (2) Install dampers, as required, in accordance with the 
compliance times and criteria described in section 1.D.(1)(b)1 of 
the SB.

Wear Measurement (Thrust Rating Category A, if the Engine Was 
Previously Operated at Thrust Rating Categories B or C)

    (b) For CFM56-3, -3B, and -3C series engines operating at the 
category A thrust rating on the effective date of this AD that have 
previously operated at the category B or category C thrust ratings, 
perform a one-time fan disk dovetail wear measurement in accordance 
with section 2.B.(1) of SB CFMI CFM56-3/-3B/-3C, No. 72-854, 
Revision 1, dated August 7, 1998, or section 2.B.(1) of SB CFMI 
CFM56-3/-3B/-3C, No. 72-854, Revision 2, dated November 29, 1999, 
using the intervals defined in section 1.D.(1)(a)(1) and 
1.D.(1)(a)(2) of the SB's, and the current fan disk time and cycles 
on the effective date of the AD.

Inspection

    (1) Perform a local ultrasonic inspection for cracks in the fan 
disk in accordance with section 2.B.(2) of the SB, if required by 
the wear criteria described in section 1.D.(1)(b)2 of the SB.

Removal

    (i) Remove from service prior to further flight fan disks that 
do not meet the ultrasonic inspection criteria defined in paragraph 
2.B.(2)(d)8b of the SB, and replace with a serviceable part.
    (ii) Remove from service within 50 CIS, fan disks that meet the 
ultrasonic inspection criteria defined in paragraph 2.B.(2)(d)8b of 
the SB, if the wear measurement is greater than or equal to 9 mils.
    (2) Install dampers, as required, in accordance with the 
compliance times and criteria described in section 1.D.(1)(b)2 of 
the SB.

Wear Measurement (Thrust Rating Category B, Regardless of Whether the 
Engine Was Previously Operated at Thrust Rating Categories A or C)

    (c) For CFM56-3B and -3C series engines operating at the 
category B thrust rating on the effective date of this AD, 
regardless of whether the engine was previously operated at thrust 
rating categories A or C, perform a one-time fan disk dovetail wear 
measurement in accordance with section 2.B.(1) of CFMI CFM56-3/-3B/-
3C Service Bulletin (SB) No. 72-854, Revision 1, dated August 7, 
1998, or section 2.B.(1) of CFMI CFM56-3/-3B/-3C SB No. 72-854, 
Revision 2, dated November 29, 1999, using the intervals defined in 
section 1.D.(1)(a)(1) and 1.D.(1)(a)(2) of the SB's, and the current 
fan disk time and cycles on the effective date of the AD.

Inspection

    (1) Perform a local ultrasonic inspection for cracks in the fan 
disk in accordance with section 2.B.(2) of the SB, if required by 
the wear criteria described in section 1.D.(1)(c) of the SB.

Removal

    (i) Remove from service prior to further flight fan disks that 
do not meet the ultrasonic inspection criteria defined in paragraph 
2.B.(2)(d)8b of the SB, and replace with a serviceable part.
    (ii) Remove from service within 50 CIS, fan disks that meet the 
ultrasonic inspection

[[Page 12729]]

criteria defined in paragraph 2.B.(2)(d)8b of the SB, if the wear 
measurement is greater than or equal to 9 mils.
    (2) Remove and replace fan blades and install dampers, as 
required, in accordance with the compliance times and criteria 
described in section 1.D.(1)(c) of the SB.

Wear Measurement (Thrust Rating Category C, Regardless of Whether the 
Engine Was Previously Operated at Thrust Rating Categories A or B)

    (d) For CFM56-3C series engines operating at the category C 
thrust rating on the effective date of this AD, regardless of 
whether the engine was previously operated at category A or B thrust 
ratings, perform a one-time fan disk dovetail wear measurement in 
accordance with section 2.B.(1) of SB CFMI CFM56-3/-3B/-3C, No. 72-
854, Revision 1, dated August 7, 1998, or section 2.B.(1) of SB CFMI 
CFM56-3/-3B/-3C SB, No. 72-854, Revision 2, dated November 29, 1999, 
using the intervals defined in section 1.D.(1)(a)(1) and 
1.D.(1)(a)(2) of the SB's and the current fan disk time and cycles 
on the effective date of the AD.

Inspection

    (1) Perform a local ultrasonic inspection for cracks in the fan 
disk in accordance with section 2.B.(2) of the SB, if required by 
the wear criteria described in section 1.D.(1)(d) of the SB.

Removal

    (i) Remove from service prior to further flight fan disks that 
do not meet the ultrasonic inspection criteria defined in paragraph 
2.B.(2)(d)8b of the SB, and replace with a serviceable part.
    (ii) Remove from service within 50 CIS, fan disks that meet the 
ultrasonic inspection criteria defined in paragraph 2.B.(2)(d)8b of 
the SB, if the wear measurement is greater than or equal to 5 mils.
    (2) [Reserved]

Cleaning and Lubrication of Fan Disk/Blade

    (e) If the fan disk is determined to be serviceable, clean and 
lubricate the fan disk and fan blades using the instructions in 
paragraph 2.B.(2)(d)8d of the SB.

Definitions

    (f) The category A, B, and C thrust ratings listed in paragraphs 
(a) through (d) of this AD are defined in chapter 05 of the CFM56-3 
model series Engine Shop Manual, CFMI-TP.SM.5.

Lubricants

    (g) After the effective date of this AD, the following 
lubricants are no longer approved for use on the CFMI CFM56-3, -3B, 
and -3C series engines: Sandstrom 27A, ZIP D5460, Surf-kote A 1625, 
Tiolube 70 and Tiolube 75/75.

When Inspection Is Not Required

    (h) The actions required by paragraphs (a), (b), (c), and (d), 
(e) of this AD are not required if the fan disk has been equipped 
with configurations (1) or (2) below prior to reaching 3,000 cycles-
since-new, or 5,250 hours-since-new, whichever occurs first, and has 
never been relubricated using one of the lubricants identified in 
paragraph (g) of this AD:
    (1) For fan disks operating at a thrust rating of 20,000 pounds 
or less, the fan disk has either 25 deg. fan blades with dampers or 
37 deg. fan blades with or without dampers.
    (2) For fan disks operating at a thrust rating of more than 
20,000 pounds, the fan disk has 37 deg. fan blades with dampers.
    (i) Inspection is not required for fan disks that used 
lubricants identified in paragraph (g) but were then rebroached 
prior to exceeding the .004 inch wear limit, then were not 
lubricated with the lubricants identified in paragraph (g) AND were 
equipped with fan blade configurations specified either in sub-
paragraph (h)(1) or (h)(2) of this AD.
    (j) Inspection is also not required for fan disks that were 
inspected to and within Engine Shop Manual limits of .004 inch wear 
limit, then were not lubricated with the lubricants identified in 
paragraph (g) AND were equipped with fan blade configurations 
specified either in sub-paragraph (h)(1) or (h)(2) of this AD.

When Inspection Can Wait Until 20,000 Cycles-Since-New (CSN)/35,000 
Time-Since-New (TSN)

    (k) For disks that have never been relubricated since first 
manufacture using one of the lubricants identified in paragraph (g) 
of this AD, the inspections required by paragraphs (a), (b), (c), 
and (d) of this AD are required at 20,000 CSN or 35,000 hours TSN, 
whichever occurs first.

Alternative Methods of Compliance

    (l) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used if approved by the Manager, Engine Certification Office (ECO). 
Operators shall submit their request through an appropriate FAA 
Principal Maintenance Inspector, who may add comments and then send 
it to the Manager, ECO.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this airworthiness directive, 
if any, may be obtained from the ECO.

Ferry Flights

    (m) Special flight permits may be issued in accordance with 
Secs. 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 
21.197 and 21.199) to operate the aircraft to a location where the 
requirements of this AD can be accomplished.

Incorporation by Reference Material

    (n) The FAA has reviewed and approved the technical content of 
the listed CFMI SBs. The actions required by this AD shall be done 
in accordance with the following CFMI SBs:

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              Document No.                   Pages       Revision                       Date
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CFM56 -3/-3B/-3C, SB No. 72-854.........         1-39            1  August 7, 1998.
                                         -------------
      Total pages.......................           39
CFM56 -3/-3B/-3C, SB No. 72-854.........         1-40            2  November 29, 1999.
                                         -------------
      Total pages.......................           40
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    The incorporations by reference were approved by the Director of 
the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR 
part 51. Copies may be obtained from CFM International, Technical 
Publications Department, 1 Neumann Way, Cincinnati, OH 45215; 
telephone: (513) 552-2800, fax: (513) 552-2816. Copies may be 
inspected at the FAA, New England Region, Office of the Regional 
Counsel, 12 New England Executive Park, Burlington, MA 01803-5299; 
or at the Office of the Federal Register, 800 North Capitol Street, 
NW., suite 700, Washington, DC.

Effective Date

    (o) This amendment becomes effective on April 4, 2001.

    Issued in Burlington, Massachusetts, on February 12, 2001.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 01-4216 Filed 2-27-01; 8:45 am]
BILLING CODE 4910-13-P