AD 2012-14-09
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| engine | Pratt & Whitney Division | PW4050 | Airworthiness Directives; Pratt & Whitney (P&W) Division Turbofan Engines |
| engine | Pratt & Whitney Division | PW4052 | Airworthiness Directives; Pratt & Whitney (P&W) Division Turbofan Engines |
| engine | Pratt & Whitney Division | PW4056 | Airworthiness Directives; Pratt & Whitney (P&W) Division Turbofan Engines |
| engine | Pratt & Whitney Division | PW4060 | Airworthiness Directives; Pratt & Whitney (P&W) Division Turbofan Engines |
| engine | Pratt & Whitney Division | PW4060A | Airworthiness Directives; Pratt & Whitney (P&W) Division Turbofan Engines |
| engine | Pratt & Whitney Division | PW4060C | Airworthiness Directives; Pratt & Whitney (P&W) Division Turbofan Engines |
| engine | Pratt & Whitney Division | PW4062 | Airworthiness Directives; Pratt & Whitney (P&W) Division Turbofan Engines |
| engine | Pratt & Whitney Division | PW4062A | Airworthiness Directives; Pratt & Whitney (P&W) Division Turbofan Engines |
| engine | Pratt & Whitney Division | PW4152 | Airworthiness Directives; Pratt & Whitney (P&W) Division Turbofan Engines |
| engine | Pratt & Whitney Division | PW4156 | Airworthiness Directives; Pratt & Whitney (P&W) Division Turbofan Engines |
| engine | Pratt & Whitney Division | PW4156A | Airworthiness Directives; Pratt & Whitney (P&W) Division Turbofan Engines |
| engine | Pratt & Whitney Division | PW4158 | Airworthiness Directives; Pratt & Whitney (P&W) Division Turbofan Engines |
| engine | Pratt & Whitney Division | PW4160 | Airworthiness Directives; Pratt & Whitney (P&W) Division Turbofan Engines |
| engine | Pratt & Whitney Division | PW4164 | Airworthiness Directives; Pratt & Whitney (P&W) Division Turbofan Engines |
| engine | Pratt & Whitney Division | PW4164-1D | Airworthiness Directives; Pratt & Whitney (P&W) Division Turbofan Engines |
| engine | Pratt & Whitney Division | PW4164C | Airworthiness Directives; Pratt & Whitney (P&W) Division Turbofan Engines |
| engine | Pratt & Whitney Division | PW4164C-1D | Airworthiness Directives; Pratt & Whitney (P&W) Division Turbofan Engines |
| engine | Pratt & Whitney Division | PW4164C/B | Airworthiness Directives; Pratt & Whitney (P&W) Division Turbofan Engines |
| engine | Pratt & Whitney Division | PW4164C/B-1D | Airworthiness Directives; Pratt & Whitney (P&W) Division Turbofan Engines |
| engine | Pratt & Whitney Division | PW4168 | Airworthiness Directives; Pratt & Whitney (P&W) Division Turbofan Engines |
| engine | Pratt & Whitney Division | PW4168-1D | Airworthiness Directives; Pratt & Whitney (P&W) Division Turbofan Engines |
| engine | Pratt & Whitney Division | PW4168A | Airworthiness Directives; Pratt & Whitney (P&W) Division Turbofan Engines |
| engine | Pratt & Whitney Division | PW4168A-1D | Airworthiness Directives; Pratt & Whitney (P&W) Division Turbofan Engines |
| engine | Pratt & Whitney Division | PW4170 | Airworthiness Directives; Pratt & Whitney (P&W) Division Turbofan Engines |
| engine | Pratt & Whitney Division | PW4460 | Airworthiness Directives; Pratt & Whitney (P&W) Division Turbofan Engines |
| engine | Pratt & Whitney Division | PW4462 | Airworthiness Directives; Pratt & Whitney (P&W) Division Turbofan Engines |
| engine | Pratt & Whitney Division | PW4650 | Airworthiness Directives; Pratt & Whitney (P&W) Division Turbofan Engines |
Unsafe Condition
Reports of 3rd and 4th stage vane fractures in the low-pressure turbine (LPT) of certain PW4000-94'' and PW4000-100'' turbofan engines.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Dimensional inspections of LPT 3rd stage vanes and the rear turbine case. Inspection of LPT 4th stage vanes at the next LPT overhaul, with removal of vanes with non-conforming airfoil fillet radii and vanes with more than one strip and recoat repair. Disassembly and reassembly of the 2nd stage high-pressure turbine (HPT) rotor and 3rd stage LPT rotor at the next HPT and LPT overhauls.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within the specified compliance times for each action.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Pratt & Whitney PW4000-94'' and PW4000-100'' turbofan engines.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
We are adopting a new airworthiness directive (AD) for certain P&W PW4000 series turbofan engines. This AD was prompted by reports of 3rd and 4th stage vane fractures in the low-pressure turbine (LPT) of certain PW4000-94" and PW4000-100" turbofan engines. This AD requires dimensional inspections of LPT 3rd stage vanes and the rear turbine case, inspection of LPT 4th stage vanes at the next LPT overhaul and removal of vanes with non-conforming airfoil fillet radii and vanes with more than one strip and recoat repair. This AD also requires disassembly and reassembly of the 2nd stage high-pressure turbine (HPT) rotor and 3rd stage LPT rotor at the next HPT and LPT overhauls. We are issuing this AD to prevent 3rd and 4th stage vane fractures in the LPT, damage to the LPT rotor, uncontained engine failure, and damage to the airplane.
Applicability Source Text
Show captured applicability text from the source AD
(c) Applicability
This AD applies to the following Pratt & Whitney Division
turbofan engines:
(1) PW4000-94'' engine models PW4050, PW4052, PW4056, PW4152,
PW4156, PW4650, PW4060, PW4060A, PW4060C, PW4062, PW4062A, PW4156A,
PW4158, PW4160, PW4460, and PW4462 including models with any dash
number suffix.
(2) PW4000-100'' engine models PW4164, PW4164C, PW4164C/B,
PW4168, PW4168A, PW4164-1D, PW4164C-1D, PW4164C/B-1D, PW4168-1D,
PW4168A-1D, and PW4170.
Document Text
Show stored source text (verify against official source)
[Federal Register Volume 77, Number 192 (Wednesday, October 3, 2012)]
[Rules and Regulations]
[Pages 60288-60296]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2012-23791]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2012-0060; Directorate Identifier 2012-NE-02-AD;
Amendment 39-17123; AD 2012-14-09]
RIN 2120-AA64
Airworthiness Directives; Pratt & Whitney (P&W) Division Turbofan
Engines
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
-----------------------------------------------------------------------
SUMMARY: We are adopting a new airworthiness directive (AD) for certain
P&W PW4000 series turbofan engines. This AD was prompted by reports of
3rd and 4th stage vane fractures in the low-pressure turbine (LPT) of
certain PW4000-94'' and PW4000-100'' turbofan engines. This AD requires
dimensional inspections of LPT 3rd stage vanes and the rear turbine
case, inspection of LPT 4th stage vanes at the next LPT overhaul and
removal of vanes with non-conforming airfoil fillet radii and vanes
with more than one strip and recoat repair. This AD also requires
disassembly and reassembly of the 2nd stage high-pressure turbine (HPT)
rotor and 3rd stage LPT rotor at the next HPT and LPT overhauls. We are
issuing this AD to prevent 3rd and 4th stage vane fractures in the LPT,
damage to the LPT rotor, uncontained engine failure, and damage to the
airplane.
DATES: This AD is effective November 7, 2012.
ADDRESSES: For more information about this AD, contact James Gray,
Aerospace Engineer, Engine Certification Office, FAA, Engine &
Propeller Directorate, 12 New England Executive Park, Burlington, MA;
phone: 781-238-7742; fax: 781-238-7199; email: <a href="/cdn-cgi/l/email-protection#f298939f9781dc97dc9580938bb2949393dc959d84"><span class="__cf_email__" data-cfemail="d6bcb7bbb3a5f8b3f8b1a4b7af96b0b7b7f8b1b9a0">[email protected]</span></a>.
Examining the AD Docket
You may examine the AD docket on the Internet at <a href="http://www.regulations.gov">http://www.regulations.gov</a>; or in person at the Docket Management Facility
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 address for the
Docket Office (phone: 800-647-5527) is Document Management Facility,
U.S. Department of Transportation, Docket Operations, M-30, West
Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE.,
Washington, DC 20590.
[[Page 60289]]
FOR FURTHER INFORMATION CONTACT: James Gray, Aerospace Engineer, Engine
Certification Office, FAA, Engine & Propeller Directorate, 12 New
England Executive Park, Burlington, MA; phone: 781-238-7742; fax: 781-
238-7199; email: <a href="/cdn-cgi/l/email-protection#177d767a72643972397065766e5771767639707861"><span class="__cf_email__" data-cfemail="5d373c30382e7338733a2f3c241d3b3c3c733a322b">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION:
Discussion
We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR
part 39 to include an AD that would apply to the specified products.
That NPRM published in the Federal Register on March 2, 2012 (77 FR
12755). That NPRM proposed to require dimensional inspections of 3rd
stage vanes and the rear turbine case. That NPRM also proposed to
require inspection of 4th stage vanes at the next LPT overhaul and
removal of vanes with non-conforming airfoil fillet radii and vanes
with more than one strip and recoat repair. That NPRM also proposed to
require disassembly and reassembly of the 2nd stage HPT rotor and 3rd
stage LPT rotor at the next HPT and LPT overhauls.
Comments
We gave the public the opportunity to participate in developing
this AD. The following presents the comments received on the proposal
and the FAA's response to each comment.
Agreement With the Proposed AD
Two commenters, Boeing and FedEx, agreed with the intent of the
proposed AD.
Request To Change Compliance Time for the 4th Stage Vanes
One commenter, China Cargo Airlines, requested that we change the
inspection compliance time for the LPT 4th stage vanes from ``next LPT
overhaul'' to ``next engine overhaul.'' The commenter stated that LPT
overhauls are typically performed every other shop visit, which could
be in six-to-eight years. The commenter thought that the risk of having
a 4th stage vane failure during that time was too high.
We do not agree. We determined that performing the inspections at
the next LPT overhaul after the effective date of the AD provides an
acceptable level of safety, and that we do not need to reduce the
interval. We did not change the AD.
Request for Credit for Prior Compliance
FedEx requested that a statement be included authorizing credit for
prior compliance as they have already been performing the requirements
of the proposed AD.
We do not agree. Paragraph (e) of the proposed AD already allows
credit for prior compliance. That paragraph states to comply with the
AD within the compliance times specified, unless already done. We did
not change the AD.
Request To Reference Pratt & Whitney Special Instruction No. 17F-09
One commenter, Martinair Holland, requested that we add a reference
to Pratt & Whitney Special Instruction No. 17F-09 as an alternate
method of compliance (AMOC) for paragraph (e)(1)(iii). The commenter
stated that they have been checking the 3rd stage vanes for adequate
engagement using that Special Instruction.
We do not agree. The AD requires dimensional inspections that are
not included in Special Instruction No. 17F-09. Also, we do not include
AMOCs in the requirements of an AD. You may, however, seek an AMOC
using the procedures specified in the AD. We did not add that Special
Instruction reference to the AD.
Request To Add Service Bulletins as Alternate Methods of Compliance
Martinair Holland, United Airlines, and Onur Air, requested that we
add references to Pratt & Whitney Service Bulletins (SBs) PW4ENG 72-
798, PW4ENG 72-804, and PW4G-100-72-221, as alternate methods of
compliance to paragraph (e)(1)(v). The commenters stated that they have
been inspecting the LPT 4th stage vanes using these SBs.
We do not agree. Paragraph (e) of the proposed AD states to comply
with the AD within the compliance times specified, unless already done.
If you have already done the proposed actions, then no further action
is required to comply with paragraph (e)(1)(v). Also, as noted above,
we do not include AMOCs in the requirements of an AD. We did not change
the AD.
Request To Include the Part Numbers (P/Ns) of the LPT 4th Stage Vanes
Pratt & Whitney requested that we include the P/Ns of the LPT 4th
stage vanes that are subject to the one-time strip and recoat
requirement. The commenter stated that it is possible that future
designs of LPT 4th stage vanes would not be restricted to a single
strip and recoat requirement.
We agree. We listed the P/Ns of the affected LPT 4th stage vanes in
the AD.
Request To Define the Word ``Guidance''
United Airlines requested that we define the word ``guidance''
which we used in paragraph (g) of the proposed AD, or, that we revise
the wording to specifically detail the inspection/build procedure to be
used. The commenter states that using the term ``guidance'' does not
denote a specific requirement and only suggests a general direction to
be followed.
We agree. Use of the word ``guidance'' in this AD may have caused
confusion. We deleted the ``guidance'' paragraphs listed under Related
Information from the AD.
Request To Update Guidance Service Information
Pratt & Whitney and United Parcel Service Co. (UPS) requested that
we add the words ``or later'' after the service information date
references in paragraph (g) of the proposed AD. They also requested
that we clarify that the referenced service information could be
updated, and compliance to that updated service information would be
acceptable. One of the commenters was concerned that service
information listed as guidance would be controlled in the same way as
service information that is incorporated by reference in the AD.
We do not agree. We do not know how documents will be revised in
the future. This AD, however, was revised to remove references to
related service information, and therefore the comment no longer
applies. We did not change the AD.
Request To Remove the Term ``Overhaul''
United Airlines and UPS requested that we remove the term
``overhaul,'' such as ``LPT overhaul'' and ``HPT overhaul'' from the
proposed AD compliance, as the term ``overhaul'' is not industry
standard and therefore subjective. The commenters suggested a few
alternatives to use instead of the term ``overhaul.''
We partially agree. We do not agree that the term ``overhaul''
should be removed, but we do agree that it should be defined. We added
a definition paragraph which states that, for the purpose of this AD,
an overhaul is when all disks in the rotor are removed from the engine
and the blades are removed.
Request To Clarify Approved Methods of Compliance
UPS requested that we clarify that the service information listed
under Related Information are approved methods of compliance to the
proposed AD. They further stated that, as-written, it is not clear that
they are approved methods of compliance.
We agree that the AD should be clarified. We revised the AD by
[[Page 60290]]
removing references to related service information.
Request To Duplicate the Strip and Recoat Requirements
United Airlines requested that we duplicate the strip and recoat
requirements and make them part of Inspection/Check-01 or Inspection/
Check-03 of the PW4000 Engine Cleaning Inspection and Repair (CIR)
Manual. The commenter stated that the strip and recoat limits are
currently located in repair-14 of the PW4000 CIR Manual, but repair-14
is not always required to return a vane cluster to service. The
commenter stated that the strip and recoat requirements need to be part
of the normal inspection process.
We do not agree. The AD mandates that the inspection be performed
once, at the next LPT overhaul. That inspection will purge the fleet of
LPT 4th stage vanes that have had more than one strip and recoat
repair. After that inspection, LPT 4th stage vanes are not allowed to
have more than one strip and recoat repair, as specified in the
installation prohibition paragraph (f). Revising the engine manuals to
relocate the inspection requirements is unnecessary. We did not change
the AD.
Request To Remove Reference to 4th Stage Vanes With an Unknown Number
of Strip and Recoat Repairs
United Airlines stated that there is no way to identify vanes with
an unknown number of strip and recoat repairs. The commenter stated
that if there were no markings on the vane, it would indicate that no
strip and recoat repairs were performed. This could lead to scrapping
vanes that could otherwise be repaired and returned to service.
We agree. We changed the AD to eliminate the reference to LPT 4th
stage vanes with an unknown number of strip and recoat repairs.
Request To Make the CIR Inspections More Specific
United Airlines requested that in proposed AD paragraph (e)(1)(iv)
we make the CIR inspections more specific for the LPT case dimensions.
The commenter stated that there are different ways to perform the
measurements and it is not clear whether the dimension to measure is
based on an average or an individual diametric dimension.
We do not agree. A specific measurement technique is not defined
because multiple measurement techniques exist that are acceptable. The
only diametric dimensional inspection required by the AD is index 24,
which would be acceptable to measure based on an average dimension. We
did not change the AD.
Request To Change ``Ensure Adequate Engagement''
United Airlines requested that in proposed AD paragraphs
(e)(1)(iii) and (e)(1)(iv), we change ``ensure adequate engagement'' to
``dimensionally inspect the applicable LPT case slot serviceable
dimensions and 3rd stage vane serviceable dimensions per the
appropriate CIR.'' The commenter also requested that we list the
specific dimensions to inspect by index number. The commenter stated
that no mechanic can deduce what an adequate engagement is because it
is not specific enough.
We agree. We changed paragraph (e)(1)(iii) to ``dimensionally
examine index 13 through index 34 of the LPT 3rd stage vane cluster
assembly.'' We also changed paragraph (e)(1)(iv) to ``dimensionally
examine index 23 and index 24 of the vane engagement slots on the rear
turbine case, where the 3rd stage vane is installed.'' We also listed
the specific dimensions to inspect by index number, and included the
supporting figures in this AD.
Request To Eliminate Paragraphs
United Airlines requested that we eliminate paragraphs (e)(1)(ii)
through (e)(1)(iv) and (e)(2). The commenter stated that these
paragraphs are related to procedures that are in the engine manual that
operators are already performing. If they are left in the AD, they will
add a significant burden in the amount of time and paperwork required
to manage and verify compliance to the AD.
We do not agree. The actions in the paragraphs the commenter wants
eliminated from the AD represent changes to the manuals that were
specifically incorporated to address 3rd and 4th stage vane failures.
Although air carriers operating under 14 Code of Federal Regulations
(CFR) Part 121 are likely using the most current versions of the engine
manuals, not all operators, for example, part 91 operators, may be
required to incorporate the latest versions of the engine manuals.
Therefore, we must maintain these requirements in the AD to ensure that
all operators comply to resolve the unsafe condition. We did not change
the AD.
Revision to Cost of Compliance
In reviewing the cost of compliance estimate made in the NPRM (77
FR 12755, March 2, 2012), we determined that we were unable to
substantiate our prorated cost estimate for limiting the number of
strip and recoat repairs since we do not know how many vanes are
operating with more than one strip and recoat repair. We, therefore,
removed the estimate of the useful part life expectancy and only
included the replacement parts cost. The total cost estimate changed
from $32,147,170 to $9,214,170.
Conclusion
We reviewed the relevant data, considered 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:
<bullet> Are consistent with the intent that was proposed in the
NPRM (77 FR 12755, March 2, 2012) for correcting the unsafe condition;
and
<bullet> Do not add any additional burden upon the public than was
already proposed in the NPRM (77 FR 12755, March 2, 2012).
We also determined that these changes will not increase the
economic burden on any operator or increase the scope of the AD.
Costs of Compliance
We estimate that this AD affects 807 engines installed on airplanes
of U.S. registry. We estimate that it will take 2 work-hours per engine
to perform the LPT 3rd stage vane cluster assembly and rear turbine
case inspections. The average labor rate is $85 per work-hour. We
expect that about 1,870 LPT 4th stage vane cluster assemblies will be
found with the non-conforming casting identification. Replacement parts
cost about $4,854. Based on these figures, we estimate the cost of the
AD on U.S. operators to be $9,214,170.
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
[[Page 60291]]
products identified in this rulemaking action.
Regulatory Findings
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),
(3) Will not affect intrastate aviation in Alaska, and
(4) 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.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
Adoption of the Amendment
Accordingly, under the authority delegated to me by the
Administrator, the FAA 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 (AD):
2012-14-09 Pratt & Whitney Division: Amendment 39-17123; Docket No.
FAA-2012-0060; Directorate Identifier 2012-NE-02-AD.
(a) Effective Date
This AD is effective November 7, 2012.
(b) Affected ADs
None.
(c) Applicability
This AD applies to the following Pratt & Whitney Division
turbofan engines:
(1) PW4000-94'' engine models PW4050, PW4052, PW4056, PW4152,
PW4156, PW4650, PW4060, PW4060A, PW4060C, PW4062, PW4062A, PW4156A,
PW4158, PW4160, PW4460, and PW4462 including models with any dash
number suffix.
(2) PW4000-100'' engine models PW4164, PW4164C, PW4164C/B,
PW4168, PW4168A, PW4164-1D, PW4164C-1D, PW4164C/B-1D, PW4168-1D,
PW4168A-1D, and PW4170.
(d) Unsafe Condition
This AD was prompted by reports of 3rd and 4th stage vane
fractures in the low-pressure turbine (LPT) of certain PW4000-94''
and PW4000-100'' turbofan engines. These fractures caused an
uncontained engine failure and an LPT case puncture, and resulted in
multiple in flight shutdowns. We are issuing this AD to prevent 3rd
and 4th stage vane fractures in the LPT, damage to the LPT rotor,
uncontained engine failure, and damage to the airplane.
(e) Compliance
Comply with this AD within the compliance times specified,
unless already done.
(1) At the next LPT overhaul, do the following:
(i) Remove LPT 4th stage vanes that have a P/N listed in Table 1
to paragraph (e) of this AD from service if more than one strip and
recoat repair has been performed.
Table 1 to Paragraph (e)--Affected LPT 4th Stage Vane P/Ns
------------------------------------------------------------------------
------------------------------------------------------------------------
50N174 50N674-01 51N174-001 51N374-001 52N574-01
50N474-01 50N774-01 51N174-002 51N674-01 52N674-01
50N474-001 50N774-001 51N174-003 52N274-01 51N774-01
50N574-01 51N174-01 51N374-01 52N474-01 52N774-01
------------------------------------------------------------------------
(ii) Re-assemble the 3rd stage LPT rotor blades by alternating
heavy blades next to light blades and balancing blades of similar
weights 180 degrees across the rotor.
(iii) Dimensionally examine index 13 through index 34 of the LPT
3rd stage vane cluster assembly. Use Table 2 to paragraph (e) of
this AD and Figure 1, Figure 2, and Figure 3 to paragraph (e) of
this AD to determine whether the vane is eligible for installation.
Table 2 to Paragraph (e)--Determination of Vane Eligibility
----------------------------------------------------------------------------------------------------------------
Inspect: Eligible for installation limits:
----------------------------------------------------------------------------------------------------------------
13.......................................... 1.820-1.830 inches (46.23-46.48 mm).
14.......................................... 1.920-1.930 inches (48.77-49.02 mm).
15.......................................... 3.200 inches (81.280 mm) Basic.
16.......................................... 0.900 inch (22.860 mm) Basic.
17.......................................... 0.365 inch (9.271 mm) Basic.
18.......................................... 0.350 inch (8.890 mm) Basic.
19.......................................... 0.160 inch (4.064 mm) Basic.
20.......................................... 0.772 inch (19.609 mm) Basic.
21.......................................... 72[deg] Basic.
22.......................................... 22.382 inch (568.503 mm) Radius--Origin on Plane S Basic.
23.......................................... 21.052 inch (534.721 mm) Radius--Origin on Plane S, concentric
with Index 8 Basic.
24.......................................... Angle from Plane S to Plane SL 3[deg]4'37'' Basic.
25.......................................... Angle from Plane S to Plane SM 6[deg]9'14'' Basic.
26.......................................... 90[deg] Basic for typical airfoil section.
27:
Distance from rear foot outer diameter
surface to airfoil section along Planes
S, SL, and SM.
For Section B-B:.................... 5.241 inches (133.121 mm).
[[Page 60292]]
For Section E-E:.................... 3.181 inches (80.797 mm).
For Section J-J:.................... 1.935 inches (49.149 mm).
28:
Airfoil chord at Section J-J (1.935 1.346 inches (34.188 mm) minimum.
inches (49.149 mm) from rear foot outer
diameter surface at Planes S, SL, and
SM).
At Section E-E (3.181 inches (80.797 mm) 1.314 inches (33.376 mm) minimum.
from rear foot outer diameter surface
at Planes S, SL, and SM).
At Section B-B (5.241 inches (133.121 1.188 inches (30.175 mm) minimum.
mm) from rear foot outer diameter
surface at Planes S, SL, and SM).
29:
Airfoil thickness at Section J-J (1.935 0.239 inch (6.071 mm) minimum.
inches (49.149 mm) from rear foot outer
diameter surface at Planes S, SL, and
SM).
At Section E-E (3.181 inches (80.797 mm) 0.183 inch (4.648 mm) minimum.
from rear foot outer diameter surface
at Planes S, SL, and SM).
At Section B-B (5.241 inches (133.121 0.139 inch (3.531 mm) minimum.
mm) from rear foot outer diameter
surface at Planes S, SL, and SM).
30:
Distance to trailing edge measurement... 0.062 inch (1.575 mm).
31:
Airfoil trailing edge thickness......... 0.030 inch (0.762 mm) minimum.
32:
Dimension............................... 0.315-0.324 inch (8.001-8.230 mm) diameter.
33:
Dimension............................... 6.785-6.795 inches (172.34-172.59 mm).
34:
Dimension............................... 0.692-0.714 inch (17.58-18.14 mm).
----------------------------------------------------------------------------------------------------------------
BILLING CODE 4910-13-P
[[Page 60293]]
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BILLING CODE 4910-13-C
(iv) Dimensionally examine index 23 and index 24 of the vane
engagement slots on the rear turbine case, where the 3rd stage vane
is installed. Use Table 3 to paragraph (e) of this AD and Figure 4
to paragraph (e) of this AD to determine whether the case is
eligible for installation.
Table 3 to Paragraph (e)--Determination of Case Eligibility
------------------------------------------------------------------------
Inspect: Eligible for installation limits:
------------------------------------------------------------------------
23............................... 1.875 inch (47.625 mm) minimum.
24............................... 0.097 inch (2.464 mm) minimum.
------------------------------------------------------------------------
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(v) Inspect the 44 LPT 4th stage vane cluster assemblies P/N
52N774-01 for casting identification ``51N554AT 1447 2S1C1'' and P/N
52N674-01 for casting identification ``51N454AT 655 2S1C1.'' Remove
the vane cluster assembly from service if either of these casting
identifications is found.
(2) At the next high-pressure turbine (HPT) overhaul, re-
assemble the 2nd stage HPT rotor blades by alternating heavy blades
next to light blades and balancing blades of similar weights 180
degrees across the rotor.
(f) Installation Prohibition
After the effective date of this AD, do not install or reinstall
into any engine any LPT 4th stage vanes with a P/N listed in Table 1
to paragraph (e) of this AD that are at piece-part exposure and have
had more than one strip and recoat repair.
(g) Definitions
(1) For the purpose of this AD, an HPT or LPT overhaul occurs
when all disks in the rotor are removed from the engine and the
blades are removed.
(2) For the purpose of this AD, piece-part exposure means that
the part is removed from the engine and completely disassembled.
(h) Alternative Methods of Compliance (AMOCs)
The Manager, Engine Certification Office, FAA, may approve AMOCs
for this AD. Use the procedures found in 14 CFR 39.19 to make your
request.
(i) Related Information
For more information about this AD, contact James Gray,
Aerospace Engineer, Engine Certification Office, FAA, Engine &
Propeller Directorate, 12 New England Executive Park, Burlington,
MA; phone: 781-238-7742; fax: 781-238-7199; email:
<a href="/cdn-cgi/l/email-protection#284249454d5b064d064f5a4951684e4949064f475e"><span class="__cf_email__" data-cfemail="6b010a060e18450e450c190a122b0d0a0a450c041d">[email protected]</span></a>.
(j) Material Incorporated by Reference
None.
Issued in Burlington, Massachusetts, on September 20, 2012.
Diane M. Cook,
Acting Manager, Engine & Propeller Directorate, Aircraft Certification
Service.
[FR Doc. 2012-23791 Filed 10-2-12; 8:45 am]
BILLING CODE 4910-13-P
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Retrieved: Apr 4, 2026
Rights: U.S. Government Public Domain
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