60288 Federal Register / Vol. 77, No. 192 / Wednesday, October 3, 2012 / Rules and Regulations 

Alert Service Bulletin 777–32A0082, dated 

December 9, 2010. Do all applicable related 

investigative and corrective actions before 

further flight. 

(h) Definition 

For the purposes of this AD, chicken-wire 

cracks are defined as cracks that occur when 

stress created in the chrome deposit during 

plating are relieved. The cracks are evident 

in the deposited chrome when viewed from 

a perpendicular plane as a pattern similar to 

chicken wire. Crack size can vary with 

plating conditions. 

(i) Exceptions to Service Information 

(1) Where Boeing Alert Service Bulletin 

777–32A0082, dated December 9, 2010, 

specifies a compliance time after the original 

issue date of that service bulletin, this AD 

requires compliance within the specified 

compliance time after the effective date of 

this AD. 

(2) Where Boeing Alert Service Bulletin 

777–32A0082, dated December 9, 2010, 

specifies use of Royco 11MS grease for the 

lubrication required by paragraph (g) of this 

AD, this AD also allows use of MIL–PRF– 

32014 grease. 

(j) Optional Actions for Compliance With 

Paragraph (g) of This AD 

(1) Doing the detailed and magnetic 

particle inspections in accordance with Part 

2 of the Accomplishment Instructions of 

Boeing Special Attention Service Bulletin 

777–32–0080, dated July 10, 2008; or Boeing 

Special Attention Service Bulletin 777–32– 

0080, Revision 1, dated April 16, 2009; is 

considered acceptable for compliance with 

the inspections of the center axle of the MLG 

required by paragraph (g) of this AD. 

(2) Accomplishment of all applicable 

actions specified in and in accordance with 

the Accomplishment Instructions of Boeing 

Service Bulletin 777–32–0085, dated April 

14, 2011, is considered acceptable for 

compliance with the requirements of 

paragraph (g) of this AD. 

(k) Special Flight Permit 

Special flight permits may be issued in 

accordance with sections 21.197 and 21.199 

of the Federal Aviation Regulations (14 CFR 

21.197 and 21.199) to operate the airplane to 

a location where the airplane can be 

modified (if the operator elects to do so), if 

the flight is operated as a non-revenue flight. 

(l) Alternative Methods of Compliance 

(AMOCs) 

(1) The Manager, Seattle Aircraft 

Certification Office (ACO), FAA, has the 

authority to approve AMOCs for this AD, if 

requested using the procedures found in 14 

CFR 39.19. In accordance with 14 CFR 39.19, 

send your request to your principal inspector 

or local Flight Standards District Office, as 

appropriate. If sending information directly 

to the manager of the ACO, send it to the 

attention of the person identified in the 

Related Information section of this AD. 

Information may be emailed to: 9-ANMSeattle-ACO-AMOC-Requests@faa.gov. 

(2) Before using any approved AMOC, 

notify your appropriate principal inspector, 

or lacking a principal inspector, the manager 

of the local flight standards district office/ 

certificate holding district office. 

(3) An AMOC that provides an acceptable 

level of safety may be used for any repair 

required by this AD if it is approved by the 

Boeing Commercial Airplanes Organization 

Designation Authorization (ODA) that has 

been authorized by the Manager, Seattle 

ACO, to make those findings. For a repair 

method to be approved, the repair must meet 

the certification basis of the airplane and the 

approval must specifically refer to this AD. 

(m) Related Information 

For more information about this AD, 

contact Melanie Violette, Aerospace 

Engineer, Airframe Branch, ANM–120S, 

FAA, Seattle Aircraft Certification Office 

(ACO), 1601 Lind Avenue SW., Renton, WA 

98057–3356; phone: 425–917–6422; fax: 425– 

917–6590; email: Melanie.violette@faa.gov. 

(n) Material Incorporated by Reference 

(1) The Director of the Federal Register 

approved the incorporation by reference 

(IBR) of the service information listed in this 

paragraph under 5 U.S.C. 552(a) and 1 CFR 

part 51. 

(2) You must use the following service 

information to do the actions required by this 

AD, unless the AD specifies otherwise. 

(i) Boeing Alert Service Bulletin 777– 

32A0082, dated December 9, 2010. 

(ii) Boeing Service Bulletin 777–32–0085, 

dated April 14, 2011. 

(iii) Boeing Special Attention Service 

Bulletin 777–32–0080, dated July 10, 2008. 

(iv) Boeing Special Attention Service 

Bulletin 777–32–0080, Revision 1, dated 

April 16, 2009. 

(3) For service information identified in 

this AD, contact Boeing Commercial 

Airplanes, Attention: Data & Services 

Management, P. O. Box 3707, MC 2H–65, 

Seattle, WA 98124–2207; phone: 206–544– 

5000, extension 1; fax: 206–766–5680; 

Internet https://www.myboeingfleet.com. 

(4) You may review copies of the 

referenced service information at the FAA, 

Transport Airplane Directorate, 1601 Lind 

Avenue SW., Renton, WA. For information 

on the availability of this material at the 

FAA, call 425–227–1221. 

(5) You may also review copies of the 

service information that is incorporated by 

reference at the National Archives and 

Records Administration (NARA). For 

information on the availability of this 

material at NARA, call 202–741–6030, or go 

to http://www.archives.gov/federal-register/

cfr/ibr-locations.html. 

Issued in Renton, Washington, on 

September 19, 2012. 

Ali Bahrami, 

Manager, Transport Airplane Directorate, 

Aircraft Certification Service. 

[FR Doc. 2012–23790 Filed 10–2–12; 8:45 am] 

BILLING CODE 4910–13–P 

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 lowpressure 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: 

james.e.gray@faa.gov. 

Examining the AD Docket 

You may examine the AD docket on 

the Internet at http:// 

www.regulations.gov; 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. 


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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: james.e.gray@faa.gov. 

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 sixto-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 


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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: 

• Are consistent with the intent that 

was proposed in the NPRM (77 FR 

12755, March 2, 2012) for correcting the 

unsafe condition; and 

• 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 


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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 

■ 1. The authority citation for part 39 

continues to read as follows: 

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

§ 39.13 [Amended] 

■ 2. The FAA amends § 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 lowpressure 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° 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°4′37′′ 

Basic. 

25 ............................................................................................................................................................. Angle from Plane S to Plane SM 6°9′14′′ 

Basic. 

26 ............................................................................................................................................................. 90° 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). 


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TABLE 2 TO PARAGRAPH (E)—DETERMINATION OF VANE ELIGIBILITY—Continued 

Inspect: Eligible for installation limits: 

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 inches (49.149 mm) from rear foot outer diameter surface at 

Planes S, SL, and SM).

1.346 inches (34.188 mm) minimum. 

At Section E–E (3.181 inches (80.797 mm) from rear foot outer diameter surface at Planes S, 

SL, and SM).

1.314 inches (33.376 mm) minimum. 

At Section B–B (5.241 inches (133.121 mm) from rear foot outer diameter surface at Planes S, 

SL, and SM).

1.188 inches (30.175 mm) minimum. 

29: 

Airfoil thickness at Section J–J (1.935 inches (49.149 mm) from rear foot outer diameter surface 

at Planes S, SL, and SM).

0.239 inch (6.071 mm) minimum. 

At Section E–E (3.181 inches (80.797 mm) from rear foot outer diameter surface at Planes S, 

SL, and SM).

0.183 inch (4.648 mm) minimum. 

At Section B–B (5.241 inches (133.121 mm) from rear foot outer diameter surface at Planes S, 

SL, and SM).

0.139 inch (3.531 mm) minimum. 

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 


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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. 

TABLE 3 TO PARAGRAPH (e)—DETERMINATION OF CASE ELIGIBILITY— 

Continued 

Inspect: Eligible for installation limits: 

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 piecepart 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: 

james.e.gray@faa.gov. 

(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 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2011–1411; Directorate 

Identifier 2011–NM–074–AD; Amendment 

39–17206; AD 2012–19–11] 

RIN 2120–AA64 

Airworthiness Directives; The Boeing 

Company Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Final rule. 

SUMMARY: We are adopting a new 

airworthiness directive (AD) for certain 

The Boeing Company Model 737 

airplanes. This AD was prompted by a 

report of a flightcrew not receiving an 

aural warning during a lack of cabin 

pressurization event. This AD requires 

incorporating design changes to 

improve the reliability of the cabin 

altitude warning system by installing a 

redundant cabin altitude pressure 

switch, replacing the aural warning 

module (AWM) with a new or reworked 

AWM, and changing certain wire 

bundles or connecting certain 

previously capped and stowed wires as 


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