Federal Register / Vol. 71, No. 188 / Thursday, September 28, 2006 / Rules and Regulations 56861 

TABLE 1.—CREDIT SERVICE BULLETINS

BAE Systems (Operations) Limited Inspection 

Service Bulletin Revision level Date 

ISB.53–005 ........................................................................... Revision 1 ............................................................................ April 19, 1985. 

ISB.53–067 ........................................................................... Revision 1 ............................................................................ February 16, 1990. 

Revision 2 ............................................................................ February 16, 2004. 

Alternative Methods of Compliance 

(AMOCs) 

(k)(1) The Manager, International Branch, 

ANM–116, Transport Airplane Directorate, 

FAA, has the authority to approve AMOCs 

for this AD, if requested in accordance with 

the procedures found in 14 CFR 39.19. 

(2) Before using any AMOC approved in 

accordance with § 39.19 on any airplane to 

which the AMOC applies, notify the 

appropriate principal inspector in the FAA 

Flight Standards Certificate Holding District 

Office. 

Related Information 

(l) British airworthiness directive G–2005–

0020, dated July 6, 2005, also addresses the 

subject of this AD. 

Material Incorporated by Reference 

(m) You must use BAE Systems 

(Operations) Limited Inspection Service 

Bulletin ISB.53–005, Revision 2, dated 

February 16, 2004; and BAE Systems 

(Operations) Limited Inspection Service 

Bulletin ISB.53–067, Revision 3, dated June 

27, 2005; to perform the actions that are 

required by this AD, unless the AD specifies 

otherwise. The Director of the Federal 

Register approved the incorporation by 

reference of these documents in accordance 

with 5 U.S.C. 552(a) and 1 CFR part 51. 

Contact British Aerospace Regional Aircraft 

American Support, 13850 Mclearen Road, 

Herndon, Virginia 20171, for a copy of this 

service information. You may review copies 

at the Docket Management Facility, U.S. 

Department of Transportation, 400 Seventh 

Street, SW., Room PL–401, Nassif Building, 

Washington, DC; on the Internet at http:// 

dms.dot.gov; or at the National Archives and 

Records Administration (NARA). For 

information on the availability of this 

material at the NARA, call (202) 741–6030, 

or go to http://www.archives.gov/ 

federal_register/code_of_federal_regulations/ 

ibr_locations.html. 

Issued in Renton, Washington, on 

September 15, 2006. 

Kalene C. Yanamura, 

Acting Manager, Transport Airplane 

Directorate, Aircraft Certification Service. 

[FR Doc. 06–8231 Filed 9–27–06; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2006–24865; Directorate 

Identifier 2005–NM–194–AD; Amendment 

39–14771; AD 2006–20–02] 

RIN 2120–AA64 

Airworthiness Directives; Boeing 

Model 747 Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), Department of 

Transportation (DOT). 

ACTION: Final rule. 

SUMMARY: The FAA is superseding an 

existing airworthiness directive (AD), 

which applies to certain Boeing Model 

747 airplanes. That AD currently 

requires inspections to detect 

disbonding, corrosion, and cracking at 

the longitudinal rows of fasteners in the 

bonded skin panels in section 41 of the 

fuselage, and repair, if necessary. This 

new AD adds airplanes to the 

applicability, and requires new 

inspections of airplanes that may have 

Alodine-coated rivets installed. This AD 

results from a report of cracking 

discovered in a skin lap joint that was 

previously inspected using the eddy 

current method. We are issuing this AD 

to prevent rapid decompression of the 

airplane due to disbonding and 

subsequent cracking of the skin panels. 

DATES: This AD becomes effective 

November 2, 2006. 

The Director of the Federal Register 

approved the incorporation by reference 

of a certain publication listed in the AD 

as of November 2, 2006. 

On November 27, 1996 (61 FR 57994, 

November 12, 1996), the Director of the 

Federal Register approved the 

incorporation by reference of Boeing 

Alert Service Bulletin 747–53A2409, 

dated September 26, 1996. 

ADDRESSES: You may examine the AD 

docket on the Internet at http:// 

dms.dot.gov or in person at the Docket 

Management Facility, U.S. Department 

of Transportation, 400 Seventh Street, 

SW., Nassif Building, Room PL–401, 

Washington, DC. 

Contact Boeing Commercial 

Airplanes, P.O. Box 3707, Seattle, 

Washington 98124–2207, for service 

information identified in this AD. 

FOR FURTHER INFORMATION CONTACT: Ivan 

Li, Aerospace Engineer, Airframe 

Branch, ANM–120S, FAA, Seattle 

Aircraft Certification Office, 1601 Lind 

Avenue, SW., Renton, Washington 

98057–3356; telephone (425) 917–6437; 

fax (425) 917–6590. 

SUPPLEMENTARY INFORMATION: 

Examining the Docket 

You may examine the airworthiness 

directive (AD) docket on the Internet at 

http://dms.dot.gov or in person at the 

Docket Management Facility office 

between 9 a.m. and 5 p.m., Monday 

through Friday, except Federal holidays. 

The Docket Management Facility office 

(telephone (800) 647–5227) is located on 

the plaza level of the Nassif Building at 

the street address stated in the 

ADDRESSES section. 

Discussion 

The FAA issued a notice of proposed 

rulemaking (NPRM) to amend 14 CFR 

part 39 to include an AD that 

supersedes AD 96–23–02, amendment 

39–9807 (61 FR 57994, November 12, 

1996). The existing AD applies to 

certain Boeing Model 747 series 

airplanes. That NPRM was published in 

the Federal Register on May 25, 2006 

(71 FR 30090). That NPRM proposed to 

continue to require inspections to detect 

disbonding, corrosion, and cracking at 

the longitudinal rows of fasteners in the 

bonded skin panels in section 41 of the 

fuselage, and repair, if necessary. That 

NPRM also proposed to add airplanes to 

the applicability of the existing AD, and 

require new inspections of airplanes 

that may have Alodine-coated rivets 

installed. 

Comments 

We provided the public the 

opportunity to participate in the 

development of this AD. We have 

considered the comments that have 

been received on the NPRM. 

Support for the NPRM 

Boeing supports the NPRM. 


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56862 Federal Register / Vol. 71, No. 188 / Thursday, September 28, 2006 / Rules and Regulations 

Request To Clarify Inspection 

Applicability in Paragraph (g)(1) of the 

NPRM 

Northwest Airlines (NWA) requests 

that we use ‘‘and/or’’ in place of ‘‘and’’

in paragraph (g)(1) of the NPRM, as 

follows: ‘‘* * * do initial inspections of 

Area 4 and repetitive inspections, as 

applicable, to detect disbonding, 

corrosion, and/or cracking of the skin; 

* * *.’’ NWA explains that changing 

‘‘and’’ to ‘‘and/or’’ provides clear 

instruction for accomplishing the 

inspection of Area 4 using one of the 

inspection methods defined in Figure 18 

or 20 of Boeing Alert Service Bulletin 

747–53A2409, Revision 5, dated August 

18, 2005, which was referenced in the 

NPRM as the appropriate source of 

service information for accomplishing 

the required actions. NWA states that 

the requested change eliminates all 

possibility of interpreting the NPRM to 

require a specific inspection for 

disbonding, corrosion, and cracking 

using the applicable method for each 

inspection as defined in the service 

bulletin. NWA also states that this 

change would duplicate the inspection 

methods specified in paragraphs (b), (h), 

and (n) of AD 96–23–02, which used the 

words ‘‘and/or’’ in a similar context. 

This change would ensure the NPRM 

provides clear definition that an 

operator would accomplish one 

inspection using the applicable method 

to detect disbonding, corrosion, or 

cracks, rather than accomplishing three 

inspections for three specific and 

separate conditions. 

We agree that the paragraph should be 

clarified to provide clear instruction for 

accomplishing the inspection of Area 4 

using one of the inspection methods 

defined in the service bulletin. We 

disagree with using the words ‘‘and/or.’’

Our recent policy has been to avoid 

using and/or, which can often be subject 

to misinterpretation. Therefore, we have 

changed paragraph (g)(1) of this AD by 

adding ‘‘as applicable’’ at the end of the 

phrase as follows: ‘‘* * * do initial 

inspections of Area 4 and repetitive 

inspections, as applicable, to detect 

disbonding, corrosion, and cracking of 

the skin, as applicable; * * * .’’

Request To Clarify Inspection Methods 

in Paragraph (g)(1) of the NPRM 

NWA also requests that we change the 

inspection methods in paragraph (g)(1) 

of the NPRM from ‘‘Method 1 or 2’’ to 

‘‘Method 2, 3, or 4’’ as follows: ‘‘If 

inspection Method 2, 3, or 4 is used and 

no disbonded doubler is found, no 

further action is required by this AD.’’

NWA explains that changing the 

inspection methods from ‘‘Method 1 or 

2’’ to ‘‘Method 2, 3, or 4’’ would define 

the inspection methods necessary to 

inspect the fuselage skins. Inspection 

Method 1 is an external ultrasonic 

inspection that is not applicable to Area 

4. Inspection Methods 2, 3, and 4 are 

inspections that apply to Area 4 and are 

defined in Figure 20 of the service 

bulletin. 

We partially agree. We agree that 

inspection Method 1 does not belong in 

the paragraph because the Method 1 

inspection is applicable only to areas 1, 

2, and 3. We disagree with including 

Methods 3 and 4 in a statement that 

contains the words, ‘‘no further action is 

required by this AD.’’ Inspection 

Methods 3 and 4 are repetitive 

inspections. If we included these 

inspection methods in this statement, 

then the repetitive inspections would no 

longer be required. Therefore, we have 

changed the specified part of paragraph 

(g)(1) of the final rule as follows: ‘‘If 

inspection Method 2 is used and no 

disbonded doubler is found, no further 

action is required by this AD.’’

Furthermore, we eliminated all other 

references to Method 1 from the 

paragraph. 

Conclusion 

We have carefully reviewed the 

available data, including the comments 

that have been 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 

There are about 623 airplanes of the 

affected design in the worldwide fleet. 

The following table provides the 

estimated costs for U.S. operators to 

comply with this AD. The average labor 

rate is $80 per work hour. 

ESTIMATED COSTS

Action Work hours 

Cost per 

airplane, per 

inspection 

cycle 

U.S.-registered 

airplanes 

Fleet cost, per 

inspection cycle 

Inspections (required by AD 96–23–02, and continued in this AD) ........ 308 $24,640 79 $1,946,560. 

New inspections (for airplanes with Alodine-coated rivets) ..................... 42 3,360 96 Up to $322,560. 

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 regulatory evaluation 

of the estimated costs to comply with 

this AD and placed it in the AD docket. 


jlentini on PROD1PC65 with RULES
Federal Register / Vol. 71, No. 188 / Thursday, September 28, 2006 / Rules and Regulations 56863 

See the ADDRESSES section for a location 

to examine the regulatory evaluation. 

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 Federal Aviation 

Administration (FAA) amends § 39.13 

by removing amendment 39–9807 (61 

FR 57994, November 12, 1996) and by 

adding the following new airworthiness 

directive (AD): 

2006–20–02 Boeing: Amendment 39–14771. 

Docket No. FAA–2006–24865; 

Directorate Identifier 2005–NM–194–AD. 

Effective Date 

(a) This AD becomes effective November 2, 

2006. 

Affected ADs 

(b) This AD supersedes AD 96–23–02. 

Applicability 

(c) This AD applies to Boeing Model 747–

100, 747–100B, 747–100B SUD, 747–200B, 

747–200C, 747–200F, 747–300, 747–400, 

747–400D, 747–400F, 747SR, and 747SP 

series airplanes, certificated in any category; 

as identified in Boeing Alert Service Bulletin 

747–53A2409, Revision 5, dated August 18, 

2005. 

Unsafe Condition 

(d) This AD results from a report of 

cracking discovered in a skin lap joint that 

was previously inspected using the eddy 

current method. We are issuing this AD to 

prevent rapid decompression of the airplane 

due to disbonding and subsequent cracking 

of the skin panels. 

Compliance 

(e) You are responsible for having the 

actions required by this AD performed within 

the compliance times specified, unless the 

actions have already been done. 

Requirements of AD 96–23–02 

Actions for Groups 1 Through 10, and 17 

Through 36, as Specified in Boeing Alert 

Service Bulletin 747–53A2409, Revision 5 

(f) For airplanes identified as Groups 1 

through 10 inclusive, and 17 through 36 

inclusive, in Boeing Alert Service Bulletin 

747–53A2409, Revision 5, dated August 18, 

2005: Do the inspections in paragraph (f)(1) 

of this AD; and do the corrective action in 

paragraph (f)(2) of this AD as applicable. 

Except as provided by paragraph (i) of this 

AD, do all actions in accordance with the 

Accomplishment Instructions of Boeing Alert 

Service Bulletin 747–53A2409, dated 

September 26, 1996; or Revision 5, dated 

August 18, 2005. After the effective date of 

this AD, only Revision 5 of the service 

bulletin may be used. 

(1) At the applicable time in Figures 1, 2, 

18, and 20 of Revision 5 of the service 

bulletin, do initial and repetitive inspections 

of Areas 1 and 4, as applicable, to detect 

disbonding, corrosion, and cracking of the 

skin; except any inspection using Method 1 

or 2 must not be accomplished before the 

latest of the following, as applicable: Before 

the accumulation of 2,000 total flight cycles; 

2,000 flight cycles since modification to the 

stretched upper deck (SUD) configuration; or 

2,000 flight cycles since skin panel 

replacement in accordance with AD 90–26–

10, amendment 39–6836. If inspection 

Method 1 or 2 is used and no disbonded 

doubler is found, no further action is 

required by this AD. 

(2) If any corrosion or cracking is found 

during any inspection required by paragraph 

(f)(1) of this AD: Before further flight, except 

as provided by paragraph (i) of this AD, 

repair and do any applicable related 

investigative actions in accordance with the 

Accomplishment Instructions of Revision 5 

of the service bulletin. 

New Requirements of This AD 

Actions for Groups 11 Through 16 as 

Specified in Boeing Alert Service Bulletin 

747–53A2409, Revision 5 (Airplanes Added 

to the Applicability of This AD) 

(g) For airplanes identified as Groups 11 

through 16 inclusive in Boeing Alert Service 

Bulletin 747–53A2409, Revision 5, dated 

August 18, 2005: Do the inspections in 

paragraph (g)(1) of this AD; and do the 

corrective action in paragraph (g)(2) of this 

AD as applicable. Except as provided by 

paragraph (i) of this AD, do all actions in 

accordance with the Accomplishment 

Instructions of Boeing Alert Service Bulletin 

747–53A2409, Revision 5, dated August 18, 

2005. 

(1) At the applicable time in Figures 18 and 

20 of the service bulletin, do initial 

inspections of Area 4 and repetitive 

inspections, as applicable, to detect 

disbonding, corrosion, and cracking of the 

skin, as applicable; except any inspection 

using Method 2 must not be accomplished 

before the latest of the following, as 

applicable: Before the accumulation of 2,000 

total flight cycles; 2,000 flight cycles since 

modification to the SUD configuration; or 

2,000 flight cycles since skin panel 

replacement in accordance with AD 90–26–

10. If inspection Method 2 is used and no 

disbonded doubler is found, no further action 

is required by this AD. 

(2) If any corrosion, disbonding, or 

cracking is found during any inspection 

required by paragraph (g)(1) of this AD, 

before further flight: Repair and do any 

applicable related investigative actions in 

accordance with the Accomplishment 

Instructions of the service bulletin. 

Actions for Airplanes With Alodine-Coated 

Rivets for Groups 1 Through 10, and 17 

Through 36 as Specified in Boeing Alert 

Service Bulletin 747–53A2409, Revision 5 

(h) For airplanes identified as Groups 1 

through 10 inclusive, and 17 through 36 

inclusive, in Boeing Alert Service Bulletin 

747–53A2409, Revision 5, dated August 18, 

2005: Do the inspections in paragraph (h)(1) 

of this AD; and do the corrective action in 

paragraph (h)(2) of this AD if necessary. 

Except as provided by paragraph (i) of this 

AD, do all actions in accordance with the 

Accomplishment Instructions of Boeing Alert 

Service Bulletin 747–53A2409, Revision 5, 

dated August 18, 2005. 

(1) At the applicable time in Figures 21 and 

22 of the service bulletin: Do initial and 

repetitive inspections of Areas 1 and 4, as 

applicable, to detect cracking of the skin. 

(2) If any cracking is found during any 

inspection required by paragraph (h)(1) of 

this AD, before further flight: Repair in 

accordance with the Accomplishment 

Instructions of the service bulletin. 

Exceptions 

(i) Do all actions in accordance with the 

applicable service bulletin except as 

provided by paragraphs (i)(1), (i)(2), (i)(3), 

(i)(4), and (i)(5) of this AD. 

(1) For the action in paragraph (f)(1) of this 

AD: Where Boeing Alert Service Bulletin 

747–53A2409, dated September 26, 1996; 

and Boeing Alert Service Bulletin 747–

53A2409, Revision 5, dated August 18, 2005; 

specify a compliance time after the issuance 

of any revision of the service bulletin, this 

paragraph requires compliance before the 

specified compliance time after November 

27, 1996 (the effective date of AD 96–23–02). 

(2) For the actions in paragraphs (g)(1) and 

(h)(1) of this AD: Where Boeing Alert Service 

Bulletin 747–53A2409, Revision 5, dated 

August 18, 2005, specifies a compliance time 

after the issuance or receipt of any revision 

of the service bulletin, this paragraph 

requires compliance before the specified 

compliance time after the effective date of 

this AD. 

(3) For any repair or any inspection where 

Boeing Alert Service Bulletin 747–53A2409, 

Revision 5, dated August 18, 2005, specifies 

to contact the manufacturer for further 

instructions: Before further flight, repair or 

inspect using a method approved in 

accordance with the procedures specified in 

paragraph (k) of this AD. 

(4) If corrosion is found during any 

inspection required by this AD, before further 

flight: Repair in accordance with an FAAapproved method. 

(5) Where Boeing Alert Service Bulletin 

747–53A2409, Revision 5, dated August 18, 

2005, specifies that it is not necessary to 

count flight cycles at 2.0 psi or less cabin 

differential pressure, this AD does not allow 

for that adjustment factor. 

Credit for Actions Accomplished Previously 

(j) Actions done before the effective date of 

this AD in accordance with the service 

bulletins specified in Table 1 of this AD are 

acceptable for compliance with the 

corresponding requirements of paragraphs (f) 

and (g) of this AD. 


jlentini on PROD1PC65 with RULES
56864 Federal Register / Vol. 71, No. 188 / Thursday, September 28, 2006 / Rules and Regulations 

TABLE 1.—CREDIT SERVICE BULLETINS

Service bulletin Revision 

level Date 

Boeing Service Bulletin 747–53A2409 .................................................................................................................... 1 May 29, 1997. 

Boeing Service Bulletin 747–53A2409 .................................................................................................................... 2 August 6, 1998. 

Boeing Service Bulletin 747–53A2409 .................................................................................................................... 3 October 22, 1998. 

Boeing Service Bulletin 747–53A2409 .................................................................................................................... 4 February 17, 2000. 

Alternative Methods of Compliance (AMOCs) 

(k)(1) The Manager, Seattle Aircraft 

Certification Office (ACO), FAA, has the 

authority to approve AMOCs for this AD, if 

requested in accordance with the procedures 

found in 14 CFR 39.19. 

(2) Before using any AMOC approved in 

accordance with § 39.19 on any airplane to 

which the AMOC applies, notify the 

appropriate principal inspector in the FAA 

Flight Standards Certificate Holding District 

Office. 

(3) AMOCs approved previously in 

accordance with AD 96–23–02, are approved 

as AMOCs for the corresponding provisions 

of paragraph (f) of this AD, except AMOCs for 

terminating action based upon inspection 

results using a sliding probe low frequency 

eddy current (LFEC), sliding probe high 

frequency eddy current (HFEC), or mid 

frequency surface eddy current (MFEC) 

inspection methods; and provided that any 

alternative method for future inspections did 

not incorporate a sliding probe LFEC, sliding 

probe HFEC, or MFEC inspection methods. 

(4) An AMOC that provides an acceptable 

level of safety may be used for any repair 

required by this AD, if it is approved by an 

Authorized Representative for the Boeing 

Commercial Airplanes Delegation Option 

Authorization Organization who 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. 

Material Incorporated by Reference 

(l) You must use Boeing Alert Service 

Bulletin 747–53A2409, dated September 26, 

1996; or Boeing Alert Service Bulletin 747–

53A2409, Revision 5, dated August 18, 2005, 

as applicable, to perform the actions that are 

required by this AD, unless the AD specifies 

otherwise. 

(1) The Director of the Federal Register 

approved the incorporation by reference of 

Boeing Alert Service Bulletin 747–53A2409, 

Revision 5, dated August 18, 2005, in 

accordance with 5 U.S.C. 552(a) and 1 CFR 

part 51. 

(2) On November 27, 1996 (61 FR 57994, 

November 12, 1996), the Director of the 

Federal Register approved the incorporation 

by reference of Boeing Alert Service Bulletin 

747–53A2409, dated September 26, 1996. 

(3) Contact Boeing Commercial Airplanes, 

P.O. Box 3707, Seattle, Washington 98124–

2207, for a copy of this service information. 

You may review copies at the Docket 

Management Facility, U.S. Department of 

Transportation, 400 Seventh Street, SW., 

Room PL–401, Nassif Building, Washington, 

DC; on the Internet at http://dms.dot.gov; or 

at the National Archives and Records 

Administration (NARA). For information on 

the availability of this material at the NARA, 

call (202) 741–6030, or go to http:// 

www.archives.gov/federal_register/code_of_

federal_regulations/ibr_locations.html. 

Issued in Renton, Washington, on 

September 14, 2006. 

Kalene C. Yanamura, 

Acting Manager, Transport Airplane 

Directorate, Aircraft Certification Service. 

[FR Doc. 06–8227 Filed 9–27–06; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2005–23392; Directorate 

Identifier 2005–NE–47–AD; Amendment 39–

14776; AD 2006–20–07] 

RIN 2120–AA64 

Airworthiness Directives; Rolls-Royce 

Corporation Models 250–C30, 250–C40, 

and 250–C47 Series Turboshaft 

Engines 

AGENCY: Federal Aviation 

Administration (FAA), Department of 

Transportation (DOT). 

ACTION: Final rule. 

SUMMARY: The FAA is adopting a new 

airworthiness directive (AD) for RollsRoyce Corporation (RRC) models 250–

C30, 250–40, and 250–C47 series 

turboshaft engines with a third-stage 

turbine wheel, part number (P/N) 

6898663 or P/N 23065843 installed, or 

a fourth-stage turbine wheel, P/N 

6892764 or P/N 23066744, installed. 

This AD adds an additional life limit for 

third- and fourth-stage turbine wheels. 

This AD results from analysis by RRC of 

failures of third-stage turbine wheels. 

We are issuing this AD to prevent loss 

of power, possible engine shutdown, or 

uncontained engine failure. 

DATES: This AD becomes effective 

November 2, 2006. The Director of the 

Federal Register approved the 

incorporation by reference of certain 

publications listed in the regulations as 

of November 2, 2006. 

ADDRESSES: You can get the service 

information identified in this AD from 

Rolls-Royce Corporation, P.O. Box 420, 

Indianapolis, IN 46206–0420; telephone 

(317) 230–6400; fax (317) 230–4243. 

You may examine the AD docket on 

the Internet at http://dms.dot.gov or in 

Room PL–401 on the plaza level of the 

Nassif Building, 400 Seventh Street, 

SW., Washington, DC. 

FOR FURTHER INFORMATION CONTACT: John 

Tallarovic, Aerospace Engineer, Chicago 

Aircraft Certification Office, FAA, 2300 

East Devon Avenue, Des Plaines, IL 

60018–4696; telephone (847) 294–8180; 

fax (847) 294–7834. 

SUPPLEMENTARY INFORMATION: The FAA 

proposed to amend 14 CFR part 39 with 

a proposed AD. The proposed AD 

applies to RRC models 250–C30, 250–

40, and 250–C47 series turboshaft 

engines. We published the proposed AD 

in the Federal Register on January 25, 

2006 (71 FR 4065). That action proposed 

to add an additional life limit for thirdand fourth-stage turbine wheels. 

Examining the AD Docket 

You may examine the docket that 

contains the AD, any comments 

received, and any final disposition in 

person at the Docket Management 

Facility Docket Office between 9 a.m. 

and 5 p.m., Monday through Friday, 

except Federal holidays. The Docket 

Office (telephone (800) 647–5227) is 

located on the plaza level of the 

Department of Transportation Nassif 

Building at the street address stated in 

ADDRESSES. Comments will be available 

in the AD docket shortly after the DMS 

receives them. 

Comments 

We provided the public the 

opportunity to participate in the 

development of this AD. We have 

considered the comments received. 

Request to Correct Factual Errors 

One commenter, RRC, requests that 

we correct factual errors in the NPRM 

and revise the Discussion paragraph, to 

state that: 

• Only third-stage turbine wheels 

actually failed in the past; and 

• Only the third-stage turbine wheel 

(not the third-and-fourth-stage turbine 


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