Airworthiness Directives; Rolls-Royce Corporation Turboshaft Engines

[Federal Register Volume 82, Number 173 (Friday, September 8, 2017)]
[Rules and Regulations]
[Pages 42443-42445]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-18910]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2011-0961; Product Identifier 2011-NE-22-AD; Amendment 
39-19023; AD 2017-18-14]
RIN 2120-AA64


Airworthiness Directives; Rolls-Royce Corporation Turboshaft 
Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: We are superseding Airworthiness Directive (AD) 2015-02-22 for 
certain Rolls-Royce Corporation (RRC) model 250 turboprop and 
turboshaft engines. AD 2015-02-22 required repetitive visual 
inspections and fluorescent-penetrant inspection (FPIs) on certain 3rd-
stage and 4th-stage turbine wheels for cracks in the turbine wheel 
blades. This AD requires repetitive visual inspections and FPIs of 3rd-
stage turbine wheels while removing from service 4th-stage turbine 
wheels. We are also revising the applicability to remove all RRC 
turboprop engines and add additional turboshaft engines. This AD was 
prompted by our finding that it is necessary to remove the 4th-stage 
wheels at the next inspection. We are issuing this AD to address the 
unsafe condition on these products.

DATES: This AD is effective October 13, 2017.

ADDRESSES: See the FOR FURTHER INFORMATION CONTACT section.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2011-
0961; 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 final rule, 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.

FOR FURTHER INFORMATION CONTACT: John Tallarovic, Aerospace Engineer, 
FAA, Chicago ACO Branch, Compliance and Airworthiness Division, 2300 E. 
Devon Ave., Des Plaines, IL 60018; phone:

[[Page 42444]]

847-294-8180; fax: 847-294-7834; email: [email protected].

SUPPLEMENTARY INFORMATION: 

Discussion

    We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR 
part 39 to supersede AD 2015-02-22, Amendment 39-18090 (80 FR 5452, 
February 2, 2015), (``AD 2015-02-22''). AD 2015-02-22 applied to 
certain RRC 250-B17, -B17B, -B17C, -B17D, -B17E, -B17F, -B17F/1, -B17F/
2, turboprop engines; and 250-C20, -C20B, -C20F, -C20J, -C20R, -C20R/1, 
-C20R/2, -C20R/4, -C20S, and -C20W turboshaft engines. The NPRM 
published in the Federal Register on March 29, 2017 (82 FR 15474). The 
NPRM was prompted by our determination that it is necessary to remove 
the 4th-stage wheels at the next inspection. The NPRM proposed to 
require repetitive visual inspections and FPIs of 3rd-stage turbine 
wheels while removing from service 4th-stage turbine wheels. We are 
also revising the applicability to remove all RRC turboprop engines and 
add additional turboshaft engines. We are issuing this AD to prevent 
failure of the 3rd-stage and 4th-stage turbine wheel blades, damage to 
the engine, and damage to the aircraft.

Comments

    We gave the public the opportunity to participate in developing 
this AD. The following presents the comments received on the NPRM and 
the FAA's response to each comment.

Request To Remove Certain 3rd Stage Turbine Wheel From AD

    RRC requested that we remove references in this AD to the 3rd stage 
turbine wheel, part number (P/N) RR30000236, installed on the RRC 250-
C300/A1 and 250-C300/B1 turboshaft engines. RRC indicated that 3rd 
stage turbine wheels, P/N RR30000236, are not susceptible to cracks. 
RRC noted that there have been no cracks observed on 3rd stage wheels 
installed on RRC 250-C300/A1 or 250-C300B/1 engines.
    We agree. The 3rd stage turbine wheel, P/N RR30000236, installed on 
RRC 250-C300/A1 and 250-C300/B1 engines does not require inspections. 
They are subject to less severe operating conditions and are not 
susceptible to this type of failure. We removed references to the 3rd 
stage turbine wheel, P/N RR30000236, from this AD.

Request To Revise Power Turbine Reference

    RRC requested that we change references in this AD from ``power 
turbine'' to ``turbine.'' RRC noted that this AD should refer to the 
entire turbine module rather than just to the power turbine. RRC also 
commented that the risk analysis for this AD is based on changing the 
parts anytime the turbine is being serviced, not just the power 
turbine. Revising the reference in this AD to ``turbine'' would remove 
the affected 4th stage turbine wheels from the fleet in a shorter time 
period since the actions specified in this AD are to be complied with 
whenever the turbine is at the shop and is dissembled for any reason, 
or at the next turbine wheel replacement, whichever occurs first.
    We agree. We changed the reference in the Compliance section of 
this AD from ``power turbine'' to ``turbine.''
    RRC also commented that changing the references to ``turbine'' 
would allow for removal of the Definition section from this AD.
    We disagree. The term ``engine shop visit'' is used as one of the 
criteria in this AD to determine when an inspection of affected 
applicable turbine wheels is required. Given that ``engine shop visit'' 
may be interpreted in different ways, we provide a definition for this 
term in this AD. We did not change this AD.

Request To Clarify Removal of Blades With Cracks From Service

    RRC requested that we revise the Compliance section of this AD so 
that it does not require removal from service all turbine wheels found 
with cracks. RRC commented that only certain cracks are related to this 
AD and are a safety concern.
    We agree. The intent of this AD is to address cracks at the 
trailing edge of the turbine wheel blades, near the fillet at the rim. 
The maintenance manuals for these engines allow certain cracks in areas 
of the turbine wheels not subject to this AD. Engines may still operate 
safety with turbine wheels that have allowable cracks. We revised 
paragraph (f)(3) of this AD to refer to cracks found at the trailing 
edge, near the fillet at the rim, of the turbine blades.

Revision to Costs of Compliance

    We reduced the estimated cost of inspection of 3rd stage wheels 
from $320,365 to $288,320 since we removed the 3rd stage wheel, P/N 
RR30000236, from the applicability of this AD. As noted in our previous 
comment response, these P/N 3rd stage wheels are not subject to the 
unsafe condition identified in this AD.

Conclusion

    We reviewed the relevant data, considered the comments received, 
and determined that air safety and the public interest require adopting 
this AD with the changes described previously and minor editorial 
changes. We have determined that these minor changes:
    <bullet> Are consistent with the intent that was proposed in the 
NPRM for correcting the unsafe condition; and
    <bullet> Do not add any additional burden upon the public than was 
already proposed in the NPRM.
    We also determined that these changes will not increase the 
economic burden on any operator or increase the scope of this AD.

Costs of Compliance

    We estimate that this AD affects 3,769 engines installed on 
airplanes of U.S. registry.
    We estimate the following costs to comply with this AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
              Action                     Labor cost             Parts cost            product        operators
----------------------------------------------------------------------------------------------------------------
Inspect 3rd-stage wheels, P/N       1 work-hour x $85     $0....................             $85        $288,320
 23065818.                           per hour = $85.
Replace 4th-stage wheel, P/N        0 work-hours x $85    5,653 (pro-rated cost            5,653      21,306,157
 23055944 or RR30000240.             per hour = $0.        of part).
----------------------------------------------------------------------------------------------------------------

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,

[[Page 42445]]

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.
    This AD is issued in accordance with authority delegated by the 
Executive Director, Aircraft Certification Service, as authorized by 
FAA Order 8000.51C. In accordance with that order, issuance of ADs is 
normally a function of the Compliance and Airworthiness Division, but 
during this transition period, the Executive Director has delegated the 
authority to issue ADs applicable to engines, propellers, and 
appliances to the Manager, Engine and Propeller Standards Branch, 
Policy and Innovation Division.

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),
    (3) Will not affect intrastate aviation in Alaska to the extent 
that it justifies making a regulatory distinction, 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 removing Airworthiness Directive (AD) 
2015-02-22, Amendment 39-18090 (80 FR 5452, February 2, 2015), and 
adding the following new AD:

2017-18-14 Rolls-Royce Corporation: Amendment 39-19023; Docket No. 
FAA-2011-0961; Product Identifier 2011-NE-22-AD.

(a) Effective Date

    This AD is effective October 13, 2017.

(b) Affected ADs

    This AD replaces Airworthiness Directive (AD) 2015-02-22, 
Amendment 39-18090 (80 FR 5452, February 2, 2015).

(c) Applicability

    This AD applies to Rolls-Royce Corporation (RRC) 250-C20, -C20B, 
-C20F, -C20J, -C20R, -C20R/1, -C20R/2, -C20R/4, -C20W, -C300/A1, and 
-C300/B1 turboshaft engines with either a 3rd-stage turbine wheel, 
part number (P/N) 23065818, or a 4th-stage turbine wheel, P/N 
23055944 or RR30000240, installed.

(d) Subject

    Joint Aircraft System Component (JASC) Code 7250, Turbine 
Section.

(e) Unsafe Condition

    This AD was prompted by in-service turbine wheel blade failures 
that revealed the need for changes to the inspections of certain 
3rd-stage turbine wheels and removal from service of certain 4th-
stage turbine wheels. We are issuing this AD to prevent failure of 
the 3rd-stage and 4th-stage turbine wheel blades, damage to the 
engine, and damage to the aircraft.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.
    (1) Within 1,775 hours since last visual inspection and 
fluorescent-penetrant inspection (FPI) or before the next flight 
after the effective date of this AD, whichever occurs later:
    (i) Remove 3rd-stage turbine wheels, P/N 23065818, and perform a 
visual inspection and an FPI on the removed turbine wheels for 
cracks at the trailing edge of the turbine blades, near the fillet 
at the rim.
    (ii) Thereafter, re-inspect the affected turbine wheels every 
1,775 hours since last inspection (HSLI).
    (2) Any time the turbine is disassembled, perform a visual 
inspection and an FPI on 3rd-stage turbine wheels, P/N 23065818, for 
cracks at the trailing edge of the turbine blades, near the fillet 
at the rim.
    (3) Do not return to service any turbine wheels found to have 
cracks at the trailing edge, near the fillet at the rim, of the 
turbine blades.
    (4) Within 1,775 HSLI, or at the next engine shop visit, 
whichever occurs later, remove 4th-stage turbine wheels, P/N 
23055944, from service.
    (5) Within 2,025 HSLI, or at the next engine shop visit, 
whichever occurs later, remove 4th-stage turbine wheels, P/N 
RR30000240, from service.

(g) Definition

    For the purpose of this AD, an ``engine shop visit'' is the 
induction of an engine into the shop for maintenance involving the 
separation of pairs of major mating engine flanges, except that the 
separation of engine flanges solely for the purposes of 
transportation without subsequent engine maintenance does not 
constitute an engine shop visit.

(h) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, FAA, Chicago ACO Branch, Compliance and 
Airworthiness Division, 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 Branch, 
send it to the attention of the person identified in paragraph (i) 
of this AD.
    (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.

(i) Related Information

    For more information about this AD, contact John Tallarovic, 
Aerospace Engineer, FAA, Chicago ACO Branch, Compliance and 
Airworthiness Division, 2300 E. Devon Ave., Des Plaines, IL 60018; 
phone: 847-294-8180; fax: 847-294-7834; email: 
[email protected].

(j) Material Incorporated by Reference

    None.

    Issued in Burlington, Massachusetts, on August 31, 2017.
Robert J. Ganley,
Manager, Engine and Propeller Standards Branch, Aircraft Certification 
Service.
[FR Doc. 2017-18910 Filed 9-7-17; 8:45 am]
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