[Federal Register Volume 83, Number 156 (Monday, August 13, 2018)]
[Rules and Regulations]
[Pages 39874-39877]
[FR Doc No: 2018-17112]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2015-4007; Product Identifier 2015-SW-064-AD; Amendment
39-19351; AD 2018-16-11]
RIN 2120-AA64

Airworthiness Directives; Various Model 234 and Model CH-47D
Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: We are adopting a new airworthiness directive (AD) for various
Model 234 and Model CH-47D helicopters. This AD requires inspections of
the pitch housing and revising the pitch housing retirement life. This
AD was prompted by reports of cracking in the pitch housing lugs. The
actions of this AD are intended to detect and prevent an unsafe
condition on these products.

DATES: This AD is effective September 17, 2018.
    The Director of the Federal Register approved the incorporation by
reference of certain documents listed in this AD as of September 17,
2018.

ADDRESSES: For service information identified in this final rule,
contact Boeing Helicopters, The Boeing Company, 1 S. Stewart Avenue,
Ridley Park, PA 19078, telephone<PHONE_NUMBER>, and Columbia
Helicopters, Inc. (Columbia), 14452 Arndt Road NE, Aurora, OR 97002,
telephone<PHONE_NUMBER>, fax<PHONE_NUMBER>, or at http://www.colheli.com. You may review a copy of the referenced service
information at the FAA, Office of the Regional Counsel, Southwest
Region, 10101 Hillwood Pkwy, Room 6N-321, Fort Worth, TX 76177.

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-2015-
4007; or in person at the Docket Operations Office between 9 a.m. and 5
p.m., Monday through Friday, except Federal holidays. The AD docket

contains this AD, any incorporated-by-reference service information,
the Special Airworthiness Information Bulletin (SAIB), the economic
evaluation, any comments received, and other information. The street
address for the Docket Operations Office (phone:<PHONE_NUMBER>) is U.S.
Department of Transportation, Docket Operations Office, M-30, West
Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE,
Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Chris Bonar, Aerospace Engineer,
Airframe Section, Seattle ACO Branch, FAA, 2200 S 216th Street, Des
Moines, WA 98198; telephone<PHONE_NUMBER>; email
[email protected].

SUPPLEMENTARY INFORMATION:

Discussion

    On March 14, 2017, at 82 FR 13567, the Federal Register published
our notice of proposed rulemaking (NPRM), which proposed to amend 14
CFR part 39 by adding an AD that would apply to Model 234 and Model CH-
47D helicopters with a pitch housing part number (P/N) 145R2075-11,
145R2075-12, 145R2075-13, 145R2075-14, 145R2075-15, 145R2075-16,
234R2075-1, or 234R2075-2 installed. The type certificate (TC) holder
for Model 234 helicopters is Columbia (TC previously held by Boeing
Defense & Space Group), and the TC holders for Model CH-47D helicopters
currently include Columbia, Billings Flying Service, Inc., and Tandem
Rotor, LLC. We did not limit the proposed AD to these TC holders
because we expect additional TC holders of helicopters that are subject
to this same unsafe condition.
    The NPRM was prompted by reports of cracking in the pitch housing
lugs, located on the lead side of the lower vertical pin lug. The
reports initially prompted the FAA to issue SAIB SW-11-03, dated
October 22, 2010, which recommends that all owners and operators of
Columbia Model 234 helicopters perform repetitive ultrasonic
inspections of the lugs. At that time, there were no civil Model CH-47D
helicopters in service. On March 20, 2015, we received a report of
lateral vibration on a Model 234 helicopter caused by a crack in an aft
pitch housing upper lug. The crack was determined to be caused by
fatigue and attributed to underestimated load conditions in the
original life limit calculations. This cracking differed from the
cracking described in the SAIB.
    To correct this unsafe condition, we proposed to require repetitive
eddy current and ultrasonic inspections of the pitch housing. Boeing,
the original manufacturer of both model helicopters, developed service
information for the SAIB ultrasonic inspections, which we proposed to
require in the NPRM. Due to the rapid growth rate, an effective eddy
current inspection must detect an inward-growing crack of no more than
0.10 inch. The NPRM proposed to require, for Columbia helicopters, the
eddy current inspection method specified in Columbia's service
information. Because the other TC holders have not developed service
instructions, we proposed to require the eddy current inspection
procedures for all other helicopters be submitted to the Seattle or
Denver Aircraft Certification Offices for approval.
    We also proposed to require removing the pitch housing from service
when it accumulates a total of 8,200 hours time-in-service (TIS).
Forward pitch housings on Model CH-47D helicopters had no life limit
and the aft pitch housing already had a life limit of 8,200 hours TIS.
For Model 234 helicopters, the forward pitch housing had a life limit
of 12,547 hours TIS and the aft pitch housing had a life limit of
19,077 hours TIS. The NPRM proposed to establish or reduce these life
limits to 8,200 hours TIS for both forward and aft pitch housings,
regardless of the model helicopter.
    The actions specified by the NPRM were intended to detect and
prevent a crack in a pitch housing lug. This condition could result in
loss of a rotor blade and consequent loss of helicopter control.
    Since the NPRM was issued, the FAA's Aircraft Certification Service
has changed its organization structure. The new structure replaces
product directorates with functional divisions. We have revised some of
the office titles and nomenclature throughout this final rule to
reflect the new organizational changes. Additional information about
the new structure can be found in the Notice published on July 25, 2017
(82 FR 34564).

Ex Parte Contact

    On October 25, 2017, after the comment period closed, we had a
teleconference with Columbia about Columbia's service information
identified in the NPRM. Columbia's comment during this teleconference
is addressed below. A summary of this discussion can be found in the
rulemaking docket at http://www.regulations.gov in Docket No. FAA-2015-
4007.

Comments

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

Request

    One commenter supported the actions required by this AD.
    Another commenter requested that we provide more information
regarding our determination to include all Model CH-47D and Model 234
helicopters in this AD, including the number of hours on the failed
Japanese military CH-47 pitch housing. This commenter suggested the
failures may be unique to the Model 234 helicopter or may result from
factors, such as high speed operations, a corrosive Japanese operating
environment, or inaccurate fatigue equations.
    We agree to provide additional information regarding our
determination. The Japanese military CH-47 pitch housing failure
referenced in SAIB SW-11-03 failed due to fatigue cracking initiated by
fretting. The event occurred in 2006, and we do not have access to the
number of hours on the failed pitch housing. The reported pitch housing
lug cracks occurred on both the Model 234 and the Model CH-47D. These
models use identical rotor head design and components, including the
same part-numbered pitch housings. Therefore, we determined that the
life limits for the pitch housings on both models should be the same.
    We found no indication that the lug failure resulted from the
Japanese operating environment. Investigation of the cracking did not
show evidence of damage originating at corrosion sites. The Japanese
operating environment is not unique as these aircraft operate worldwide
in a variety of conditions. We also found no indications that the
failures were due to inaccuracies in the Boeing Model 234 cycle count
equations. Our investigation concluded that the original fatigue life
evaluation excluded certain loading conditions and resulted in a life
limit that was too high.
    Tandem Rotor requested the AD not impose a life limit on the
forward pitch housing or, alternatively, impose a life limit consistent
with the life limit of the MH-47E/G forward pitch housing of 24,975
hours TIS. As part of this request, Tandem Rotor asks us to reconsider
the service lives established by Boeing.
    We disagree. We reviewed newer analyses than those considered by
Boeing, including fatigue loading that was not part of the original
design data. These newer analyses show a life limit is required on both
the forward and aft pitch housings. This is consistent with SAIB SW-11-
03, which included the

forward pitch housing despite cracks having only been found in service
on the aft pitch housing. The newer analyses do not support the 24,975-
hour life limit requested by Tandem Rotor. These helicopters are used
in a wide variety of operations. The life limits required by this AD
assume more severe usage than the average operator in order to fully
cover the range of different operators and usages. Individual operators
may request an alternative method of compliance if sufficient data is
submitted to substantiate a different life limit because their usage is
not as damaging to a particular part.
    Tandem Rotor also requested that the repetitive ultrasonic
inspection interval be increased from 200 hours to 250 hours TIS to
align the inspection with an existing recurring 500-hour eddy current
inspection, thus reducing travel costs and simplifying maintenance
planning for the technician.
    We disagree. We have determined that the 200-hour interval for the
inspection represents an appropriate time in which the required actions
can be performed in a timely manner within the affected fleet, while
still maintaining an adequate level of safety. A 250-hour interval did
not yield a sufficient safety margin when considering all usage
spectrums in the current fleet.
    Columbia requested that we change the AD to make the eddy current
inspection requirement the same for all helicopters. In support of its
request, Columbia states that its service bulletin is proprietary and
should not be incorporated by reference (and thus made publicly
available) as an inspection method in the AD.
    We agree. The inspection methods in the Columbia service
information is specific to Columbia helicopters. Because Columbia is
the only operator of its U.S. fleet, we determined there are no other
operators that need this information to perform the eddy current
inspections. We have changed the AD accordingly.

FAA's Determination

    We have reviewed the relevant information, considered the comments
received, and determined that an unsafe condition exists and is likely
to exist or develop on other products of these same type designs and
that air safety and the public interest require adopting the AD with
the change previously described. This change will not increase the
economic burden on any operator or increase the scope of the AD.

Related Service Information Under 1 CFR Part 51

    We reviewed Boeing Service Bulletin 145R2075-62-0001, Revision 1,
dated September 27, 2011, which specifies updated life limits for the
forward and aft pitch housings and revised overhaul and ultrasonic
inspection procedures for various military Model CH-47 and Model 234
helicopters.
    This service information is reasonably available because the
interested parties have access to it through their normal course of
business or by the means identified in the ADDRESSES section.

Other Related Service Information

    We also reviewed Columbia Helicopters, Inc. Alert Service Bulletin
No. 234-62-A0012, Revision 2, dated March 1, 2016, and Alert Service
Bulletin No. 47D-62-A0002, Revision 0, dated March 1, 2016. This
service information specifies performing repetitive eddy current
inspections, visual inspections, and ultrasonic inspections and for
reducing the life limit of the pitch housing assemblies.

Differences Between This AD and the Service Information

    The service information provides different life limits for the
forward and aft pitch housings, while this AD requires a life limit of
8,200 hours TIS for all pitch housings. The service information
requires either an ultrasonic inspection or a dye penetrant inspection
as part of the overhaul procedures. The service information specifies
different compliance times for the inspections than what this AD
requires.

Costs of Compliance

    We estimate that this AD affects 15 helicopters of U.S. Registry
and that labor costs average $85 per work-hour. Based on these
estimates, we expect the following costs:
     An eddy current inspection requires 4 work-hours for a
total cost of $340 per helicopter and $5,100 for the U.S. fleet, per
inspection cycle.
     An ultrasonic inspection requires 4 work-hours for a total
cost of $340 per helicopter and $5,100 for the U.S. fleet, per
inspection cycle.
     Replacing a pitch housing requires 8 work-hours and parts
cost $13,000, for a total cost of $13,680 per helicopter.

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

    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.
    We prepared an economic evaluation of the estimated costs to comply
with this AD and placed it in the AD docket.

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):

2018-16-11 Various Model 234 and Model CH-47D Helicopters: Amendment
39-19351; Docket No. FAA-2015-4007; Product Identifier 2015-SW-064-
AD.

(a) Applicability

    This AD applies to Model 234 and Model CH-47D helicopters,
regardless of type certificate holder, with a pitch housing assembly
(pitch housing) part number (P/N) 145R2075-11, 145R2075-12,
145R2075-13, 145R2075-14, 145R2075-15, 145R2075-16, 234R2075-1, or
234R2075-2 installed, certificated in any category.

(b) Unsafe Condition

    This AD defines the unsafe condition as a crack in a pitch
housing lug. This condition could result in loss of a rotor blade
and consequent loss of helicopter control.

(c) Effective Date

    This AD becomes effective September 17, 2018.

(d) Compliance

    You are responsible for performing each action required by this
AD within the specified compliance time unless it has already been
accomplished prior to that time.

(e) Required Actions

    (1) Before further flight, remove from service any pitch housing
P/N 145R2075-11, 145R2075-12, 145R2075-13, 145R2075-14, 145R2075-15,
145R2075-16, 234R2075-1, and 234R2075-2 that has accumulated 8,200
hours total time-in-service (TIS).
    (2) Before the pitch housing accumulates 200 hours TIS after the
effective date of this AD and thereafter at intervals not to exceed
200 hours TIS, ultrasonic inspect the pitch housing for a crack in
accordance with Attachment 1, paragraphs F and H through K, of
Boeing Service Bulletin 145R2075-62-0001, Revision 1, dated
September 27, 2011. If there is a crack, replace the pitch housing
before further flight.
    (3) Within 400 hours TIS after the effective date of this AD or
before the pitch housing has accumulated 4,000 hours total TIS,
whichever occurs later, and thereafter at intervals not to exceed
500 hours TIS, eddy current inspect the pitch housing for a crack.
If there is a crack, replace the pitch housing before further
flight. The eddy current inspection must be accomplished using a
method approved by the Manager, Seattle ACO Branch, or by the
Manager, Denver ACO Branch. For a repair method to be approved as
required by this AD, the manager's approval letter must specifically
refer to this AD.

 (f) Alternative Methods of Compliance (AMOCs)

    (1) For operators of helicopters with type certificates issued
by the Denver Aircraft Certificate Office or ACO Branch, the manager
of the Denver ACO Branch, FAA, may approve AMOCs for this AD. Send
your proposal to: Greg Johnson, Senior Aerospace Engineer, Denver
ACO Branch, Compliance and Airworthiness Division, FAA, 26805 East
68th Avenue, Denver, CO 80249; phone:<PHONE_NUMBER>; fax: 303-342-
1088; email: [email protected].
    (2) All other AMOC requests should be sent to the Manager,
Seattle ACO Branch, FAA. Send your proposal to: Chris Bonar,
Aerospace Engineer, Airframe Section, Seattle ACO Branch, FAA, 2200
S 216th Street, Des Moines, WA 98198; telephone<PHONE_NUMBER>;
email [email protected].
    (3) For operations conducted under a 14 CFR part 119 operating
certificate or under 14 CFR part 91, subpart K, we suggest that you
notify your principal inspector, or lacking a principal inspector,
the manager of the local flight standards district office or
certificate holding district office before operating any aircraft
complying with this AD through an AMOC.

(g) Additional Information

    Special Airworthiness Information Bulletin SW-11-03, dated
October 22, 2010 (SAIB); Columbia Helicopters, Inc., Alert Service
Bulletin No. 234-62-A0012, Revision 2, dated March 1, 2016; and
Columbia Helicopters, Inc., Alert Service Bulletin No. 47D-62-A0002,
Revision 0, dated March 1, 2016, which are not incorporated by
reference, contain additional information about the subject of this
AD. You may view the SAIB on the internet at http://www.regulations.gov in the AD Docket. For Columbia service
information identified in this final rule, contact Columbia
Helicopters, Inc., 14452 Arndt Road NE, Aurora, OR 97002, telephone
(503) 678-1222, fax<PHONE_NUMBER>, or at http://www.colheli.com.
You may view a copy of the referenced service information at the
FAA, Office of the Regional Counsel, Southwest Region, 10101
Hillwood Pkwy, Room 6N-321, Fort Worth, TX 76177.

 (h) Subject

    Joint Aircraft Service Component (JASC) Code: 6220, Main Rotor
Head.

(i) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the
incorporation by reference of the service information listed in this
paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do
the actions required by this AD, unless the AD specifies otherwise.
    (i) Boeing Service Bulletin 145R2075-62-0001, Revision 1, dated
September 27, 2011.
    (ii) Reserved.
    (3) For Boeing Helicopters service information identified in
this AD, contact Boeing Helicopters, The Boeing Company, 1 S.
Stewart Avenue, Ridley Park, PA 19078, telephone<PHONE_NUMBER>.
    (4) You may view this service information at FAA, Office of the
Regional Counsel, Southwest Region, 10101 Hillwood Pkwy, Room 6N-
321, Fort Worth, TX 76177. For information on the availability of
this material at the FAA, call<PHONE_NUMBER>.
    (5) You may view this 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<PHONE_NUMBER>, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued in Fort Worth, Texas, on July 27, 2018.
Scott A. Horn,
Deputy Director for Regulatory Operations, Compliance & Airworthiness
Division, Aircraft Certification Service.
[FR Doc. 2018-17112 Filed 8-10-18; 8:45 am]
 BILLING CODE 4910-13-P